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Koert, P., Miedema, S.A., (1981), "Report on the field excursion to the USA April 1981". MSc study, 1981, 54 pages, Report, Delft University of Technology.
Copyright: Dr.ir. S.A. Miedema
REPORT ON THE FIELD EXCURSION
TO THE U.S.A.
APRIL 1981
Section The Technology of Soil Movement
Department of Mechanical Engineering
Delft University of Technology
The Netherlands
Koert, P., Miedema, S.A., (1981), "Report on the field excursion to the USA April 1981". MSc study, 1981, 54 pages, Report, Delft University of Technology.
Copyright: Dr.ir. S.A. Miedema
Cover photo A dredge man, working with the "baggerbeugel",
a long rod with a basket attached to it.
This simple method was used when dredging started in the Netherlands
and, despite the great technical developments which have taken place
more recently, it is still in use today.
Courtesy Dredging Museum Sliedrecht~ the Netherlands.
Field excursion: organisation: Winfried Ponsioen, Hugo de Blank
and Jan Brakel
under the guidance of: Prof. ir. J. de Koning
and ing. J. Brouwer
Report: editing and layout: Sape Miedema and Peter Koert
translation: Lorraine van Dam
photography: Wim den Breejen
typing and layout: Marja Koert
Printed by: Repro-graphic service, Department of Mechanical
Engineering, Delft University of Technology,
Ap ri I 1982.
Koert, P., Miedema, S.A., (1981), "Report on the field excursion to the USA April 1981". MSc study, 1981, 54 pages, Report, Delft University of Technology.
Copyright: Dr.ir. S.A. Miedema
Foreword
Students from the section liThe Technology of Soil Movement"
of the Department of Mechanical Engineering of the Delft
University of Technology have at least one opportunity,
to take part in a foreign field excursion during the final
stages of their study. The aim of such field excursions,
which are organised every two years, is to visit companies
and organi sations outside The Netherlands, which specialise
in dredging technology and this is an essential part of their
study programme.
For thi 5 reason a field trip was planned, to visit the
Eastern and South-Eastern part of the U.S.A.
Such a study visit is. possible only with the support of
organisations and companies in The Netherlands and no less
important is the goodwil I of those who are prepared to
receive the students, in this case the Americans, who gave us
such a warm welcome. We should 1ike to express to them the
gratitude of all who participated in the excursion.
'We should also I ike to thank the members of the Student
Society for the excel lent organisational work which they put
in and our expert mentors, Prof. ir. J. de Koning and ing. J. Brouwer
for thei r technical and touristic advice.
The touristic aspects of the visit were naturally much appreciated
and we had the pleasure of making the aquaintance of our spontaneous
and warmhearted American friends, all of which contributed greatly
to the valuable experience gained during the excursion.
Peter Koert
and Sape Miedema.
Koert, P., Miedema, S.A., (1981), "Report on the field excursion to the USA April 1981". MSc study, 1981, 54 pages, Report, Delft University of Technology.
Copyright: Dr.ir. S.A. Miedema
Contents Page
Participants in the field excursion.
Route fo 11 owed.
Schedule of the field excursion.
1
2
3
1 Introduction. 5
16
13
9
9
9
10
22
22
23
24
26
2 Dredging.
2.1 Introduction.
2.2 Operation of equipment on the sites.
2.2.1 Introduction.
2.2.2 The operation of a split hull trail ing suction hopper
dredger in Charleston, South Carolina.
2.2.3 The operation of a cutter suction dredger in Morgan
City, Louisiana and Mobile Bay, Alabama.
2.2.4 The operation of a dustpan dredger in Mobile Bay,
Alabama.
2.2.5 The operation of a grab dredger in Baltimore, Maryland. 18
2.2.6 A dipper dredger of Great Lakes & Dock Company in 20
Morgan City, Louisiana.
2.3 The Shipbuilders.
2.3.1 Introduction.
2.3.2 Avondale Shipyards, New Orleans, Louisiana.
2.3.3 Southern Shipbuilding Corporation, Slidell, Louisiana.
2.3.4 American Marine & Machinery Co. Inc., Nashville,
Tennessee.
2.3.5 Dredge Masters International, Hendersonvil Ie,
Tennessee.
27
2.3.6 Ellicott, Baltimore, Maryland. 28
Koert, P., Miedema, S.A., (1981), "Report on the field excursion to the USA April 1981". MSc study, 1981, 54 pages, Report, Delft University of Technology.
Copyright: Dr.ir. S.A. Miedema
2.4 Dredge Components. 31
2.4.1 Introduction. 312.4.2 Dredge pumps of Georgia Iron Works, Grovetown,Georgia. 32
2.4.3 Ball-joints of Mobile Pulley & M~chine Works, Mobile, 32
Alabama.
2.4.4 Cutter heads of Florida Machine & Foundry, 34
Jacksonville, Florida.
2.4.5 Deforestation equipm~nt of Fleco, Jacksonville, 36Florida.
3 Research and Development. 37
3.1 Introduction. 373.2 The U.S. Army Corps of Engineers Waterway Experiment 37
Station, Vicksburg, Mississippi.
3.3 The Hydraulic laboratory of Georgia Iron Works, Grovetown, 40
Georgia.
4 Excavation by the use of heavy Earth Moving Equipment. 41
4 .1 In trod uc t ion. 41
4.2 Description of the Tennessee-Tombigbee Waterway, 41
Miss iss i pp i .
4 2 1 Ri
4.2.2 Canal Section. 43
4.2.3 Divide Section. 434.3 E~rth Moving equipment used. 45
5 Environmental Aspects. 47
Koert, P., Miedema, S.A., (1981), "Report on the field excursion to the USA April 1981". MSc study, 1981, 54 pages, Report, Delft University of Technology.
Copyright: Dr.ir. S.A. Miedema
The following 16 persons participated on the field excursion.
From left to right: Sape Miedema, Peter Koert, Rob Hoek,
Hugo de Blank, Jan Brakel, Ron Rijkers,
Kees Jan Verkaik, Pieter de Vries, Prof. ir. J. de Koning,
Winfried Ponsioen, Evert van der Hilst, Rikke van Berk,
ing. J. Brouwer, Peter Akerboom, Rob Gijtenbeek and
Wi m den Breej en.
- 1 -
Koert, P., Miedema, S.A., (1981), "Report on the field excursion to the USA April 1981". MSc study, 1981, 54 pages, Report, Delft University of Technology.
Copyright: Dr.ir. S.A. Miedema
......:.:...;:
New York, New Jersey
Baltimore, Maryland
Rockwell City, Maryland
Hendersonville, Tennessee
Washington, District of Columbia
Jacksonville, Florida
Mobile , Alabama
Slidell, Louisiana
Morgan City, Louisiana
New Orleans, Louisiana
1 Atlanta,Georgia
2 Grovetown, Georgia
3 Charleston, South Carol ina
4
5
6
78
9
12
Vicksburg, Mississippi
Columbus, Mississippi
11 Amory, Mississippi
Nashville, Tennessee
13
14
15
16
17
10
The route fol lowed of the field excursion.
- 2 -
Koert, P., Miedema, S.A., (1981), "Report on the field excursion to the USA April 1981". MSc study, 1981, 54 pages, Report, Delft University of Technology.
Copyright: Dr.ir. S.A. Miedema
Schedule of the field excursion to the U.S.A. in April 1981.
April 10
11
12
13
14
15
16
17
18
19
20
Friday
Saturday
Sunday
Monday
Tuesday
Wednesday
Thursday
Friday
Saturday
Sunday
Monday
Arrival in Atlanta, Georgia (1).
Pick up cars.
General orientation in Atlanta.
Drive to Augusta, Georgia.
Visit to Georgia Iron Works, Grovetown,
Georgia (2).
Drive to Charleston, South Carolina (3).
Visit to Great Lakes Dredge & Dock
Company in Charleston.
Drive to Jacksonvil Ie, Florida (4).
Visit to Florida Machine & Foundry,
Jacksonvi lIe.
Drive to Mobile, Alabama (5).
Visit to Mobile Pulley & Machine Works,
Mobile.
Visit to Bean Dredging Corp, Mobi Ie Bay.
Drive to Slidell, Louisiana (6).
Visit to Southern Shipbuilding Corp., Slidell.
New Orleans - free day.
Visit to Great Lakes Dredge & Dock Company,
Morgan City, Louisiana (7).
- 3 -
Koert, P., Miedema, S.A., (1981), "Report on the field excursion to the USA April 1981". MSc study, 1981, 54 pages, Report, Delft University of Technology.
Copyright: Dr.ir. S.A. Miedema
- 4 -
Apri I 21
22
23
24
25
26
27
28
29
30
May
2
Tuesday
Wednesday
Thursday
Friday
Satu rday
Sunday
Monday
Tuesday
Wednesday
Thursday
Friday
Saturday
Visit to Avondale Shipyard, New Orleans,
Lou is i ana (8).
Heading for Vicksburg, Mi ssissippi (9).
Visit to Waterway Experiment Station, Vicksburg.
Drive to Tennessee-Tombigbee waterway.
Visit to Tennessee-Tombigbee Waterway, between
Columbus (10) and Amory (11), Mississippi.
Drive to Nashvil Ie/Hendersonville.
Visit to American Marine & Machinery Co. Inc.,
Nashville, Tennessee (12).
Visit to Dredge Masters International Inc.,
Hendersonville, Tennessee (13).
Drive to Washington, D.C. (14).
Drive to Washington.
Visit to Washington- free day.
Drive to Baltimore, Maryland (15).
Visit to Ellicott Machine Corporation
Internat iona 1, Ba It imore.
Vis i t Ba I t imo re .
Visit Great Lakes Dredge and Dock Comp.,
Rockwell City, Maryland (16).
Drive to New York, New Jersey (17).
New York- free day.
New York - free day.
Depa rt airport.
Koert, P., Miedema, S.A., (1981), "Report on the field excursion to the USA April 1981". MSc study, 1981, 54 pages, Report, Delft University of Technology.
Copyright: Dr.ir. S.A. Miedema
1 Introduction
In order to assess the present situation in the field of
dredging in the U.S ..A., it is necessary to place it in its
historical context. It is also advisable to gain fi rst hand
experience of the philosophy of those who are involved in
dredging, in relation to their mode of work and the appl ication
of technology. Though the development of dredging technique in the
U.. S.A. cannot be considered in detail in this work, it is
necessary to mention a few of the more noteworthy aspects.
It was around 1855 that the centrifugal pump was first used
for soil/water mixtures in the U,.S.A .. , while the first cutterhead
was introduced about five years later~ The development of the
cutter suction dredger was exclusive to the U.S.A. up to the
Second World War, and as a result the U.S.A. has retained her
leading role in the production of cutterheads, replacable
cutterteeth and wear resistant materials, up to the present time.
Improvements in the techniques relating to the process of, dredging
however, such as the use of spudcarriages, underwater pumps and
more extensive instrumentation, have occured in Europe.
After 1880, the principle of the suction hopper dredger, invented
in the Netherlands in 1878, was further developed by the U.S. Army
Corps of Engineers in the U.S.A. and remained an almost completely
American concern up to about 1960 .. An accelerated development
occured after 1960, especially in the Netherlands, and from this
grew the modern split-hopper trailing suction dredger.
Most of the trai 1ing suction hopper dredgers date from the 1940'ies.
The first dustpan dredgers appeared in the U.S.A. around 1900
and were above alr used for maintenance VtIOrk in the great rivers.
The steam-powered vessels of the U.. S. Army Corps of Engineers
almost all date from the 1930' ies.
- 5 -
Koert, P., Miedema, S.A., (1981), "Report on the field excursion to the USA April 1981". MSc study, 1981, 54 pages, Report, Delft University of Technology.
Copyright: Dr.ir. S.A. Miedema
- 6 -
The somewhat dated state of the dredg ing fleet of both the
u.s. Army Corps of Engineers and of private industry
stimulated the "National Dredging Study" ( 1973-1975 ).
The need to bring the major American harbours to a suitable
navigational depth is one of the primary reasons for the
desire to increase hopper capacity.
This is related, among other things, to the anticipated revival
of the coal trade.
The most important conclusion which arises from the "National
Dredging Study" is that both the U.S. Army Corps of Engineers
and private industry need to extend and modernise their fleets
of trailing suction dredgers and this applies equally to their
dustpan dredgers.
There are sufficient cutter suction dredgers, grab dredgers and
backhoe dredgers in the hands of private industry, to satisfy
present requirements, though it might be advisable to modernise
these vessels too.
As a resul t of the "Nat ional Dredg ing Study" the Corps of Eng ineers
wi I I have a number of vessels built, in the following classes:
large hopper sucton dredger (capacity greater than 4590 m3,
6000 c.y.)
4 medium sized hopper suction dredgers (capacity between 765 and
4590 m3, 1000-6000 c.y.)
3 small hopper suction dredgers (capacity less than 765 m3, 1000 c.y.)
The large trailing suction hopper dredger, the "Wheeler" was in
the last stage of building and has since been del ivered.
Since 1974 the private dredging industry has entered into a number
of "joint ventures", especially with Dutch companies.
This may be related to the extensive development of dredging
equipment in The Netherlands, in particular that of the trailing
suction hopper dredgers.
Koert, P., Miedema, S.A., (1981), "Report on the field excursion to the USA April 1981". MSc study, 1981, 54 pages, Report, Delft University of Technology.
Copyright: Dr.ir. S.A. Miedema
In order of their establ ishment the existing Joint Ventures betv-.een
American and Dutch companies are:
North American Trail ing Co., 27-4~974, a joint venture between
Great Lakes Dredge and Dock Company and Amsterdam Ballast Dredging.
- Eagle Dredging, 3-7-1975, a joint venture between C.F.Bean Corp.
and Adr.Volker Dredging Co.
- Stuyvesant Dredging Inc., 9-2-1979, a joi'nt venture between
Zapata Corp. and Bos-Kal is Westminster.
Another form of co-operation is the Gulf Coast Trailing Co.,
a recent Partnership tetween Atlas Trai 1ing Co. (T .L.James) and
Handy U.S. (H.A.M. U.S. Co. and Dredging International), 1981.
There is also a joint venture between an American and a Dutch
shipbuilder: D.T.C., a joint venture betv-.een John J. McMullen Ass.
Inc. and I.H.C. Holland (30-10-1977).
In general the contribution of a foreign company to such a joint
venture is limited to 25% as a result of the "Jones Act l' (1910).
In addition the direct import of dredging equipment built outside
the U.S.A. is not permitted.
This restriction appl ies only to vessels for use in navigable waters,
equipment intended for the extraction of sand and gravel from pits
may be imported.
In the second chapter the differing aspects of dredging wi 11 be
discussed, though it should be noted that the impressions were gathered
during a number of short visits and therefore they are in no way
camp rehens i ve .
The third chapter is devoted to research and development at the
'IGeorgia Iron Works Hydraulic Laboratory" and the "U.S. Army Engineers
Waterways Exper iment Stat ion 'l .
- 7 -
Koert, P., Miedema, S.A., (1981), "Report on the field excursion to the USA April 1981". MSc study, 1981, 54 pages, Report, Delft University of Technology.
Copyright: Dr.ir. S.A. Miedema
- 8 -
The fourth chapter is devoted to major earth, moving operations
and the Tennessee-Tombigbee canal is considered.
Though dredging is also included in this project we devoted
most of our attention to the large scale earth moving aspects
during our visit to it.
Finally a number of environmental aspects are discussed in chapter
five, in particular the influence whtch the environmental activist
groups are able to exert, especially upon the mode of operation.
Koert, P., Miedema, S.A., (1981), "Report on the field excursion to the USA April 1981". MSc study, 1981, 54 pages, Report, Delft University of Technology.
Copyright: Dr.ir. S.A. Miedema
2 Dredging
2 . 1 tnt roduct ion
In order to obtain an impression of the mode of operation and the
dredging techniques used in the U,.S.A. it is necessary to look at
them from as many angles as possible.
Only when a general yjew has been formed it is possible to evaluate
the separate components and place them in the context of the whole.
Naturally visits to a 1 imited number of companies and work sites,
such as we made, cannot give a true reflection of the state of the
art ,.
Thi s chapter deals with various aspects of dredging,.
Firstly various types of work which produce a variety 'of boundary
conditions,which determine the use of various types of dredging
equipment,are dealt with,.
Secondly a number of builders of the types of equipment used are
considered and finally a number of components used by the builders
are discussed ..
2.2 Operation of equipment on the sites
2.2.1 Introduction
Very diverse boundary COl1ditions determ'ine which type of equipmen
is used for a particular job. The type of material to be dredged
is obviously one of the most important of these.
The extent of the work is also a determining factor, not only the
volume of material in terms of cubic metres, but also the length,
width and depth of the work play their part.
- 9 -
Koert, P., Miedema, S.A., (1981), "Report on the field excursion to the USA April 1981". MSc study, 1981, 54 pages, Report, Delft University of Technology.
Copyright: Dr.ir. S.A. Miedema
- 10 -
Other points which must be taken into consideration are:
- possible interference with navigation
- the regulations which govern the protection of the environment
- local government regulations
This is only a limited number of the whole range of possible boundary
conditions.
Visits to different types of work on a number of sites, made it possi ble
for us to become aquainted with a number of situations and to observe
the cho ise of the most su i tabl e equ i pment ava i lab 1e at the time in
question.
The dredgers on the sites visited were diverse in character but had
thei r American origin in common.
A second characteristic was that a further development in the design
of this equipment had taken place in Europe.
The trailing suction hopper dredgers now be'ing built are equipped
with the most recently developed dredge components and instrumentation.
The cutter suction dredgers are in general rather dated though some of the
more recent ones, however, do have underwater pumps and production
meters.
The dustpan dredgers, the grabs and the dipper dredgers are well
tried and trusted in America, they are less we,ll known and thus used
less in Europe.
2.2.2 The operation of a split hull trailing suction hopper dredger
in Charleston, South Carol ina
General: The trai I ing suction hopper dredger originated in the U.S.A.
and after a period during which it inspired little interest,
it came to the forefront once again towards the end of the seventies,
largely as a result of the development of this type of vessel in
Europe during the sixties and seventies.
In recent years both private industry and the U.S. Army Corps of
Engineers have attempted to increase the trailing suction hopper
dredger capacity by building a number of such vessels of various
sizes.
Koert, P., Miedema, S.A., (1981), "Report on the field excursion to the USA April 1981". MSc study, 1981, 54 pages, Report, Delft University of Technology.
Copyright: Dr.ir. S.A. Miedema
These ships are extremely modern in design and are also automated.
A trend towards the use of underwater pumps for the purpose uf
increasing production as well as the use of the principle of the
spl it hopper can be detected.
The use of the split hopper is applied in both the I'Manhattan Island ll
class and the 'IEagle I".
Charleston: A study by the U.S. Army Corps of Engineers has shown
that the depth of the approach channel giving access
to the harbour of Charleston must be increased from the present
10.5 m (35 ft) to 12 m (40 ft).
Shipyard River, where there are many terminals owned by private
industry, is also being deepened from 9 m (30 ft) to 11.4 (38 ft).
The reason for this is the commercial need to accomodate ships of
greater draught.
Since a trai ling suction hopper dredger does not interfere with
navigation and it can handle the silt which is present. it is the most
suitable type of vessel for this job.
The work on the approach channel is being done by the split hull
trailing suction hopper dredger IIDodge Island l' of the North American
Trail ing Company (NATCO).
This ship is of the 'IManhattan Island'l class and was built by the
Southern Shipbuilding Company, Sl idell, Louisiana.
The cost of the project is estimated to be $ 60 m, with a possible
extension up to $ 10 m more as the material which is dredged must
be di scharged in the Atlantic Ocean to conform the environmental
requirements.
The IIDodge Islandl' is equipped with a constant tonnage loading system,
which in fact is not in use for this project as overflowing over the
coaming during the dredging of the type of si It encountered gives
a higher production.
- 11 -
Koert, P., Miedema, S.A., (1981), "Report on the field excursion to the USA April 1981". MSc study, 1981, 54 pages, Report, Delft University of Technology.
Copyright: Dr.ir. S.A. Miedema
- 12 -
The "Dodge Island"J (NATCO).
The vessel has an installation which enables the silt to be conveyed
ashore by pipel ine.
It is unfortunate that so many of the construction elements for this
installation are located in the hopper, because this substantially
diminishes the advantage of the spl it hopper principle and of the
four ancillary hoppers via which the mixture flows evenly into the
hopper. This also affects the flow and the sinking of the material
in the hopper adversely.
In order to achieve the highest possible production the tangent
line method of economic loading is used.
Koert, P., Miedema, S.A., (1981), "Report on the field excursion to the USA April 1981". MSc study, 1981, 54 pages, Report, Delft University of Technology.
Copyright: Dr.ir. S.A. Miedema
The "Dodge Islandll has a completely automated engine room, which
makes it one of the most modern spl it hull suction hopper dredgers.
The rapid purchase of four of these vessels by the NATCO indicates
that these vessels can competerwell in the American Market.
2.2.3 The operation of a cutter suction dredger in Morgan City,
louisiana and Mobile Bay, Alabama.
General: The older American cutter suction dredgers are in general
characterised by a large super structure, mainly as a result
of the amount of accomodation for the crew, limiting the available
deckspace.
The heavy construction of the spud pole gantry and the ladder gantry
is conspicious, spud carriages not yet being widely used.
The pump and drive motors are often placed together in the engine
room and it is apparently not considered necessary to use watertight
bu 1kheads between them '.
There is however good access to the pump and driving engines, which
facilitates maintenance.
Underwater pumps have only been in use since the beginning of the
seventies.
There is a tendency to increase the degree of instrumentation.
Morgan City: In the Mississippi delta a 120 m (3 broad
navigation channel is be ng dredged to a depth of 7.5 m
(25 ft) from Morgan City. The ground is a soft clay mixed with sand.
The project involves dredging a total of approximately 20.106 m3
(26.106
c.y.) of material.
Thi 5 $ 14 m work has been contracted td' the joint venture between
T.l. James and Williams-McWilliams.
The cutter suction dredger IIFritz Jahncke ll, of the latter company
is being used. This ship, built in 1965, has a total installed
capacity of approximately 4854 kW (6600 hp), of which 3383 kW (4600 hp)
supplies the dredge pump and 883 kW (1200 hp) the cutterhead.
- 13 -
Koert, P., Miedema, S.A., (1981), "Report on the field excursion to the USA April 1981". MSc study, 1981, 54 pages, Report, Delft University of Technology.
Copyright: Dr.ir. S.A. Miedema
- 14 -
The crew of the I'Fritz Jahncke l' , totalling 45, works in three shifts,
two weeks on and one off.
We estimated the production at about 2100 m3/hr (2745 c.y./hr), the
spoil being discharged via a floating pipeline of ca.686 mm (27 inch)
over a distance of 1300 m (4265 ft).
The "Fritz Jahncke".. (Williams-McWilliams).
Mobile May: The IIJim Bean ll, flagship of the C.F. Bean Corp., may
serve as an example of a more modern cutter suction dredger.
This ship was put into operation in Mobile Bay, together with the
cutter suct ion dredger 'IDave Blackburn 'i and the dustpan dredger
"Lenel Bean l' •
The special aspects of the work with this dustpan dredger will be
considered in the section devoted to Mobile Bay.
Koert, P., Miedema, S.A., (1981), "Report on the field excursion to the USA April 1981". MSc study, 1981, 54 pages, Report, Delft University of Technology.
Copyright: Dr.ir. S.A. Miedema
The IIJim Bean " , built in 1973, is a very large cutter suction
dredger with a total power capacity of ca. 11768 kW (16000 hp).
The cutterhead power is ca. 1324 kW (1800 hp) and the length of the
ladder, almost 44 m (144 ft), makes dredging to a depth of 38 m (125 ft)
possible. An underwater pump is located on the ladder, while two
2648 kW (3600 hp) pumps are installed in the vessel, so that it is
possible to discharge spoil over a long distance without the use of
booster stations.
The pipeline has a diameter of ca. 686 mm ( 27 inch). The instrumentation
includes a velocity meter and a concentration meter.
Significant data are monitored together with the calculated production.
There is accomodation for 35 men on board.
The ladder of the "Jim Eean".. (C.F. Bean Corp.).
- 15 -
Koert, P., Miedema, S.A., (1981), "Report on the field excursion to the USA April 1981". MSc study, 1981, 54 pages, Report, Delft University of Technology.
Copyright: Dr.ir. S.A. Miedema
- 16 -
2.2.4 The operation of a dustpan dredger in Mobil Bay, Alabama.
General: The dustpan dredger is typically American in origin being
designed for use in the great rivers such as the Mississippi.
During the last few years there has been a revival in interest in
the use of dustpan dredgers for special works in the Netherlands
(Storm Surge Barrier, Eastern Scheldt).
The dustpan dredger is by definition, suitable for the removal of
layers of sand and gravel to produce a smooth level bottom.
Mobile Bay: During the visit to Mobile Bay where, among other things,
a navigation channel was being dredged, the dustpan dredger
"Lenel Bean" could be observed in action. The IILenel Bean ll is the
only dredger of the dustpan type in the possession of a private
company and was built in 1979.
The $ 49 m project in Mobile Bay comprises the removal of 24.106 m3
(31.106 c.y.) of material.
Near the Theodore Industrial Park a turning circle is being made and
also a new 1inking canal of 10.4 km (34000 ft) long, 122 m (400 ft)
wide and 12.2 m (40 ft) , from the turning circle to the Mobile
ship channel,.
Three dredgers are being used for this work, the cutter suction dredgers
IIDave Blackburn" and "Jim Bean ll and the dustpan dredger !ILene 1 Bean!l.
It would appear that no more suitab work was or the
IILenel Bean l'; such dredgers are usually used for work in rivers,
when the material dredged s s coohe~si,.te.
The making of the turning circle is a typical work for a cutter
suction dredger, in view of the scale of the job.
The 'ILenel Bean ll was the upper layer channel,
comprising silt, mud and clay.
Despite the fact that the suction mouth was frequently blocked,
a good rate of production was being achieved.
During our visit this was estimated at ca. 1250 m3/hr (1634 c.y./hr).
Koert, P., Miedema, S.A., (1981), "Report on the field excursion to the USA April 1981". MSc study, 1981, 54 pages, Report, Delft University of Technology.
Copyright: Dr.ir. S.A. Miedema
In order to progress ahead in the work, the IILene'l Bean ll uses two
crossed bow wires and two propulsion drives on the stern, each
about kW (900 hp). The bow winches are equipped with a constant
regulator (0 -5 in, .. 8-16 ft/min), while the
propulsion di rection can be ed he use of 2 adjustable
z-dr ve screws.
The 9.5 m (31 ft) wide suction head has an inlet height of ca. 0.6 m
(2 ft) which enables a height of 0.9-1.5 m (3-5 ft) 'to be attained.
The suction head is divided into four sections, each of which has
its own suction pipe. These pipes join each other at a bigger one,
which has a diameter of ca. 1067 mm (42 inch). The 1067 mm 1 ine is
directly connected to the 2648 kW (3600 hp) dredge pump, which is
installed in the ship.
The discharge 1 ine has a diameter of about 965 mm (38 inch).
The dredger is connected with a floating booster station by means
of a floating line of about 150 m (500 ft) long, which also has a
diameter of about 965 mm (38 inch).
After this booster station the pipeline is submerged' and this section
has a diameter of ca 686 mm (27 inch)
The distance to the spot 1 area is ca. 4500 m (15000 ft).
The jet systems cons sts of ts above the suction opening.
Twenty of the jets are 51ig y downwards whilst the three
central j s are di upwards These jets are connected to a
central jet-pipeline ader. next page).
crew of the IILene 1 Bean ll s ts of 40 men, who work in three
shifts, two weeks on and one week off
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Koert, P., Miedema, S.A., (1981), "Report on the field excursion to the USA April 1981". MSc study, 1981, 54 pages, Report, Delft University of Technology.
Copyright: Dr.ir. S.A. Miedema
- 18 -
The jet system on the "LeneZ Bean".. (C.F. Eean Corp.).
2.2.5 The operation of a grab dredger in Baltimore, Maryland.
General: Grab dredgers are in very general use in the U.S.A. and
can be operated in a wide range of conditions.
They are much used in situations where there is I ittle room available
for work ing, such as in harbours and on quays.
A big advantage is that great depths can be dredged, although the
rate of production does decl ine rapidly as the depth increases.
If such a dredger is used for works requiring smaller depths, its
production is comparable to that of other types of dredgers.
Koert, P., Miedema, S.A., (1981), "Report on the field excursion to the USA April 1981". MSc study, 1981, 54 pages, Report, Delft University of Technology.
Copyright: Dr.ir. S.A. Miedema
Baltimore: In the Chesapeake Bay, near Rockwell City, a grab dredger
of Great Lakes Dredge & Dock Company (the G.L.54) was
being used to deepen and widen the navigation channel.
This involved digging out a cohesive clay to a depth of 9 m (30 ft)
and transporting it to the spoil area.
The dredger consisted of a grab crane, mounted on a pontoon of
20 x 60 m2 (66 x 197 ft 2).
In the operating position this pontoon is supported by three spud
poles, two fixed forward spuds and one spud aft.
The use of spuds reduces the hindrance to navig@tjon to a minimum
as anchorage wires are not necessary.
When it is necessary to move the pontoon the forward spuds are raised
and then the wa I ki ng spud is used to push the pontoon ahead by
means of a hydraul ic ram.
During our visit the length of the stepD was 16 m (52.5 ft). in a time
of ca. 2m in.
During the movement the direction is more or less controlled by
placing the grab bucket on the ground. The capacity of the grab
is ca. 17 m3 (22 c.y.), the maximum liftspeed is ca. 120 m/min
094 ft/min).
The total installed power is 2942 kW (4000 hp).
We estimated the production during our visit to be ca. 1000-1200 m3/hr
(1300-1600 c.y./hr).
The spoil is transported in large split barges of 2500 m3 (3270 c.y.),
which are equipped with an extra hinge at the middle of the hopper,
necessary to meet the stiffness requirements of the construction
of the vesse I .
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Koert, P., Miedema, S.A., (1981), "Report on the field excursion to the USA April 1981". MSc study, 1981, 54 pages, Report, Delft University of Technology.
Copyright: Dr.ir. S.A. Miedema
- 20 -
The "G.L.54" ~oading a hopper barge~ (Great Lakes Dredge & Dock Compo J.
2.2.6 A dipper dredger of Great Lakes Dredge & Dock Company
in Morgan City, Louisiana.
A very large dipper dredger of Great Lakes Dredge & Dock Company
was in Morgan City, Louisiana,for repair and maintenance after a
period spent dredging rock in Dubai.
The capacity of the bucket was max. 12 m3 (15,7 c.y.) and the maximum
dredg ing depth was ca. 15 m (50 ft).
The steel construction of the boom and some other parts of this old
dipper dredger consisted of rivetted sections.
Koert, P., Miedema, S.A., (1981), "Report on the field excursion to the USA April 1981". MSc study, 1981, 54 pages, Report, Delft University of Technology.
Copyright: Dr.ir. S.A. Miedema
This boom must be of a very heavy construction owing to the very
great breakout forces on the bucket.
In general dippers, I ike backhoe dredgers, are used for very heavy
work, especially in boulder clay and fragmented rock.
A dipperdredge of Great Lakes Dredge & Dock Company.
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Koert, P., Miedema, S.A., (1981), "Report on the field excursion to the USA April 1981". MSc study, 1981, 54 pages, Report, Delft University of Technology.
Copyright: Dr.ir. S.A. Miedema
- 22 -
2.3 The shipbuilders
2.3.1 Introduction
The basic philosophy behind the design of American dredgers differs
on at least one point from the European one.
Most of the dredgers are designed around standard power units
(for pump drives, cutter drives etc.), while in Europe these drives
are more or less adapted to the requirements of the customer, especially
for the larger dredgers.
This means that in America the drives are delivered by the suppliers
out of stock.
In Europe, however, the drives are often designed or adapted for a
particular ship so that, in view of the many possible modifications
which may be called for, it is more expensive to keep them in stock.
American dredgers are also usually built for the American market
with the result tha.t, in view of the general shallowness of American
waterw'ays, it is mainly small and medium .sized vessels which are built.
Of the five American shipyards visited Dredge Masters International
and American Marine & Machinery Co. Inc. concentrated strongly on
the dredging industr~ their principal roducts being demountable
cutter suction dredgers.
Ellicott Machine Cor 0 rnati wi mining
equipment and a s ast.andard·series ()fdE~m()urttalble
cutter suction dre rs and suction dredgers ich are equipped
with the Ellicott dredg el.
In addition Ell icott also produces custom built dustpan dredgers,
grab cranes on pontoons, backhoe dredgers and trail ing suction
hopper dredgers.
Koert, P., Miedema, S.A., (1981), "Report on the field excursion to the USA April 1981". MSc study, 1981, 54 pages, Report, Delft University of Technology.
Copyright: Dr.ir. S.A. Miedema
Southern Shipbuilding Corporation is a typical example of
American private enterprise.
Thi s company has emerged as a pioneer in the building of a new
gene rat ion of Amer i can trai 1ing suct ion hoppe r dredge rs, the
IIManhat tan Is land ll class. These vessels are of functional
construction, with modern equipment.
Finally Avondale Shipyards has one of the largest yards in the
U.S.A., with the characteristics of a major company, it is able
to del iver vessels of the highest technical qual ity (the IIWheeler ll).
2.3.2 Avondale Shipyards, New Orleans, Louisiana.
Avondale Shipyards is one of the largest shipyards in the U.S.A.
Since 1938 more than 2300 vessels have been built by this company.
Avondale builds many types of ships and is also very active in the
offshore field, building drill ing rigs, production platforms and
tanker jetties for the open sea.
The yard is part of the Ogden Corporation. It is a non-union concern,
there are no trade unions in the yard.
Other points worthy of note are that the yard has its own foundry
and that much of the building is done in sections, the maximum weight
per section being about 2500 tons.
The iiWheelerii for example was built in 88 sections. In this sectionai
building, pipelines, pumps etc., are installed before the sections
are assembled.
A number of trail ing suction hopper dredgers have been built by
Avondale Shipyards. These include the "Eagle I", the ""'-'heeler" and
the "Stuyvesant".
The "Eagle III has already been delivered by the time of our visit.
It was built for the Eagle Dredging Company and, with a hopper capacity
of 4820 m3 (6304 c.y.), it is one of the worlds largest seegoing
split hull trailing suction hopper dredgers.
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Koert, P., Miedema, S.A., (1981), "Report on the field excursion to the USA April 1981". MSc study, 1981, 54 pages, Report, Delft University of Technology.
Copyright: Dr.ir. S.A. Miedema
- 24 -
The IIWheeler has been commissioned by the U.S. Army Corps of
Eng ineers.
An unusual technical feature is the third suction arm, which is
located in acentre4Nell in the hopper and is intended for
agitation dredging. It is one ~f the worlds largest trai 1ing suction
hopper dredgers with a hopper capacity of 6423 m3 (8400 c.y.).
The IIStuyvesant ll was built for the Stuyvesant Dredging Company and
is kept in commission by Wi 11 iams-McWi 11 iams.
It is also one of the worlds largest trail ing suction hopper dredgers,
with a hopper capacity of 6735 m3 (8809 c.y.).
Both the IIWheeler l1 and the IIEagle III were designed by D,.T.C. and
in addition D.T.C. has supplied the principle dredge components,
hull hinges and service installations for the IIEagle III.
2.3.3 Southern Shipbuilding Corporation Slidell, louisiana.
This yard has been in existence since 1957, being preceded by the
Conulet Shipyard established in 1918.3 2The extent of the yard is 240.10 m (60 acres) and employs about
350 men.
Southern Shipbuilding Corporation specialises in repair, but is also
moving into other markets.
Flat barges, push boats and tugsand split hull trailing suction
hopper dredgers are built.
Since 1975 Southern Shipbuilding Corporation, a pioneer in the
development of large split hopper systems, has delivered three split
hull trailing suction hopper dredgers of the IIManhattan Island ll class,
while the fourth, the "Padre Island ll 'has under construction, at the
time of our vi sit.
These vesse 1s were a 11 comm i ss ioned by NATCO.
Koert, P., Miedema, S.A., (1981), "Report on the field excursion to the USA April 1981". MSc study, 1981, 54 pages, Report, Delft University of Technology.
Copyright: Dr.ir. S.A. Miedema
The succes of these vessels is illustrated by the fact that NATCO
can submit a lower tender for maintenance work in the approach
channel to the port of Savannah by the "Manhattan Island l' than the
U.S. Army Corps of Engineers can give with the much larger
"Essayons".
An unusual feature of the method of building these vessels is that
parts of them are bui It upside-dovm. This 'greatly facil itates the
welding process and is a building method based on the experience gained
in the construction of tugs in this way.
This is possible because the ships are bui It in sections.
A 1imitation is the hoisting capacity of the yard which has one
movable crane of 50 tons and one floating crane of 350 tons capacity.
The hopper of the "Padre Island", (Southern Shipbuilding Corporation).
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Koert, P., Miedema, S.A., (1981), "Report on the field excursion to the USA April 1981". MSc study, 1981, 54 pages, Report, Delft University of Technology.
Copyright: Dr.ir. S.A. Miedema
- 26 -
The "Padre Island ll was being built in six sections, two centre
sections which form the hopper, two bow sections and two stern sections.
The deckhouse weighs 200 tons and was also being buiJt by Southern
Shipbuilding Corporation.
The split system consists of two hinges and four hydraulic cylinders
with a range of 4.8 m (16 ft).
This gives a maximum opening angle of 2 times 16 degrees which can
be reached in 20 seconds.
The weight is distributed in such a way that the loaded hopper will
open itself, while the unladen hopper will close itself.
Hbrizontal bending moments cause the ship to bend open and these
partly deform the closing beams.
The sealing is achieved by a heavy rubber profile.
The hinges are of a very heavy construction to take up the forces
which might develop in the longitudinal axis as a result of colI ision
or going aground.
The ships of the "Manhattan Island" class have a completely automated
engine room, which places them amongst the most modern types.
The "Padre Island", the building of which took about one year,was completed in September 1981.
2.3.4 American Marine & Machinery Co. Inc., Nashville, Tennessee.
A.M.M.Co. produces demountable cutter suction dredgers which can
be delivered in various sizes.
In addition to the cutter suction dr~4gers, A.M.M.Co. also builds
work boats for the dredging industry.
These tenders are propelled by hydrojets.
The company has been engaged in the bui lding of dredgers for 21 years.
At present there is a staff of 80 men, 40 of whom work in the
production while two or three are concerned with the engineering.
The turnover is $ 6-7 m per annum. About 20 units are produced every
year, more than 70% of these being exported.
Koert, P., Miedema, S.A., (1981), "Report on the field excursion to the USA April 1981". MSc study, 1981, 54 pages, Report, Delft University of Technology.
Copyright: Dr.ir. S.A. Miedema
To ensure that the company can remain in production it is necessary
that at least one large vessel should be delivered each year.
The price of the smallest type of dredger is.$> 210000 and the
1a rg es t $ 5 m.
The smallest cutter suction dredger has 85 kW(115 hp)and a
discharge line with a diameter of 150 mm (6 inch), giving a
production of 78 m3/hr (102 c.y./hr).
The largest cutter suction dredger has 4192 kW (5700 hpJ and a
discharge line with a diameter of 680 mm (27 inch) and delivers
a maximum product ion of 2340 m3/hr (3060 c.y./hr).
It was not clear for what types of material and depth these
production figures were val id.
2.3.5 Dredge Maste rs 1nternat j ona 1, Hende rsonv i lIe, Tennes see.
D.M. I. was established by Don Killom and Don B. King in 1973.
The company is a daughter of Valley Industries Inc., St. Louis,
Mis sou r i .
D.M.I. grew very rapidly and is now an importah~ producer of
cutter suction dredgers and components for the dredging industry.
The cutter suction dredgers are in use in 25 countries throughout
the world.
The work force in Hendersonvil Ie now totals 150 men, working in
two sh ifts, six days per week.
The works has an area of 160.103 m2 (40 acres)., very advantageously
positioned in relation to road, rail and water transport.
The turnover of D.M. I. was $ 7.75 m in 1980 and-is expected to reach
$ 17-18m i n 1981 .
To achieve this, the production staff has bee~more than doubled
and the production capacity increased by the extension of the
machine shops and crane facilities.
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Koert, P., Miedema, S.A., (1981), "Report on the field excursion to the USA April 1981". MSc study, 1981, 54 pages, Report, Delft University of Technology.
Copyright: Dr.ir. S.A. Miedema
- 28 -
It has been real ised that it is very important for a manufacturer
of dredging equipment to be able to deliver spare parts quickly,
so a good stock is held.
In 1980 D.M. I. took over the Dixie Dredge Corporation.
Dixie Dredge produces cutter suction dredgers of standard design
and was one of the pioneers in this field.
It is remarkable that a growing company such as D.M'.I. does not
have a research department though it does co-operate in research
by Texas A. & M. University and other organisations.
D.M. I. has five series of cutter section dredgers on the market,
the "Mudmaster ll being unusual in that it has a ladder on which all
main machinery is mounted.
The ladder therefore runs past its bearings through to the rear.
For this reason the dredge does not need a centre hull.
The power unit is mounted on the rear section of the ladder, while
the underwater pump and the cutter installation are forward.
The raising and lowering of the ladder is accomplished by the use
of hydraulic cylinders. All the cutter suction dredgers built by
D.M.I. are equipped with Hydromaster pumps.
The Hydromaster pumps are also used in the mining and coal
processing industry to pump fly-ash and for various proces~es in the
paper industry.
The pumps were developed by D.M.I ~ in co-operation with Georgia Iron
Works and Mobile Pulley & Machine Works.
The pumps are tested at the hydraulic laboratory of Georgia Iron Works.
2.3.6 Ellicott, Ba.ltimore, Maryland.
The company was founded by Charles E. Ellicott in 1885 and the first
complete dredger, the IIS an Pedro", was built in 1904 and continued
in service for 50 years. Ellicott dredge~s were used during the
excavation of the Panama Canal and on maintenance work in the Suez
Canal as well as many other projects.
Koert, P., Miedema, S.A., (1981), "Report on the field excursion to the USA April 1981". MSc study, 1981, 54 pages, Report, Delft University of Technology.
Copyright: Dr.ir. S.A. Miedema
Up to date ca. 1000 dredgers have been delivered by the company,
600 of these being spread throughout the world.
About 225 men are employed by Ell icott in Baltimore, ca. 100 of them
on production and the rest in office work.
It is noteworthy that the control of stock, production and staff
and general administration has been fully computerised, while the
production machinery is somewhat dated.
In addition to a great number of cutter suction dredgers, Ell icott
also produces other types of dredgers such as dustpan dredgers, grab
cranes on pontoons, backhoe dredgers, trai ling suction hopper
dredgers and the dredge wheel.
Since Ell icott has no slipwa~ it is necessary to hire one for the
assembly of the vessels.
The dredge wheel has proved to be a great success for Ellicott,
especially owing to the alluvial mining industry in the U.S.A.,
for which it has particular advantages.
The use of the dredge wheel makes possible the achievement of the
same production in both cutting directions and the cutting power
is 2-3 times greater than that of a cutterhead with the same power
consumpt ion.
There is 1 ittle spillage and the cutting angle of the buckets is
not influenced by the angle of the ladder.
If a bucket wheel is to be mounted onto a standard suct ion
dredger it is necessary to strengthen the spudpole construction
and to use a spudpole carriage as the greater cutting force must
be absorbed by the spuds.
To secure good production it is essential to have a very accurately
designed spud system.
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Koert, P., Miedema, S.A., (1981), "Report on the field excursion to the USA April 1981". MSc study, 1981, 54 pages, Report, Delft University of Technology.
Copyright: Dr.ir. S.A. Miedema
- 30 -
The present market, 20% dredging and 80% mining, does not have
much interest in the increasing of production ~ the application
of new technical developments.
Little research is done by Ellicott, their production development
being largely the result of feedback from the industry.
A result of this is a conservative product of high quality.
Ellicott stands a good change of international success with the
series of demountable cutter suction dredgers and the new dredge
wheel.
An Ellicott cutter suction dredger.
Koert, P., Miedema, S.A., (1981), "Report on the field excursion to the USA April 1981". MSc study, 1981, 54 pages, Report, Delft University of Technology.
Copyright: Dr.ir. S.A. Miedema
2.4 Dredge Components
2.4.1 Introduction
An important characteristic of many of the components such
as pumps, trail ing suction heads, cutter heads and pipelines,
used in the dredging industry, is that they" are subjected
to very great abrasion when cutting or transporting soil mixtures.
To combat this heavy wear it is necessary to use very wear
resistent material in their fabrication. This leads to the production
of very hard components which are difficult to machine.
For this reason an attempt is made to produce castings to such
a degree of accuracy that very I ittle subsequent working is
requ ired.
Often hardening techniques are used, weld-on methods are developed
and there is a close control on the composition of the materials
used.
The Americans are in the forefront in the field of wear-resistant
materials as illustrated by the example of their replaceable
cutter teeth for cutter-heads.
A visit was made to three companies of about the same size,
(ca. 300-350 personnel), each of which specialised in a specific
product. Georgia Iron Works concentrates on dredge pumps, Mobile
Pulley in the same field, but specialising in bal I-joints and
Florida Machine & Foundry on cutter heads and replaceable teeth.
A possible boundary condition which may face a contractor during
a specific work may be that the area in question is heavily
forested so that before the dredging activities can commence
it is necessary to remove the trees. For this specialised work
earthmoving machinery fitted with special ancillary equipment is used.
An important manufacturer of this equipment is Fleco, a subdivision
of F.M.F.
- 31 -
Koert, P., Miedema, S.A., (1981), "Report on the field excursion to the USA April 1981". MSc study, 1981, 54 pages, Report, Delft University of Technology.
Copyright: Dr.ir. S.A. Miedema
. 2 Dredge pumps of Georgia Iron Works, Grovetown, Georgia .
- 32 -
Georgia Iron Works in Grovetown produces cast iron components
for the dredging industry, but even more for the mining industry
In addition to having a very modern foundry the company has a
spacious laboratory for research into pumps. This distinguishes the
G.I.W.from other pump manufacturers in America and Europe.
The largest castings weigh ca. 15 tons, which is comparable to
those produced in Europe.
As stated, the most important product of G.I.W. is the pump,
which is suitable for the transport of mixtures.
The necessary wear-resistance of the cast iron is achieved by
the special, closely control led composition of the charges and
the retention of great hardness. The hardening process involves
submersion in 1iquid nitrogen, after anneal ing by means of which
the hardness can be increased up to ca. 450-650 HB.
The casting can then sti 11 be machined by grinding. Hardness,
however is not the only requirement for a good product. It is
the optimum relationship between toughness and hardness which
produces a casting which will withstand the conditions encountered
i n p rac t i ce .
An attempt is being made to produce castings with ball shaped
carbide crystals in a martensitic structure. The carbides increase
the hardness, whi Ie the rounded form reduces the brittleness
so that the material is tougher.
Though Georgia Iron Works concentrates on standard pumps, special
models can be designed in co-operation with the customer.
2.4.3 Ball-joints of Mobile Pul ley & Machine Works, Mobile, Alabama.
Mobile Pulley & Machine Works has the capacity to produce very
heavy castings of up to ca. 23 tons. Though this permits the
production of very large dredge pumps, the most important product
of M.P.M. is the ball-joint and this commands a major part of the
worl d ma rket.
Koert, P., Miedema, S.A., (1981), "Report on the field excursion to the USA April 1981". MSc study, 1981, 54 pages, Report, Delft University of Technology.
Copyright: Dr.ir. S.A. Miedema
For the good functioning of a ball-joint, in to great
strength and wear-resistance, the most import is very
low friction between the ball and the socket he moveable joint.
For this reason the ball surfaces are worked in a special way.
The ball is first turned on a specially adapte.d lathe after which,
by mean 5 of a ro 11i ng prace 55 pa ra 11 e 1 to the gr00ves produced
during the machining, the hardness is incre'aseo by strengthening
the surface of the material. This alsb produces a smo&th surface.
The rewelding of worn pumps could also be observed at the M.P. I.
works. For a pump casing of medium size this process took about
one week. The process was effected by the use of a number of
rotating welding heads by means of which continuous welding
could be achieved.
In split pump casings the halves were bolted tog~ther and
provided with a wear layer of equal thickness throughout.
After the removal of the bolts the halves were separated
again by allowing the pump to fall from a suitible height.
Additional products of the M.P.H. are the winches used for the
ladder and spudpoles of suction dredgers.
- 33 -
Koert, P., Miedema, S.A., (1981), "Report on the field excursion to the USA April 1981". MSc study, 1981, 54 pages, Report, Delft University of Technology.
Copyright: Dr.ir. S.A. Miedema
- 34 -
2.4.4 Cutter heads of Florida Machine & Foundry, Jacksonville, Florida.
Florida Machine & Foundry is above all specialised in the production
of cutter heads and replaceable teeth for cutter suction dredgers.
Together with ESCO, F .M.F. is the biggest supplier in the world
in this field.
The largest cutter heads of F.M.F. weigh ca. 32 tons and comprise
a variable numLer of blades, a ring and a hub. The heaviest castings
weigh ca. 4.5 tons.
The various components are connected to each other by the application
of the IIThermit l1 welding process. During this process a special
material is introduced into the enclosed space between the parts,
after which an exothermal reaction leads to the melting of this
material. The advantage of this process is that the properties
of the weld are comparable to those of the casting.
The connection between the blades and the hub is one of the most
heavily loaded parts of the cutter head.
In the design of the cutter heads used for cutting rock, in which
extremely heavy loads are encountered, a safety factor of between
a minimum of 5.7 and a maximum of 9.8 is applied by the F.M.F.
These figures do give some indication of the nature of pulsating
load, but as yet there is insufficient knowledge of the cutting
process to permit a more refined design.
The calculations of strength are based on conventional methods,
by which great simplifications have to be made.
The finite-element method is considered too expensive.
Koert, P., Miedema, S.A., (1981), "Report on the field excursion to the USA April 1981". MSc study, 1981, 54 pages, Report, Delft University of Technology.
Copyright: Dr.ir. S.A. Miedema
With regard to the hardness and weldability of the various components
F.M.F. gives the fol lowing:
- blades: 140-180 HB, welding quality good
- adapter: ca. 300 HB, reasonable to good welding quality
- teeth: 440-550 HB, almost un-weldable.
F.M.F. constructs many Ilcustom built ll cutter heads. The form of
the standard cutter-heads, the so called 'Isl ope arc" should lead
to a more even wear pattern.
A blade of a cutter-head in the mould.. (F.M. F.).
- 35 -
Koert, P., Miedema, S.A., (1981), "Report on the field excursion to the USA April 1981". MSc study, 1981, 54 pages, Report, Delft University of Technology.
Copyright: Dr.ir. S.A. Miedema
- 36 -
2.4.5 Deforestation equipment of Fleco. Jacksonville. Florida.
Fleco is a subdivision of Florida Machine & Foundry. The firm
has specialised in the production of equipment for the machinery
used in deforestation and supplies much of this equlpment to
Caterpillar. The most important products include: a variety of
rakes. v-tree cutters, tree pushers and root ploughs.
An obvious piece of equipment is the millyard fork, which in
addition to being used for the removal of trees, can be used to
handle pipes in a spoil discharge area.
Trees and parts of trees such as roots. can be a great hindrance
during some dredging operations lncluding both dredging in cut
and dredging infil!. An example of this is the work in mangrove swamps.
A millyard fork~ (Fleco).
Koert, P., Miedema, S.A., (1981), "Report on the field excursion to the USA April 1981". MSc study, 1981, 54 pages, Report, Delft University of Technology.
Copyright: Dr.ir. S.A. Miedema
3. Research and Development
3.1 Introduction
In the U.S.A. large scale research in the field of dredging is
carried out by the U.S. Army Corps of Engineers at the U.S. Army
Engineer Waterways Experimental Station, Vicksburg and the Coastal
Engineering kesearch Centre at Fort Belvoi r.
These two research centres carry out work simi lar in nature to
that done by the Delft Hydraul ics Laboratory, the major difference
being that the U.S. Army Corps of Engineers has a military structure,
while the Delft Hydraul ics Laboratory is a civil ian organisation.
In the private sector the Georgia Iron works hydraulic Laboratory,
where experimental work on hydraul ic transport and on the testing
of dredge pumps is possible, plays a prominent part in research.
3.2 The U.S. Army Engineer Waterways Experiment Station, Vicksburg,
Mis sis s ipp i .
The research centre at Vicksburg was established after the
Mississippi flood of 1929, its original purpose being to study
and, if possible, improve the course flow regime of the Mississippi
rive r.
After 1935 a number of facilities, such as the geotechnical and
env i ronmenta 1 1abo rato r i es we re added.
Although the organisation is military, both civi lian and army
engineers work in the "Department Military Projects ll•
This department carries out research for government projects,
but not for private industry.
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Koert, P., Miedema, S.A., (1981), "Report on the field excursion to the USA April 1981". MSc study, 1981, 54 pages, Report, Delft University of Technology.
Copyright: Dr.ir. S.A. Miedema
- 38 -
The most important function of the "Experiment Station" is research
into means of maintenance and possible improvement of the water
ways in the U.S.A.
During wartime research is di rected towards mi I itary objectives.
The budget for civil ian projects is $ 50 m, as against $ 25 m
for mi I itary research. The aim of the environmental laboratory
is_to investigate the effects of mans activities upon the environment,
for example the effects of the discharge of dredge spoil upon
the ecology.
The mi litary research is directed towards the influence of the
terrain upon forms of transport and on camouflage.
An attempt is made to maintain a balance between 'Itrouble shooting 'l
and fundamental research.
The budget of the environmental laboratory is $ 2 m per annum.
One of the projects of the Dredging Operations sections is a study
of the effects on the environment of the discharge of dredge spoil,
as the disposal of the very large volume of spoil produced each
year is a major problem.
Methods are being sought whereby the spoil can be deposited as
efficiently as possible. In this connection the effects on sedimentation
of the chemicals which are added to the spoi I are being studied.
The problem which arises is the disposal of the transport water
which has been polluted by these chemicals.
A model of the navigational channel from Cape Fear to Wilmington N.C.
(25 miles), where there is a marine base, has been bui It.
3 mill ion cubic yards must be dredged annually and this model
will be used to study the influence of the tides upon silt transport.
In this model velocity, sal inity and si It transport can te measured.
Koert, P., Miedema, S.A., (1981), "Report on the field excursion to the USA April 1981". MSc study, 1981, 54 pages, Report, Delft University of Technology.
Copyright: Dr.ir. S.A. Miedema
A modeZ of the navigation channeZ from Cape Fear to WiZmington N.C.
A model of the Tennessee-Tombigbee Waterway has enabled the location
of the various locks and dams to be determined.
- 39 -
Koert, P., Miedema, S.A., (1981), "Report on the field excursion to the USA April 1981". MSc study, 1981, 54 pages, Report, Delft University of Technology.
Copyright: Dr.ir. S.A. Miedema
- 40 -
3.3 The Hydraulic Laboratory of Georgia Iron Works, Grovetown, Georgia.
The Hydraulic Laboratory of the Georgia Iron Works was founded
five years ago for the purpose of measurement and research into
pumps and pipelines. The research is often done in co-operation
with other companies, for example the testing of doppler velocity
meters for Leeds & Notthrop Co.
In co-operation with Augusta College and well known research
scientists such as Prof. K.C. Wilson, annual courses on hydraulic
transport are organised.
These are intended for the designers of pipelines for the transport
of spo i 1.
The present faci 1ities include pipel ines of 76 mm (3 inch), 102 mm
(4 inch), 152 mm (6 inch), 203 mm (8 inch) and 457 mm (18 inch)
ttl i ameter for spoi 1 transport.
A 25 I'll (83 ft) vertical se~tion, for the measurement of the
resistance during the vert~al transport of manganese nodules
is included in the 203 mm (8 inch) pipeline.
All the pipeline systems have a radioactive concentration meter,
an electro-magnetic velocity meter and a doppler velocity meter.
Testing a pump with water takes 20 minutes while a test with
a sand/water mixture lasts 10 hours.
The aim is to achieve a stationary flow in the transport of the
mixture. The increasing price of energy makes it necessary to
achieve an increasing efficiency of the pumps, which explains
the interest in these experiments.
Koert, P., Miedema, S.A., (1981), "Report on the field excursion to the USA April 1981". MSc study, 1981, 54 pages, Report, Delft University of Technology.
Copyright: Dr.ir. S.A. Miedema
4. Excavation by the use of heavy Earth Moving Equipment.
4.1 Int roduct i on
The biggest civil engineering project in America at present is
the Tennessee-Tombigbee Waterway. This connection between the
Tennessee River and the Tombigbee River wi'll link ca. 25.750 km
(16000 miles) of navigable inland waterways with the ports on
the Gulf of Mexico.
Because of the boundary conditions imposed by environmental and
technical considerations the major part of the wOrk is being
done by means of the use of heavy earth moving equipment rather
than by dredging.
Although the original plans are much older. the project was
started only in 1972, partly as a result of delays caused by
protests by envi ronmental ists.
According to the official plans the 373 km (232 miles) long canal
should be completed in 1986. In fact the work is 18 months in
advance of schedule and it is anticipated that the canal will
be opened to navigation during 1984.
The total cost of the project is estimated at ca. $ 1,814.106
(1979 prices).
4.2 Description of the Tennessee-Tombigbee Waterway, Mississippi.
the tennessee-Tomb igbee Waterway can be d.i v i ded i hto three
sections:- River Section
- Canal Section
- Divide Section
The most important features of each section are described in the
following:
- 41 -
Koert, P., Miedema, S.A., (1981), "Report on the field excursion to the USA April 1981". MSc study, 1981, 54 pages, Report, Delft University of Technology.
Copyright: Dr.ir. S.A. Miedema
- 42 -
4 .2. 1 Rive r Se ct ion
A navigable channal of ca. 2.7 m (9 ft) deep and 91.4 m (300 ft)
wide is being dredged over a distance of 238 km (148 miles).
This canal runs from Demopolis, Alabama, to Amory, Missouri.
There are four locks and dams in this section. (Gainsville, Aliceville,
Columbus and Aberdeen). These can accommodate a difference in
height of ca. 35.7 m (117 ft).
At the time of our visit the Aberdeen lock and dam was almost
complete and as the construction pit was still dry the Ilunderwater"
construction work was still visible.
The lock chambe'rs are ca. 183 m (600 ft) long and 33.5 m (110 ft)
wide and wi I I accommodate a push tug with six barges. The lock
cycle is ca. 20 minutes.
The Columbus lock and dam was 99% ready and was already in use
for nav igat ion.
A special feature of the construction was the treatment of the
Lutew Clay, which was not only di.fficult to excavate but also
presented problems in relation to consol idation.
Columbus lock and dam.
Koert, P., Miedema, S.A., (1981), "Report on the field excursion to the USA April 1981". MSc study, 1981, 54 pages, Report, Delft University of Technology.
Copyright: Dr.ir. S.A. Miedema
4.2.2 Canal Section
Between Amory, Mississippi and Bay Springs, Tennessee, a canal
is being excavated by means of the use of heavy earth moving
equipment. This canal is ca. 71 km (44 miles) long and 91.4 m
(300 ft) wide and has five locks, (A,B,C,D and E), which together
accommodate a total difference in height of 42.7 m (140 ft).
Lock A.
4.2.3 Divide Section
Thi s section is one of the largest, 114.8.106 m3 (150.106 c.y.),
must be excavated,which is almost half the total amount which
must be moved during the work on the project and this wi 11 be
accompl ished by means of the use of heavy earth moving equipment.
- 43 -
Koert, P., Miedema, S.A., (1981), "Report on the field excursion to the USA April 1981". MSc study, 1981, 54 pages, Report, Delft University of Technology.
Copyright: Dr.ir. S.A. Miedema
- 44 -
In this section (Divide Cut) the canal is ca. 85.3 m (280 ft)
and 3.7 m (12 ft) deep. At Bay Springs a lock and dam accommodating
a difference in height of 25.6 m (84 ft) is under construction.
This lock differs from the 9 others with regard to the difference
in height.
Bay Springs lock and dam.
Koert, P., Miedema, S.A., (1981), "Report on the field excursion to the USA April 1981". MSc study, 1981, 54 pages, Report, Delft University of Technology.
Copyright: Dr.ir. S.A. Miedema
4.3 Earth moving equipment used
In addition to the usual heavy earth moving equipment, such
as for example scrapers, bulldozers, shovels and dump trucks
of very large capacity, a special piece of equipment, the
"Holland Loader l' , is in use.
The "Holland Loader 'l is pulled and/or pushed by two Caterpillar
bulldozers and makes a lengthwise cut while the material excavated
is transported into a dumptruck driving alongside by means of a
conveyor belt. The dumptruck then disposes of its load.
Three "Holland Loaders" are in operation in the Divide Section.
These can each attain a production of ca. 2754 m3/hr (3600 c.y./hr),
which is comparable to the production of a medium sized cutter
suction dredger.
The "Bolland Loader".
- 45 -
Koert, P., Miedema, S.A., (1981), "Report on the field excursion to the USA April 1981". MSc study, 1981, 54 pages, Report, Delft University of Technology.
Copyright: Dr.ir. S.A. Miedema
- 46 -
Koert, P., Miedema, S.A., (1981), "Report on the field excursion to the USA April 1981". MSc study, 1981, 54 pages, Report, Delft University of Technology.
Copyright: Dr.ir. S.A. Miedema
5. Environmental Aspects
Owing to the influence of environmental pressure groups a number
of environmental and dumping laws have been formulated, which
have contributed to the failure of a number of dredging companies.
The National Environmental Policy Act (NEPA) requires that an
HEnv i ronmenta 1 Impact Statement ll shoul d be prepared for every
project.
In this statement consideration must be given to following
environmental aspects:
- The effect of the proposed action upon the environment.
- The unavoidable unfavourable effects which the work wil 1 have on
the environment, during the period while work is in progress.
- The irreversible effects which the proposed action will have
on the natural environment.
- The relation between the short term effects on the environment
and the long term value of the proposed action.
- Possible alternatives to the paction.
The NEPA also provides a possibi lity to de ay a project for a
long period if there are fundamental environmental objections
to it. Work can only be commenced when all the conditions of
the NEPA have been satisfied. This means t in 0 ~ to meet
the requirements of the NEPA time consuming preliminary
is necessary
A number of other environmental and dumping laws exist, including
the IIFish and Wildlife Co-ordination Act", which requires that
before dredging activities can commence, the IIFish and Wildlife
Service ll must be consulted. The IIWater Pollution Control Act
Amendments ll, the IlMar i ne Protect ion 'Research & Sanctua ri es ll and
the "Ocean Dumping Act ll stipulate that only after a public
hearing, can permission be given for the discharge of dredge spoil
in navigable waterways, on spoi 1 s a.
Koert, P., Miedema, S.A., (1981), "Report on the field excursion to the USA April 1981". MSc study, 1981, 54 pages, Report, Delft University of Technology.
Copyright: Dr.ir. S.A. Miedema
Much administrative work is entailed in order to meet the requirements
of all these laws and the establ ishment of criteria relating to
the discharge of material into inland waters or the open sea is
by no means simple.
One such criterion has been established as a result of an agreement
between the U.S. Army Corps of Engineers and the Environmenta~
Protection Agency.
This specifies that the dredge spoil is not a pollutant when it
consists in the main of sand and gravel of a natural composition
and when the water in the neighbourhood of the discharge site
is suitable for fish, shellfish etc.
Koert, P., Miedema, S.A., (1981), "Report on the field excursion to the USA April 1981". MSc study, 1981, 54 pages, Report, Delft University of Technology.
Copyright: Dr.ir. S.A. Miedema
Bibliography Dr.ir. S.A. Miedema 1980-2010
1. Koert, P. & Miedema, S.A., "Report on the field excursion to the USA April 1981" (PDF in Dutch 27.2 MB). Delft University of Technology, 1981, 48 pages.
2. Miedema, S.A., "The flow of dredged slurry in and out hoppers and the settlement process in hoppers" (PDF in Dutch 37 MB). ScO/81/105, Delft University of Technology, 1981, 147 pages.
3. Miedema, S.A., "The soil reaction forces on a crown cutterhead on a swell compensated ladder" (PDF in Dutch 19 MB). LaO/81/97, Delft University of Technology, 1981, 36 pages.
4. Miedema, S.A., "Computer program for the determination of the reaction forces on a cutterhead, resulting from the motions of the cutterhead" (PDF in Dutch 11 MB). Delft Hydraulics, 1981, 82 pages.
5. Miedema, S.A. "The mathematical modeling of the soil reaction forces on a cutterhead and the development of the computer program DREDMO" (PDF in Dutch 25 MB). CO/82/125, Delft University of Technology, 1982, with appendices 600 pages.
6. Miedema, S.A.,"The Interaction between Cutterhead and Soil at Sea" (In Dutch). Proc. Dredging Day November 19th, Delft University of Technology 1982.
7. Miedema, S.A., "A comparison of an underwater centrifugal pump and an ejector pump" (PDF in Dutch 3.2 MB). Delft University of Technology, 1982, 18 pages.
8. Miedema, S.A., "Computer simulation of Dredging Vessels" (In Dutch). De Ingenieur, Dec. 1983. (Kivi/Misset).
9. Koning, J. de, Miedema, S.A., & Zwartbol, A., "Soil/Cutterhead Interaction under Wave Conditions (Adobe Acrobat PDF-File 1 MB)". Proc. WODCON X, Singapore 1983.
10. Miedema, S.A. "Basic design of a swell compensated cutter suction dredge with axial and radial compensation on the cutterhead" (PDF in Dutch 20 MB). CO/82/134, Delft University of Technology, 1983, 64 pages.
11. Miedema, S.A., "Design of a seagoing cutter suction dredge with a swell compensated ladder" (PDF in Dutch 27 MB). IO/83/107, Delft University of Technology, 1983, 51 pages.
12. Miedema, S.A., "Mathematical Modeling of a Seagoing Cutter Suction Dredge" (In Dutch). Published: The Hague, 18-9-1984, KIVI Lectures, Section Under Water Technology.
13. Miedema, S.A., "The Cutting of Densely Compacted Sand under Water (Adobe Acrobat PDF-File 575 kB)". Terra et Aqua No. 28, October 1984 pp. 4-10.
14. Miedema, S.A., "Longitudinal and Transverse Swell Compensation of a Cutter Suction Dredge" (In Dutch). Proc. Dredging Day November 9th 1984, Delft University of Technology 1984.
15. Miedema, S.A., "Compensation of Velocity Variations". Patent application no. 8403418, Hydromeer B.V. Oosterhout, 1984.
16. Miedema, S.A., "Mathematical Modeling of the Cutting of Densely Compacted Sand Under Water". Dredging & Port Construction, July 1985, pp. 22-26.
17. Miedema, S.A., "Derivation of the Differential Equation for Sand Pore Pressures". Dredging & Port Construction, September 1985, pp. 35.
18. Miedema, S.A., "The Application of a Cutting Theory on a Dredging Wheel (Adobe Acrobat 4.0 PDF-File 745 kB)". Proc. WODCON XI, Brighton 1986.
19. Miedema, S.A., "Underwater Soil Cutting: a Study in Continuity". Dredging & Port Construction, June 1986, pp. 47-53.
20. Miedema, S.A., "The cutting of water saturated sand, laboratory research" (In Dutch). Delft University of Technology, 1986, 17 pages.
21. Miedema, S.A., "The forces on a trenching wheel, a feasibility study" (In Dutch). Delft, 1986, 57 pages + software.
22. Miedema, S.A., "The translation and restructuring of the computer program DREDMO from ALGOL to FORTRAN" (In Dutch). Delft Hydraulics, 1986, 150 pages + software.
23. Miedema, S.A., "Calculation of the Cutting Forces when Cutting Water Saturated Sand (Adobe Acrobat 4.0 PDF-File 16 MB)". Basic Theory and Applications for 3-D Blade Movements and Periodically Varying Velocities for, in Dredging Commonly used Excavating Means. Ph.D. Thesis, Delft University of Technology, September 15th 1987.
24. Bakker, A. & Miedema, S.A., "The Specific Energy of the Dredging Process of a Grab Dredge". Delft University of Technology, 1988, 30 pages.
25. Miedema, S.A., "On the Cutting Forces in Saturated Sand of a Seagoing Cutter Suction Dredge (Adobe Acrobat 4.0 PDF-File 1.5 MB)". Proc. WODCON XII, Orlando, Florida, USA, April 1989. This paper was given the IADC Award for the best technical paper on the subject of dredging in 1989.
26. Miedema, S.A., "The development of equipment for the determination of the wear on pick-points" (In Dutch). Delft University of Technology, 1990, 30 pages (90.3.GV.2749, BAGT 462).
27. Miedema, S.A., "Excavating Bulk Materials" (In Dutch). Syllabus PATO course, 1989 & 1991, PATO The Hague, The Netherlands.
28. Miedema, S.A., "On the Cutting Forces in Saturated Sand of a Seagoing Cutter Suction Dredge (Adobe Acrobat 4.0 PDF-File 1.5 MB)". Terra et Aqua No. 41, December 1989, Elseviers Scientific Publishers.
29. Miedema, S.A., "New Developments of Cutting Theories with respect to Dredging, the Cutting of Clay (Adobe Acrobat 4.0 PDF-File 640 kB)". Proc. WODCON XIII, Bombay, India, 1992.
30. Davids, S.W. & Koning, J. de & Miedema, S.A. & Rosenbrand, W.F., "Encapsulation: A New Method for the Disposal of Contaminated Sediment, a Feasibility Study (Adobe Acrobat 4.0 PDF-File 3MB)". Proc. WODCON XIII, Bombay, India, 1992.
31. Miedema, S.A. & Journee, J.M.J. & Schuurmans, S., "On the Motions of a Seagoing Cutter Dredge, a Study in Continuity (Adobe Acrobat 4.0 PDF-File 396 kB)". Proc. WODCON XIII, Bombay, India, 1992.
32. Becker, S. & Miedema, S.A. & Jong, P.S. de & Wittekoek, S., "On the Closing Process of Clamshell Dredges in Water Saturated Sand (Adobe Acrobat 4.0 PDF-File 1 MB)". Proc. WODCON XIII, Bombay, India, 1992. This paper was given the IADC Award for the best technical paper on the subject of dredging in 1992.
33. Becker, S. & Miedema, S.A. & Jong, P.S. de & Wittekoek, S., "The Closing Process of Clamshell Dredges in Water Saturated Sand (Adobe Acrobat 4.0 PDF-File 1 MB)". Terra et Aqua No. 49, September 1992, IADC, The Hague.
34. Miedema, S.A., "Modeling and Simulation of Dredging Processes and Systems". Symposium "Zicht op Baggerprocessen", Delft University of Technology, Delft, The Netherlands, 29 October 1992.
35. Miedema, S.A., "Dredmo User Interface, Operators Manual". Report: 92.3.GV.2995. Delft University of Technology, 1992, 77 pages.
36. Miedema, S.A., "Inleiding Mechatronica, college WBM202" Delft University of Technology, 1992.
37. Miedema, S.A. & Becker, S., "The Use of Modeling and Simulation in the Dredging Industry, in Particular the Closing Process of Clamshell Dredges", CEDA Dredging Days 1993, Amsterdam, Holland, 1993.
38. Miedema, S.A., "On the Snow-Plough Effect when Cutting Water Saturated Sand with Inclined Straight Blades (Adobe Acrobat 4.0 PDF-File 503 kB)". ASCE Proc. Dredging 94, Orlando, Florida, USA, November 1994. Additional Measurement Graphs. (Adobe Acrobat 4.0 PDF-File 209 kB).
39. Riet, E. van, Matousek, V. & Miedema, S.A., "A Reconstruction of and Sensitivity Analysis on the Wilson Model for Hydraulic Particle Transport (Adobe Acrobat 4.0 PDF-File 50 kB)". Proc. 8th Int. Conf. on Transport and Sedimentation of Solid Particles, 24-26 January 1995, Prague, Czech Republic.
40. Vlasblom, W.J. & Miedema, S.A., "A Theory for Determining Sedimentation and Overflow Losses in Hoppers (Adobe Acrobat 4.0 PDF-File 304 kB)". Proc. WODCON IV, November 1995, Amsterdam, The Netherlands 1995.
41. Miedema, S.A., "Production Estimation Based on Cutting Theories for Cutting Water Saturated Sand (Adobe Acrobat 4.0 PDF-File 423 kB)". Proc. WODCON IV, November 1995, Amsterdam, The Netherlands 1995. Additional Specific Energy and Production Graphs. (Adobe Acrobat 4.0 PDF-File 145 kB).
42. Riet, E.J. van, Matousek, V. & Miedema, S.A., "A Theoretical Description and Numerical Sensitivity Analysis on Wilson's Model for Hydraulic Transport in Pipelines (Adobe Acrobat 4.0 PDF-File 50 kB)". Journal of Hydrology & Hydromechanics, Slovak Ac. of Science, Bratislava, June 1996.
43. Miedema, S.A. & Vlasblom, W.J., "Theory for Hopper Sedimentation (Adobe Acrobat 4.0 PDF-File 304 kB)". 29th Annual Texas A&M Dredging Seminar. New Orleans, June 1996.
44. Miedema, S.A., "Modeling and Simulation of the Dynamic Behavior of a Pump/Pipeline System (Adobe Acrobat 4.0 PDF-File 318 kB)". 17th Annual Meeting & Technical Conference of the Western Dredging Association. New Orleans, June 1996.
45. Miedema, S.A., "Education of Mechanical Engineering, an Integral Vision". Faculty O.C.P., Delft University of Technology, 1997 (in Dutch).
46. Miedema, S.A., "Educational Policy and Implementation 1998-2003 (versions 1998, 1999 and 2000) (Adobe Acrobat 4.0 PDF_File 195 kB)". Faculty O.C.P., Delft University of Technology, 1998, 1999 and 2000 (in Dutch).
47. Keulen, H. van & Miedema, S.A. & Werff, K. van der, "Redesigning the curriculum of the first three years of the mechanical engineering curriculum". Proceedings of the International Seminar on Design in Engineering Education, SEFI-Document no.21, page 122, ISBN 2-87352-024-8, Editors: V. John & K. Lassithiotakis, Odense, 22-24 October 1998.
48. Miedema, S.A. & Klein Woud, H.K.W. & van Bemmel, N.J. & Nijveld, D., "Self Assesment Educational Programme Mechanical Engineering (Adobe Acrobat 4.0 PDF-File 400 kB)". Faculty O.C.P., Delft University of Technology, 1999.
49. Van Dijk, J.A. & Miedema, S.A. & Bout, G., "Curriculum Development Mechanical Engineering". MHO 5/CTU/DUT/Civil Engineering. Cantho University Vietnam, CICAT Delft, April 1999.
50. Miedema, S.A., "Considerations in building and using dredge simulators (Adobe Acrobat 4.0 PDF-File 296 kB)". Texas A&M 31st Annual Dredging Seminar. Louisville Kentucky, May 16-18, 1999.
51. Miedema, S.A., "Considerations on limits of dredging processes (Adobe Acrobat 4.0 PDF-File 523 kB)". 19th Annual Meeting & Technical Conference of the Western Dredging Association. Louisville Kentucky, May 16-18, 1999.
52. Miedema, S.A. & Ruijtenbeek, M.G. v.d., "Quality management in reality", "Kwaliteitszorg in de praktijk". AKO conference on quality management in education. Delft University of Technology, November 3rd 1999.
53. Miedema, S.A., "Curriculum Development Mechanical Engineering (Adobe Acrobat 4.0 PDF-File 4 MB)". MHO 5-6/CTU/DUT. Cantho University Vietnam, CICAT Delft, Mission October 1999.
54. Vlasblom, W.J., Miedema, S.A., Ni, F., "Course Development on Topic 5: Dredging Technology, Dredging Equipment and Dredging Processes". Delft University of Technology and CICAT, Delft July 2000.
55. Miedema, S.A., Vlasblom, W.J., Bian, X., "Course Development on Topic 5: Dredging Technology, Power Drives, Instrumentation and Automation". Delft University of Technology and CICAT, Delft July 2000.
56. Randall, R. & Jong, P. de & Miedema, S.A., "Experience with cutter suction dredge simulator training (Adobe Acrobat 4.0 PDF-File 1.1 MB)". Texas A&M 32nd Annual Dredging Seminar. Warwick, Rhode Island, June 25-28, 2000.
57. Miedema, S.A., "The modelling of the swing winches of a cutter dredge in relation with simulators (Adobe Acrobat 4.0 PDF-File 814 kB)". Texas A&M 32nd Annual Dredging Seminar. Warwick, Rhode Island, June 25-28, 2000.
58. Hofstra, C. & Hemmen, A. van & Miedema, S.A. & Hulsteyn, J. van, "Describing the position of backhoe dredges (Adobe Acrobat 4.0 PDF-File 257 kB)". Texas A&M 32nd Annual Dredging Seminar. Warwick, Rhode Island, June 25-28, 2000.
59. Miedema, S.A., "Automation of a Cutter Dredge, Applied to the Dynamic Behaviour of a Pump/Pipeline System (Adobe Acrobat 4.0 PDF-File 254 kB)". Proc. WODCON VI, April 2001, Kuala Lumpur, Malaysia 2001.
60. Heggeler, O.W.J. ten, Vercruysse, P.M., Miedema, S.A., "On the Motions of Suction Pipe Constructions a Dynamic Analysis (Adobe Acrobat 4.0 PDF-File 110 kB)". Proc. WODCON VI, April 2001, Kuala Lumpur, Malaysia 2001.
61. Miedema, S.A. & Zhao Yi, "An Analytical Method of Pore Pressure Calculations when Cutting Water Saturated Sand (Adobe Acrobat PDF-File 2.2 MB)". Texas A&M 33nd Annual Dredging Seminar, June 2001, Houston, USA 2001.
62. Miedema, S.A., "A Numerical Method of Calculating the Dynamic Behaviour of Hydraulic Transport (Adobe Acrobat PDF-File 246 kB)". 21st Annual Meeting & Technical Conference of the Western Dredging Association, June 2001, Houston, USA 2001.
63. Zhao Yi, & Miedema, S.A., "Finite Element Calculations To Determine The Pore Pressures When Cutting Water Saturated Sand At Large Cutting Angles (Adobe Acrobat PDF-File 4.8 MB)". CEDA Dredging Day 2001, November 2001, Amsterdam, The Netherlands.
64. Miedema, S.A., "Mission Report Cantho University". MHO5/6, Phase Two, Mission to Vietnam by Dr.ir. S.A. Miedema DUT/OCP Project Supervisor, 27 September-8 October 2001, Delft University/CICAT.
65. (Zhao Yi), & (Miedema, S.A.), "
" (Finite Element Calculations To Determine The Pore Pressures When Cutting Water
Saturated Sand At Large Cutting Angles (Adobe Acrobat PDF-File 4.8 MB))". To be published in 2002.
66. Miedema, S.A., & Riet, E.J. van, & Matousek, V., "Theoretical Description And Numerical Sensitivity Analysis On Wilson Model For Hydraulic Transport Of Solids In Pipelines (Adobe Acrobat PDF-File 147 kB)". WEDA Journal of Dredging Engineering, March 2002.
67. Miedema, S.A., & Ma, Y., "The Cutting of Water Saturated Sand at Large Cutting Angles (Adobe Acrobat PDF-File 3.6 MB)". Proc. Dredging02, May 5-8, Orlando, Florida, USA.
68. Miedema, S.A., & Lu, Z., "The Dynamic Behavior of a Diesel Engine (Adobe Acrobat PDF-File 363 kB)". Proc. WEDA XXII Technical Conference & 34th Texas A&M Dredging Seminar, June 12-15, Denver, Colorado, USA.
69. Miedema, S.A., & He, Y., "The Existance of Kinematic Wedges at Large Cutting Angles (Adobe Acrobat PDF-File 4 MB)". Proc. WEDA XXII Technical Conference & 34th Texas A&M Dredging Seminar, June 12-15, Denver, Colorado, USA.
70. Ma, Y., Vlasblom, W.J., Miedema, S.A., Matousek, V., "Measurement of Density and Velocity in Hydraulic Transport using Tomography". Dredging Days 2002, Dredging without boundaries, Casablanca, Morocco, V64-V73, 22-24 October 2002.
71. Ma, Y., Miedema, S.A., Vlasblom, W.J., "Theoretical Simulation of the Measurements Process of Electrical Impedance Tomography". Asian Simulation Conference/5th International Conference on System Simulation and Scientific Computing, Shanghai, 3-6 November 2002, p. 261-265, ISBN 7-5062-5571-5/TP.75.
72. Thanh, N.Q., & Miedema, S.A., "Automotive Electricity and Electronics". Delft University of Technology and CICAT, Delft December 2002.
73. Miedema, S.A., Willemse, H.R., "Report on MHO5/6 Mission to Vietnam". Delft University of Technology and CICAT, Delft Januari 2003.
74. Ma, Y., Miedema, S.A., Matousek, V., Vlasblom, W.J., "Tomography as a Measurement Method for Density and Velocity Distributions". 23rd WEDA Technical Conference & 35th TAMU Dredging Seminar, Chicago, USA, june 2003.
75. Miedema, S.A., Lu, Z., Matousek, V., "Numerical Simulation of a Development of a Density Wave in a Long Slurry Pipeline". 23rd WEDA Technical Conference & 35th TAMU Dredging Seminar, Chicago, USA, june 2003.
76. Miedema, S.A., Lu, Z., Matousek, V., "Numerical simulation of the development of density waves in a long pipeline and the dynamic system behavior". Terra et Aqua, No. 93, p. 11-23.
77. Miedema, S.A., Frijters, D., "The Mechanism of Kinematic Wedges at Large Cutting Angles - Velocity and Friction Measurements". 23rd WEDA Technical Conference & 35th TAMU Dredging Seminar, Chicago, USA, june 2003.
78. Tri, Nguyen Van, Miedema, S.A., Heijer, J. den, "Machine Manufacturing Technology". Lecture notes, Delft University of Technology, Cicat and Cantho University Vietnam, August 2003.
79. Miedema, S.A., "MHO5/6 Phase Two Mission Report". Report on a mission to Cantho University Vietnam October 2003. Delft University of Technology and CICAT, November 2003.
80. Zwanenburg, M., Holstein, J.D., Miedema, S.A., Vlasblom, W.J., "The Exploitation of Cockle Shells". CEDA Dredging Days 2003, Amsterdam, The Netherlands, November 2003.
81. Zhi, L., Miedema, S.A., Vlasblom, W.J., Verheul, C.H., "Modeling and Simulation of the Dynamic Behaviour of TSHD's Suction Pipe System by using Adams". CHIDA Dredging Days, Shanghai, China, november 2003.
82. Miedema, S.A., "The Existence of Kinematic Wedges at Large Cutting Angles". CHIDA Dredging Days, Shanghai, China, november 2003.
83. Miedema, S.A., Lu, Z., Matousek, V., "Numerical Simulation of the Development of Density Waves in a Long Pipeline and the Dynamic System Behaviour". Terra et Aqua 93, December 2003.
84. Miedema, S.A. & Frijters, D.D.J., "The wedge mechanism for cutting of water saturated sand at large cutting angles". WODCON XVII, September 2004, Hamburg Germany.
85. Verheul, O. & Vercruijsse, P.M. & Miedema, S.A., "The development of a concept for accurate and efficient dredging at great water depths". WODCON XVII, September 2004, Hamburg Germany.
86. Miedema, S.A., "THE CUTTING MECHANISMS OF WATER SATURATED SAND AT SMALL AND LARGE CUTTING ANGLES". International Conference on Coastal Infrastructure Development - Challenges in the 21st Century. HongKong, november 2004.
87. Ir. M. Zwanenburg , Dr. Ir. S.A. Miedema , Ir J.D. Holstein , Prof.ir. W.J.Vlasblom, "REDUCING THE DAMAGE TO THE SEA FLOOR WHEN DREDGING COCKLE SHELLS". WEDAXXIV & TAMU36, Orlando, Florida, USA, July 2004.
88. Verheul, O. & Vercruijsse, P.M. & Miedema, S.A., "A new concept for accurate and efficient dredging in deep water". Ports & Dredging, IHC, 2005, E163.
89. Miedema, S.A., "Scrapped?". Dredging & Port Construction, September 2005. 90. Miedema, S.A. & Vlasblom, W.J., " Bureaustudie Overvloeiverliezen". In opdracht
van Havenbedrijf Rotterdam, September 2005, Confidential. 91. He, J., Miedema, S.A. & Vlasblom, W.J., "FEM Analyses Of Cutting Of Anisotropic
Densely Compacted and Saturated Sand", WEDAXXV & TAMU37, New Orleans, USA, June 2005.
92. Miedema, S.A., "The Cutting of Water Saturated Sand, the FINAL Solution". WEDAXXV & TAMU37, New Orleans, USA, June 2005.
93. Miedema, S.A. & Massie, W., "Selfassesment MSc Offshore Engineering", Delft University of Technology, October 2005.
94. Miedema, S.A., "THE CUTTING OF WATER SATURATED SAND, THE SOLUTION". CEDA African Section: Dredging Days 2006 - Protection of the coastline, dredging sustainable development, Nov. 1-3, Tangiers, Morocco.
95. Miedema, S.A., "La solution de prélèvement par désagrégation du sable saturé en eau". CEDA African Section: Dredging Days 2006 - Protection of the coastline, dredging sustainable development, Nov. 1-3, Tangiers, Morocco.
96. Miedema, S.A. & Vlasblom, W.J., "THE CLOSING PROCESS OF CLAMSHELL DREDGES IN WATER-SATURATED SAND". CEDA African Section: Dredging Days 2006 - Protection of the coastline, dredging sustainable development, Nov. 1-3, Tangiers, Morocco.
97. Miedema, S.A. & Vlasblom, W.J., "Le processus de fermeture des dragues à benne preneuse en sable saturé". CEDA African Section: Dredging Days 2006 - Protection of the coastline, dredging sustainable development, Nov. 1-3, Tangiers, Morocco.
98. Miedema, S.A. "THE CUTTING OF WATER SATURATED SAND, THE SOLUTION". The 2nd China Dredging Association International Conference & Exhibition, themed 'Dredging and Sustainable Development' and in Guangzhou, China, May 17-18 2006.
99. Ma, Y, Ni, F. & Miedema, S.A., "Calculation of the Blade Cutting Force for small Cutting Angles based on MATLAB". The 2nd China Dredging Association
International Conference & Exhibition, themed 'Dredging and Sustainable Development' and in Guangzhou, China, May 17-18 2006.
100. ,"" (download). The 2nd China Dredging
Association International Conference & Exhibition, themed 'Dredging and Sustainable Development' and in Guangzhou, China, May 17-18 2006.
101. Miedema, S.A. , Kerkvliet, J., Strijbis, D., Jonkman, B., Hatert, M. v/d, "THE DIGGING AND HOLDING CAPACITY OF ANCHORS". WEDA XXVI AND TAMU 38, San Diego, California, June 25-28, 2006.
102. Schols, V., Klaver, Th., Pettitt, M., Ubuan, Chr., Miedema, S.A., Hemmes, K. & Vlasblom, W.J., "A FEASIBILITY STUDY ON THE APPLICATION OF FUEL CELLS IN OIL AND GAS SURFACE PRODUCTION FACILITIES". Proceedings of FUELCELL2006, The 4th International Conference on FUEL CELL SCIENCE, ENGINEERING and TECHNOLOGY, June 19-21, 2006, Irvine, CA.
103. Miedema, S.A., "Polytechnisch Zakboek 51ste druk, Hoofdstuk G: Werktuigbouwkunde", pG1-G88, Reed Business Information, ISBN-10: 90.6228.613.5, ISBN-13: 978.90.6228.613.3. Redactie: Fortuin, J.B., van Herwijnen, F., Leijendeckers, P.H.H., de Roeck, G. & Schwippert, G.A.
104. MA Ya-sheng, NI Fu-sheng, S.A. Miedema, "Mechanical Model of Water Saturated Sand Cutting at Blade Large Cutting Angles", Journal of Hohai University Changzhou, ISSN 1009-1130, CN 32-1591, 2006. 绞刀片大角度切削水饱和沙的力学模型, 马亚生[1] 倪福生[1] S.A.Miedema[2], 《河海大学常州分校学报》-2006年20卷3期 -59-61页
105. Miedema, S.A., Lager, G.H.G., Kerkvliet, J., “An Overview of Drag Embedded Anchor Holding Capacity for Dredging and Offshore Applications”. WODCON, Orlando, USA, 2007.
106. Miedema, S.A., Rhee, C. van, “A SENSITIVITY ANALYSIS ON THE EFFECTS OF DIMENSIONS AND GEOMETRY OF TRAILING SUCTION HOPPER DREDGES”. WODCON ORLANDO, USA, 2007.
107. Miedema, S.A., Bookreview: Useless arithmetic, why environmental scientists can't predict the future, by Orrin H. Pilkey & Linda Pilkey-Jarvis. Terra et Aqua 108, September 2007, IADC, The Hague, Netherlands.
108. Miedema, S.A., Bookreview: The rock manual: The use of rock in hydraulic engineering, by CIRIA, CUR, CETMEF. Terra et Aqua 110, March 2008, IADC, The Hague, Netherlands.
109. Miedema, S.A., "An Analytical Method To Determine Scour". WEDA XXVIII & Texas A&M 39. St. Louis, USA, June 8-11, 2008.
110. Miedema, S.A., "A Sensitivity Analysis Of The Production Of Clamshells". WEDA XXVIII & Texas A&M 39. St. Louis, USA, June 8-11, 2008.
111. Miedema, S.A., "An Analytical Approach To The Sedimentation Process In Trailing Suction Hopper Dredgers". Terra et Aqua 112, September 2008, IADC, The Hague, Netherlands.
112. Hofstra, C.F., & Rhee, C. van, & Miedema, S.A. & Talmon, A.M., "On The Particle Trajectories In Dredge Pump Impellers". 14th International Conference Transport & Sedimentation Of Solid Particles. June 23-27 2008, St. Petersburg, Russia.
113. Miedema, S.A., "A Sensitivity Analysis Of The Production Of Clamshells". WEDA Journal of Dredging Engineering, December 2008.
114. Miedema, S.A., "New Developments Of Cutting Theories With Respect To Dredging, The Cutting Of Clay And Rock". WEDA XXIX & Texas A&M 40. Phoenix Arizona, USA, June 14-17 2009.
115. Miedema, S.A., "A Sensitivity Analysis Of The Scaling Of TSHD's". WEDA XXIX & Texas A&M 40. Phoenix Arizona, USA, June 14-17 2009.
116. Liu, Z., Ni, F., Miedema, S.A., “Optimized design method for TSHD’s swell compensator, basing on modelling and simulation”. International Conference on Industrial Mechatronics and Automation, pp. 48-52. Chengdu, China, May 15-16, 2009.
117. Miedema, S.A., "The effect of the bed rise velocity on the sedimentation process in hopper dredges". Journal of Dredging Engineering, Vol. 10, No. 1 , 10-31, 2009.
118. Miedema, S.A., “New developments of cutting theories with respect to offshore applications, the cutting of sand, clay and rock”. ISOPE 2010, Beijing China, June 2010.
119. Miedema, S.A., “The influence of the strain rate on cutting processes”. ISOPE 2010, Beijing China, June 2010.
120. Ramsdell, R.C., Miedema, S.A., “Hydraulic transport of sand/shell mixtures”. WODCON XIX, Beijing China, September 2010.
121. Abdeli, M., Miedema, S.A., Schott, D., Alvarez Grima, M., “The application of discrete element modeling in dredging”. WODCON XIX, Beijing China, September 2010.
122. Hofstra, C.F., Miedema, S.A., Rhee, C. van, “Particle trajectories near impeller blades in centrifugal pumps. WODCON XIX, Beijing China, September 2010.
123. Miedema, S.A., “Constructing the Shields curve, a new theoretical approach and its applications”. WODCON XIX, Beijing China, September 2010.
124. Miedema, S.A., “The effect of the bed rise velocity on the sedimentation process in hopper dredges”. WODCON XIX, Beijing China, September 2010.