208 NOTES.

NOTES.

INDEX TO NOTES. h3ECHANICAL PROGRESS IN MARINE ENGINEEalNG DURING 1946.

-Shipbuilding and Marine-Engine Builder, Januar? , 1917

-Pacific Marine Review, January, 1947 SELECTION OF MARINE DIESEL DRIVES.

I

ATOMIC EPJERGY AND ITS APPLICATIONS. -The Institute of Fuel, December, 1946

,I( 5

NOTES ON SUBMARINE DESIGN.

ROLLER BEARINGS IN STERN TUBES.

DEAUMIDIFICATION PROTECTS U. S. NAVY'S INACTIVE FLEET.

RUSTING CHARACTERISTICS OF TURBINE LUBRICATING OILS.

ENGINEERING LESSONS AND GAINS OF THE RECENT YEARS.

--Mechanical Engineering, March, 1047

-Motor Ship, August, 1946.

-Heating, Piping and Air Conditioning, March, 1946.

-Mechanical Engineering, October, 1946 .

-Westinghouse Engineer, January, 1947.

NOTES. ’ioz

TECWNIC,\I. PROGRESS IF: MARIKE ENGiNEBRITG DURING 1946.

This interesting summary ot the proqess made in Great Britain over the past year in Marine En ‘neerin is reprinted from the January 1941 issue of the “Shipbuilding and Garine-Engine Builder.” The article does not cover the field in detail, but will aeme as a guide to further reading for those who are interested in British developments along a particular line. For those who are interested in the broad picture i t is excellent reading.

INTRODUCTION. Certain leading developments always stand out when the preparation of

this annual survey has to be considered. &What are they, so far as 1946 is concerned? Probably, no two marine engiseers would give the unie emphasis in replying to this question, but, in our view, the followin are the features which, in broad outline. provide the framework within whict a more detailed picture may bc presented; the ousting of coal as a maritime fuel; increasing practical interest in gas turbines; the successful redivivus of low-grade boiler- quality fuel oil as a fuel for Diesel engines; the progress made in connection with geared steam turbines and water-tube boilers for tonnage which, before the war, would, in all probability, have been equipped with Diesel engines; and the completion of several important British-built turbo-electric vessels.

From a national, rather than a technical, paint of view the entry into norma! transatlantic service of the Cunard White Star liner Queen Elzmbelh cannot be overlooked in this survey, for she is a “new” ship so far as the technical Press is concerned. Broadly similar to her famous sister, the Queen &fury, in so far as main-machinery characteristics a r e concerned, the Quee?t Elizabeth is notc- worthy in that she has no more than 12 Yarrow water-tube boilers for her normal service power of 160,000 S.H.P. I t is certain, moreover, that thesc large boilers could provide steam for a considerably greater output than mentioned, and which is sufficient to give a service speed of about 28% k Service experience with these boilers--as with the main and auxiliary ma cry-has been most satisfactory, and they have been further improved by the introduction of external circulating pipe5 (about 6 inches in diameter) which connect the upper and lower drums.

In regard to the main turbines, the same interesting four-pinion, fourcasing i.iyout, with a form of nodal drive, which proved so 3uccessful in the earlier Queen, has been adopted in the more recent ship; and performance r ca rdz certainly justify the choice, Both ships played a strenuous part during thc war, and their machinery and boilers were fully equal to the demands made on them.

I t is interesting to conjecture what might have been the behavior of some of the German liners of the immediate pre-war era had they been called upon to undertake such arduous duties-and with a minimum of attention. I t is, in our view, improbable that their advanced turbine machinery and u l t r ~ - modern boiler plants would have given such a good account of theinselves; cvperience with both naval and mercantile vessels suggests this, and i t seems certain that the overall operational economy, allowing for repair and main- tenance charges, would scarcely have been so favorable. Though the Quemr mdy appear conventional to Continental marine engineers-and even perhaps too conservative-they have clearly k e n built to a machinery specification which, for onerous service and sustained reliability, is admirable.

Coal as a fuel for ships has become a mainly academic Interest to marine engineers-and a luxury for shipowners. Costing today about MS. Od. per tor, in the Port of London, i t has,ceased to be a “paying proposition”; boiler oil can be had in the sanie area for about 77s. Od. per tow-figures which make it superfluous to seek technical ex lanations for the present popularity of oil- burning ships with erstwhile coafusing owners. With even greater emphasis, thc present-day popularity of the motorship draws af,tention to the unhappy, une,iay position of our coal industry ws-n-ens shipping. How can an owner of coasting ships, for iastance, conteniplate placing orders for coal-burning veb-

210 10 rm.

sels, relatively attractive in first cost as the)- may be? The latest -anti I ' J . I - ~ - cst--"flat-iron" collier, designed for service between Xorth-East ports 3nti the 'Ihames, has been equipped with Diesel propelling machinery for verb. sound reasons; and i t seems unlikely that coal-using steam installations x-ill reappear for this service when more vessels of the type are ordered.

one British shipowning company, for, in 1946, i t was announced that the :lnglo- Sason Petroleum Co., Ltd., had ordered a 1200-S.H.P. set for instn1l;ition i n ii Diesel-electric oil-tank ship now being built on the Tyne. The vessel, <i5 originally conceived, is of considerable technical interest, for she is to be pro- pelled by four Sulzer four-stroke cycle Diesel engines directly couplctl to generators which will supply electric energy to a single propelling motor. 'I'he engines are to be pressure-charged on the Biichi system, and it is worthy of note that this will be the first large ship to be propelled by Sulzer four-stroke cycle engines. The ultimate intention, it is inderstood, is to replace one of t h c Sulzer-engine sets by a gas turbine and generator, for which the British 'l'homson-Houston Co., Ltd., are to be responsible. In this w a y , ;i uscful amount of sea experience should be accuniulated, and, in the event of rlitticultv bring experienced, the comparatively-high normal speed of the vrssel will suffer only slight reduction. This is a development concerning which further news will be awaited with interest, perhaps even impitience, by xll who helieve-as does this journal-that the gas turbine has a n important iuture i n the sphere of ship propulsion.

Other developments in connection with gas turbines are envisaged by the Anglo-Saxon technical experts, and their two-unit turbo-electric inst;illation-. will provide them with a safe basis for a more ambitious experiment than t h a t just referred to. I t is planned to substitute for onc of the steam turh~i- alternator sets in a Helicina-class ship, a gas turbine of equivalent net outpat-- assuming, of course. that the smaller trial unit in the Diesel-electric ship proves wccessfu!. I'his more ambitious scheme will be watched with gre,tt interest, as the plant will have an output capacity likely to appeal to i n a i i . - onmers. Here, again, if for any reason the gas turbine should have to be s h u i down, the vessel will be able to proceed on the single steam turbine-driwn alternator-a comforting consideration which will doubtless acccler;ilc the csperimen t.

An interesting - if brief-allusion to marine gas turbines W.IS m : ~ d e by Lord Aberconway a t the recent launch of the Cunard White Star line:. 6 fcd iv from the Clydebank shipyard of Messrs. john Broivn Sr Co., Ltd. T\vo set> of turbines are now being built in their shops and a third unit is on the cl awin : board. The completion of the first of these experimental sets (concerning \vhich no information has so far been released) will be awaited with Iccen anticipation. Meanwhile, developments in Switzerland are proceeding. if more slowly, on the marine side. Messrs. Brown, Boveri & Co., Ltd., at one tini- had high hope of installing a gas turbine for main propulsion i n a "Liberty" ship, but the project was eventually abandoned. The Swiss firm have, hov;- ever, completed a number of stationary as turbines during thc past )'ear, including some of considerable size, and t i ey have put forward a number of marine proposals. Havin regard to their unique experience in connection with the gas turbine and tfeit sound marine engineering reputation, one may hazard the guess that they will not have to wait much IonRer for their first marine order. Like many British marine engincers, they favor the Reared layout rather than the gas turbine-electric system: and adjustable-pitch p:-o- pellers figure in most of their proposals.

The most serious demerit of the gas turbine for marine duty is the Iargc. size of the associated air heaters and recuperators, and the considerable a inomt of largediameter pipe work involved. The latter feature, i t seems, \vill be most difficult to improve, but we may hopefully look for rapid advances in the design of air heaters and recuperators. Indeed, progress m u s t be made here if gas turbines are to attract owners to the extent which their technical potentialities promise. Messrs. Sulzer Brothers are one of the niany firms engaged on the whole broad subject, a n d , i n their development work, t h i s

Practical interest in the gas turbine has already been displayed

questiori of t l i r escessive size of the ancillary uaits is being kept well t o iht . fore. A good thermal efficiency is claimed for thair design-superior to thc best marine turbine ractice at all loads, they assert. A 7000-S.H.P. instalk- tion is almost ready fk test, and we shall, no doubt, he in a position to desc-rih(: it in due course. to improve their standard range of marine and other Diesel engines. and to &velop tlicir "power-gas" and high-supercharge processes, which promise interesting results.

Other British companies have been mentioned during the past year in coii- nection with marine gas turbines; and it is noteworthy that not a few of thein have substantial interests in the construction of turbo-generators for shorc duties. Of these firms, only Messrs. C. A. Parsons ,U; Co., Ltd., reachec! the point a t which they permitted details of a n actual experimental set to be released. The Parsons open-cycle gas-turbine plant of 500 (available) horsc- power is a straightforward machine which has now done a considerable amouni of running. According to present indications, it scerns unlikely that the design tvi l l be developed for marine work-although the fact must not be ovcrlooltcd that Xlessrs. C. A. Parsons & Company supplied the turbo-electric niacliincry for t h e ne\r C':inndiui Pacific Beaurr-class vessels.

PAM ETR AD A .

S o doubt, thc espcrience gained in operating this gris-turlJinc pl l i i i t i v i l l be a\vail:it)le for irivestigation by the Parsons and hllarine Engineering Turbine Research and 1)evelopment Association (Pametrada), now i n active operatioil at \Vallsend under the immediate direction of Dr. T. W. F. Brown. T h e :issociation, of course, have their own plans for ninrine gas turbines, though the form their design will take cannot be discussed a t present; but, with thc ample resources and growing testing facilities at their disposd, P:iriictr~:dCi diould be able to offer to sponsors a sound design much more quickly ti would otherwise br possible. The Association will also, of course, COT? undoubted benefits on member firms in regard to steam turbines of iinprox rlesigri and performance.

:\inong i.he items of the research prograin c;trried out largely on the prciiii nf XIessrs. C. A. Parsons and Co., Ltd., while the Association were awaitii1i; the completion of their own buildings and the acquisition of research a p p ~ r n t ti>, re the following:--. rl stress analysis, b y photo-elastic means, of certain th'pes of straddle-:-cinr

forms of turbine blading 'was carried out, in conjunction with tensile t w t s oii ,icttinI ~naterials similar to those U W ~ I in the blades x i t i rotors, to detcrniiiiL, the best proportions of the bearing surfaces of 1 he roots.

Tests on a research turbine incorporating reaction blading having h11- nosed entry were carried out . These tests covered both end-tightened iincl radial-clearance hlnding. Steaming tests, corrcsponding to varying ratios O{ blade speed to steam speed, enabled efficiency figures to be determined.

A spray-tester rig of Pametrada design was k s t erected and useti i n theii research building. Experiments to determine the quality of the spra). f rom it variety of nozzles supplied with fuel oil of varying grades w w c carried oiii. and the Association have thereby added considerably to their design dat.1 for. gas-turbine sprayers using heavy fuel oil.

Preliminary experiments have been imdc on the strength of the fastenin, of built-up diaphragnis, and these are to be amplified by a further wries -xperinients in the near future.

Equipment for the study of vibration phenoriiena has been developed, 1 hi: !.ticst iiistrunieriis and electronic techniques being incorporated.

On the metallurgical side, there has been close liaison with various forp,c; producing high-temprratnre materials, and data regarding the propcriies ?f ii1;lterials to lie used in inariiic gas-turbine design have been accurnuLitixi. 'l'he question of stcani-turbine materials has also beer1 studied during 19-I(!.

'~'CRIIO-ELECTRIC INSTALI.ATTONS.

hieanwhile, this progressive firm are continuin

In planning this survc'y, we as1;ed a n u m %>. iiicii, in their opinion, \';ere the most iritcr

i of marine engincere to s! . ting ;ind sipnilicant macliiiit

212 NOTES.

installations of the past year, a d , without exception, those of the nen b'eavcr- class cargo liners of the Canadian Pacific fleet were singled out for speciai comment. Many readers will, no doubt, concur in this assessment. A reheat cycle incorporating a single turb-alternator unit of considerable size, and using steani at a'pressure of 650 pounds per square inch and a temperature of 850 degrees F,, is somewhat exceptional, to say the least; bu t the technical boldness of the designers of the Beaverdell and her sister ships does xfot end there. Steam, it may be recalled, is supplied by a single BabcocG-Johnson boiler, and this unit incorporateets reheatirt as well as superheating sections. A Howden-Johnson combined fire-tube ancfwatet-tube auxiliary boiler gener- ates saturated steam for dorhestic services, make-up feed, and turbine-gland and fuel-oil heatln duties. Not the least interesting aspect of the installation is the manner in wiich one of the comparativelyIatge Allen LXesel-generating sets is coupled ih tandem tb a Parsons alternator and an Allen D.C. machine, so that , in the event of the main turbo-alternator bein out of commission, the Allen-Parsons Diesel-alternator set can supply suf&ent' energy to the propelling motor to keep steerage way on the vessel; a speed of about 6% knots was obtained on trial with this arrangement.

The new Beaver ships have performed well in service and have shown very good fuel economy. Their machinery installations and the performance of the latter fortqed the subject of a recent, paper presented by Mr. A W. Davis, B.Sc., to the North-+t Co5st Institution of Engineers and Shipbuilders, and A l l who&& further information on a high] interesting development in marine machinery are urged to study i t ; they will f!nd in it much to stimulate thought.

Another interesting turbo-electric installation completed in this country in recent months is that of the oibtank ship Hr$Uina, The B.T.H. main turbo- alternator equipment of this vessel represwts a more conventional solution of the ropulsion problem for a large hi h powered single-screw ship than does tha t orthe. Baauer vessels. Her owners?& AngloSaxon Petroleum Co., Ltd.) prefer to have two turbo-alternators, and for such an exacting service, the choice h a much to commend it. Moreover, if the position in regard to freight ram d w not justify the high speed of which the vessel is capable, one turbo- alternatar can be shut down and a more economical (but s t i l l comparatively high) speed maintained, with one set operating a t optimum efficiency. The boilers in the Helicina do not incorporate reheating units, a6 do those in the Heaver ships, but it is l a n d to employ a heavy asphaltic-base fuel oil a5 soon as supplies are s u c i as to make this interesting experiment possible.

In connection with this development, the Anglo-Saxon Company sponsored experiments (conducted at the works of Messrs. Swinney Brothers, Ltd , Motpeth), designed to investigate the burning of low-grade asphalt-base fue! oil under marine boilers. While this may not be such a difficult undertaking as that presented by the Awiculu experiment-in which a similar problem was tackled in connection with the use of low-grade fuel in a Diesel engine- the utilization of a hi hly viscous petroleum residue as boiler fuel involves a number of practical cfifficulties which have been solved to the owners' satis- faction. It had been intended to operate the recently completed Helicina on such fuel oil, but, at the time of her trials, supplies were not available in this country. In due course, the Anglo-Saxon Petroleum Co., Ltd., will, no doubt, give an amount of their experience with this heavier fuel oil, the satisfactory employment of which under marine boilers should represent an important practical and economic development.

GEARED STEAM TURBINES. The two-casing steam-turbihe installation, with double-reduction gearing,

has made notable headway in Britain during recent years, and further orders for such machinery were placed during the period under review. The modern form of double-reduction gearing constitutes a reliable piece of mechanism which has effectively lived down the evil reputation the principle earned for itself after the first world war. Much has been learned concerning the need for accuracy in gear-cutting and gearing design generally, and invedgation

and ~ m ~ ~ r o v e m e n t dre not standing stiil, despite the Latisfactory stage v I ~ I L I I 11,ib now bceii Ieachcd.

At one time, some marine engineers expressed doubts as to the wisdom of adopting astern turbines m one casing only, but service experience has shon n the practice to be satisfactory in nunierous instances. Clearly, there is n o objection to the incarporation of astern blading in both casings, if the particular conditions &I1 for larger astern power, and such sets are, in fact, being built

With the increasin steam temperatures envisaeed in the search for still better performances from geared-turbine installations, astern elements are bound, almost inevitably, to become an increasing worrk to the desigaei- Recent information concerning their Iatest designs shows that, in the imme- diate pre-war period, German designers were alive to the difficulties. Spe- cialists in this country are likely to offer better designs which should makc for high reliability in the largest geared-turbine installations having astern sec- tions taking steam at temperatures hitherto considered more suitable for turbo-electric plants.

An alternative solution to the reversing roblem in its relationship to modern steam conditions is the adoption of rnecfanical reversing q r . That this I < not a n im racticable ropopat was shown in the p a r by d. Davis, to which reference {as a l rmdy teen made. The author bne y described such a scheme, now in course of development, and th6 drawing which accompanied his CY osi tion showed i t to be not only ingenious, but also, so far as could be ju&edI practical. A large-scare experiment would afford confirmation of its value at sea, and it is hoped that a suitable opportunity may be found to incorporate the system in a ship. Clearly, the scheme has great potentialities for use in association with gas turbines, a$ well as with steam turbines, and this fact will no doubt encourage its sponsors to press forward vigoroysly with it. development. I t is no exaggeration to say that this problem of astern powei i b among the most important of the moment.

RPCIPR~CATING STEAM ENGINES. Reference has been made in previous annual surveys to the Gotaverken

quadruple-expansion marine steam engine, in which noteworthy econoniv i n steam consumption is achieved without radical departure lrom conventionalit) in the mechanical sense. The design does, however, reveal keen appreciatior, of the factors conducive to good steam consumption in a reciprocating engiiw of moderate size, and very satisfactory results have been achieved without rtxourse to refinements which entail high manufacturing cost or undue com- blication. The prescnt survey is scarcely the plaoe t o discuss the general fe,~tures of the desiqn, but the latest development-perhaps an inevitable one-is the association with this engine of the Gotaverken steam turbo- compressor.

One or two such installations have been built during the past year, and, not unexpectedly, the results have been excellent. With coal as fuel, and with reheater and turbo-compressor in operation, such an engine, of 1500 1.H P ~

has returned an all-purpose fuel consumption of 0.805 pound per I.H.P. pc.r hour-a remarkably fine performance. A t the present juncture, when oil is generally considered to be the only practicable marine fuel, it is of interest to note that this rformance represents a specific consumpfion of 0.625 pound of oii per s.H.€? The moderate steam pressures and tenrperatures adopted for these engines are such as can be obtained with Scotch boilers, and installa- tions of this design would appear to have considerable intcrest for the owner of medium-size and moderate-power tonnage, as an alternative to Diec.e! machinery.

I t would be interesting to see what results could he obtained from an instal- lation of this kind, supplemented by cornbustibn-chamber superheaters capablt of giving a steam temperature in the neighborhood of 7.50 degrees F.. inste.iti of the moderate figure of about 600 degxes F. employed in the vessel.; for \%hi& results have just been ouoted.

\YC IIJVC c~~ i i i i i e~ i t (~ t i icdesign has reached, siderable nuni lxr oi

firms in this country who now hold a license in respect of the Doxford opposed- piston engine. Among them are such well-known companies as the North Eastern Marine Engineering Co. (1938), Ltd., the Wallsend Slipway & Engi- neering Co., Ltd., hlessrs. Swan, Hunter Ce R'igham Richardson, Lttl., and Messrs. It. Sr W. Hawthorn, Leslie & Co., Ltd.; while, overseas, the \Viiion- Fijenoord organization are now in a position to offer machinery of ~ h c L>oxford type, in addition to engines of other designs with which their name has long been associated. The Canadian-Vickers arrangement reprcscnts anothcr over- seas license. ' In view of the technical and practical success of the Doxford engine--the company recently announced that no fener than 163 opposetl- piston marine oil engines of the Doxford type were under construction in their own works and those of their licensees-this extension of licensing arrange:iicmt not only represents sound policy for this country, but is a development nhic-li will be welcomed by many shipowners and superintendent engineers.

Reference to the building of marine oil engines under liceiise recalls thc lac1 that Mcssrs. 1Villiam Gray 8c Co., Ltd., W e s t liartlepool, last year acquircd .I

license enabling them to build marine Diesel engines of the Polar design. 'Lliis company have not hitherto built Diesel machinery, and their decision to talic up the manufacture of a popular engine, with long experience behind it, is oiic which has much to conimend it. Any endeavor to enter the market w i t h < i completely new marine oil-engine design a t the present juncture would prob- ablv represent questionable cohlnlercia~ policy, irrespective of the iiierit:i or special characteristics of the design; and, i n any case, to nianufac.ture under license is certainly a sound and practicable course, both economicall>. a n t i technically, for a newcomer today, however well known.

Messrs. (;ray are to build one type of Polar engine, ivith one size of c!.linder, corresponding to the latest and larger version of this well-known engine, ivhich has been developed in Stockholm during the last fcw years. K n o w n a s thc hlT type, it is rated to develop 400 B.H.1'. per cylinder a t 250 K.P.M-a verv u eful size for direct-drive iristallations of medium power, or for those i n which indircct propulsion (with rnultiple engines anti reduction gearing) are sidered appropriate. In this particular version of the Polar engine, the Diesel Company's latest fuel-injection arrangements, which make for A smooth-running and quiet engine, are incorporated. Scavenging air i s sup- plied by a conipact fan-type blower (of fairly high speed) i n place of the reciprocating pump formerly employed.

The latest Sulzer crosshead-type marine Diescl engine, embodying. as i t does, a number of improvements and refinements in design, makes i t particti- Iwly attractive for cargo-ship and intermediate-liner propulsion. Stnnt1;irtI- iwtion has been carefully considered in the development of the range. .]I- though engines of the type have been built in Switzerland by Messrs. Sulzcr Brothers in recent months, the first British-built example has only recently been completed by Messrs. Alexander Stephen & Sons, Ltd., Linthouse, Govan, Glasgow. An improved design of cylinder cover. better cooling arrangements around the combustion-chamber end of the liner, modified fTaniing, changes in crankshaft design, a new piston design and a different arrangement of crosshead and small-end bearing are some of the changes which make this engine even better than the Sulzer single-acting, two-stroke cycle unit, which has given such good service in many vessels built before the war. bIessrs. Sulzer Brothers favor a separate scavenging pump for each cylinder, the pumps being driven from the appropriate niain crosshcad. In the Stephen-built version, however, the normal, single, reciprocating pump at the end of the eagine has been retained in the machinery recently completed.

One of the most significant technical developments of the year was marked by the placing in service of the Anglo-Saxon oil-tank ship Auricrcia. To all intents and purposes a standard 12,000-ton deadweight vessel of this c o n -

ierinieiit in fuel technique, initiated to esaininc the practical pro pciaterl with the possible use of heavy so-called boiler oil as fuel for thc

siiain Iliexl-engine cylinders. Service experience has confirmed the practical succcss of the venture. The merit of the development, as we see it, is that such interesting results should have been achieved with what is, virtually, a. s tandard Hawthorn-U'erkspoor Diesel engine, with under-piston pressure charging. The esperiments which preceded the decision to use this heavy ty!x uf fuel oil in the Awicula were initiated about three years ago, when ;I single-cylinder engine, of the same cylinder dimensions and general design 3 ~ ; the inain engine of the Ai t r i cdu (and many other vessels of :he iinglo-Srlxon fleet), was set to work on comparittively heavy, low-grade fuel oil in the St. Peter's IVorks of 3Iessrs. R. & \V. Hawthorn, Leslie CY: Co., Ltd., Newcastle- on-Tyne.

'l'he financing of these investigations and the experimental prograni gerieraily wt'rc the responsibility of the Anglo-Saxon Petroleum Co., Ltd. Before an!. attempt was made to burn the heavier fuel, the engine was run continuousl>- for s ~ v e n clays on pool marine Il iexl fuel, so that a coniplete record of its pcrforniancc on ordinary Diesel fuel might be available to provide a basis of c~imparison for the pcrformance with heavier-grade fuel. l h e next step was to employ ii mixture of normal LXesel oil and heavier Admiralty-type fuel oil, :ind this was successfully accomplished with qnly minor incidental diffcultics. I-ltiniately, it was found possible to operate the engine on Admiralty fuel oil .ilonc after various small, but iniportant, adjustments had been mode to obtain a combustion efficiency equal to that achieved with Diesel oil.

?'he conipletion of these experiments encouraged those responsible to cc. w e n further, antl the nest step was to attempt to burn really heavy Venezuelan Imiler fuel oil, having a maximuni viscosity of 1500 seconds Redwood 1. i i t 100 dcgrces F. 'The first tests were made with n misture consisting of 10 per cent of this fuel and 90 per cent of marine Diesel oil, subsequent experiment.; Ii,iving been made with progressively increased proportions of the heavy fuel oil, which the experimenters dubbed Ortioil. Eventually, it was found possible to run the en 'neon Ordoil only, once it had been started and warmed through on Diesel fuef? hluch was learned from theseexperiments, but, naturally, they 11. ere not of sufficiently long duration to establish with any degree of certiiint). t h e amount of cylinder-liner and piston-ring wear encountered with the inferior fuel. Nevertheless, the owners, encouraged by the experiments o n the single- c!linder unit, decided to proceed with an installation for a large vessel, antl the trials and subsequent service performance of the Azcriczda (built and engined by Messrs. R. & W. Hawthorn, Leslie Er Co., Lttl.) have denio:istrated that it is eminently practicable for an en ine of this type arid size to operate j v i i h what is virtually a heavy grade of Kiel oil, hitherto considered siiitabk onlv for u s e in boilers.

'I'he modifications made to the Auricula's engine were simple and straight- forward. For example, the pressure at which the fuel is injected into thc cylinders is higher than in the standard engine in which a normal grade of I>iesel oil is employed; and, a t the outset, standard fuel lines and connections were used, although these have been niodified in the l i h t of service experience. :\ most important change concerns the arrangements for securing an enhanced standard of purification of the fuel oil, by means of two-sta e ceritrifueing. The first stage is dealt with by a standard Alfa-Lava1 puriler, whence the tiitid passes to a second machine, of broadly similar type, but which incorpo-

1' ates certain changes in the plate design of the bowl: this latter machine is known as clarifier. The purifier is large in relation to the normal-service t hrough-put, the easier rating of the centrifuge being a not miniportant factor in the attainment of the especially good results necessary for trouble-free riitining.

The succew achieved in the Auricda-independent examination has shown that her machinery is functioning very well on the heavier fuel-is of con- siderable importance, for i t holds promise of very considerable savings to the otviiers when, as is contemplated, a- substantial proportion of their flcet has

i n n convcrred LD opc.rcitc on Ordoii. ’ 7 h ~ ,ill-purposz dml\ $uci-oil CCP ump- ::on tor the Auricda has been slightly incrc‘uetl-from approiimately 17 tons ‘0 J. little over 1234 tons-including the m a l l arnoiinr of Diesel oil requiicd for starting arid paneuvering operations. Contrary $0 the indicationq O F earlier experience in the uw of heavier fuel, i t is not anticipated that liner and ring wear will be greater thcn that associated with n o r m 1 Diesel fuel. ?‘he experiinental work is being continued with a view to exploring the possihillty of employing even heavier fuel, and the hope is entor ta ind that reliable mmeuvering without the use of Diesel oil may ultimately be realized.

In regard to Diesel engines of the smaller categories, good progress has beep inade by the British Internal-combustion Engine Research Association, w h u report that the research program is gettin into its stride at their laborator) <tit Slough, where excellent facilities an? equipment are available to tiw increased staff.

in addition to experimental work on test engines, undertiken rtiti: tiic object of establishing mrrthods of improving performance and durability, investigations are in progrms in connection with bearing performance, noise, bending fatigue of crankshafts and torsional vibration. Use is being rnadc i n the l+boratory of the latest developments in electronic techniques, and i l l many instances novel apparatue has been devised.

I<cprewntatives of the Association have visited Germany to study recent tlevelopments in engine design and research, and members of the Associqtion have had the opportunity of examining, a t the laboratory, examples of foreign engines, some of which have been tested in or for the laboratory.

Al number of special panels have k n appointed by the Research Cornnuttec to survey developments in gas turbines, pressure-charging, and torzion,il vibrations, and to advise the Committee as to appropriate courses of action.

DIESEL-ELECTRIC DRIVE. ’The ingenious Bowes drive, to which we have referred in previous surva\.s,

has attracted considerable attention among rnarinc engineers, and, if the claim.; made for i t should be substantiated by service results, i t should represent rl~:

important contribution to marine en ineering progress. Not only does t h k electrical device provide for reversal of the propeller without the intermediary of engine-reversing gear or mechanical-reversing gearbox, but i t also const!- tutes an efficient s d-reducin device, and, moreover, x w e s as a clutch between engine an8epropeller. f n addition, electric power for auxiliary piir- poses may be taken from the Bowes unit, so that the number of Diesel- generating sets in the engine-room may be reduced. Again, should the drive give trouble, i t is comparative1 simple to couple the driving and driven units, which then constitute 3 solid d h e . This last point is of practical significance only with the non-reversing type of Bowes unit, ie., where the engine is of the strai htforward direct-reversing tym, such as that in the CuaM Ltberalor -the onfv vessel which has so far been fitted

This American-device offers, the empl9ymat of a single enghe of- comparadvel~ h rif& of the advantages of a slow-running propeller: rn , the Hamiltan-M.A.N. .;ix-cylinder engine is rated !to develop 2164 B.H.P, at 240 R.P.M., whlle the propeflw speed is 120 P P . M . I t kc l abed that the combined weight of the compact two-stroke cyyle, trunk-piston main engine and Bowea-drive unit is less than that of the a r r e s ?ding directly-coupled ea ine of approximately the same rated output a d g l u e d for service speecfof 120 RP.M,, Tee efficiency of th’e f l o w s drive, as assesrd?rom the trialdata of the fnotorshlp referred to, is 9’1 per cent, excluding excitst?on, or 94,7 pet Rnt with ekciat ion, The difference appears to b$ s m e w h a t k g e , but is apparently explained by the fact that , in this instance, over-excifation was applied continuously to provide the necqssary sQ$&ty of 9 . Presumably, improved reeulte would be obtained in a futyre i n s @ E E a n d i t b,!wped that, when other units are built, the importam reversing chwacteristlc of, the Bow= &vim, and its ability to provide apdlary current from the main engine, will be

th the Boweo drive.

>.-,pioitstl. <'I'!x Cuabfal Lz'fic.iir!o; i s proviiieci \:.iih i tvo Uicsci-gcner

The tinit should prove attractive in oil-tank ships equipped with rotarh- ryo-oik pumps .which require l a r k electric motors; for the employment oi e main engine and Uowes unit as a generating set for port duty would secm

i o offer a useful economy in first cost. Stand-by power would, naturally, have '0 be provided with such an arrangenient, and, it may be added, au exccp- iionally reliable main engine would be necessary, especially with a single-screw kiyout.

A n interesting Diesel-electric propelling installation of the year is that of the single-screw passen er motorship Saga (390 feet 0 inch B.P., by 5.5 fcct 0 inch moulded, by 32 feet 11 inches nioulded to shelter deck, and 6545 tons ::ross). built for Rederiaktiebolaget Svenska Lloyd, Gothenburg. by the famous Gotaverken conipan for the owners' London-Gothcnburg services. The installation consists oy'four Gotaverken Diesel engines, developing Iogct-hei. 6700 I.H.P. a t 270 R.P.M. Each engine has eight cylinders, thc cylinder diameter being 500 millimeters and the stroke 700 millimeters.

i h e power is transmitted to the propeller shaft by means of :\sea e1eciri.c slipcouplings and reduction gearing, and the Sago is the first large Swedisli passenger ship in which this system has been adopted. h i o n g the advantagcs riainied for it are ihe economy of headroom in the machinery space-resulting from the relatively sniall height required to accommodate the four quick- r-unning engines-and the possibility of effecting adjustments to one of thc sinits, while the remainder continue to provide sufficient power to propcl thv ship a t a speed only a little less than the normal service speed of 18% knot:;.

MISCELLANEOUS.

c2.c~l of 250 mu'.)

~..

~- :*or many years, there has been little major change in the design anti manu- ture of marine rcfriperating plant in this country. A number of iirms h a w ered for this highly specialized equipment, and there have been few impor I dcvelopinerits in design or practice, but the wider employment of tiic igerant known as Freon is one of the changes which should be ment.ione.d.

I t i s interesting to remark that steam-jet refrigeration, which iias beer; tieveloped both here and in the United States, has begun to find a n increasin sphere of application in this country. While steam-jet refrigerating plant i not by any means new or novel in this countt the Empress of Britairz a n i l t i l e Queen Mary were both equipped with sucK-&nt-its wider use for air- conditioning purposes in warships and recent passenger liners has to be rccorded. At the present time, a t least two important mercantile vessels now Iieing built afe to have equipment of this type; and as the refrigerating plant Ivill be installed between the boiters and the ship's sides, very little, i f an!., useful space will be sacrificed. Again, somewhat similar, if smaller, plant i $ being provided in a new oil-tank ship, where i t is to be installed on a stringer a t the after end of the engine-room.

If expediency dictates, the pumps associated with the equipment may be located elsewhere (c.g., in the engine-room, adjacent to other pumps concerned with the main machinery), while the so-called flash chambers a n d the con- denser may be located in any convenient position-on another deck or el%>- where in the ship. The main essentials of this equipment are the flash 01' vacuum chambers, a simplified form of steam-jet thermo-compressor (having no moving parts) which drives the vapor from the flash chamber, a condenser with air ejectors, pumps for circulating chilled water to the heat-receiving apparatus, and condensate punips for returnin the condensed steam to the feed sysrem. Details have been given in an infcmnative paper recently pre- sented by Mr. W. Sampson before the h s t i t u t e of Marine Engineers. .?'he . design ig one which is. undoubtedIy,attrac<in ,mosiderabIe attention, for i t is simple, quiet in operation, has no mecharucaf ets. ne$s no l u b r & t h anti can be automatic$Jy controlled; 'It seems iwell.a&pted m the requitementa of air-conditioning schemes on B%arucularly ipboard, and, bebg of,modecate weight, it is likely to receive increasing qr+iderat$n for. new passenger tonnage. .

'

220 NOTES.

the specific fuel consumption has increased appreciably. Therefore a single, direct-drive diesel will operate unfavorably for an appreciable proportion of the time. With multiple powe: plants, either geared or electric, a portion of the plant may beshu t down during low power periods allowing the remainder to deliver the requirements at a relatively high load factor.

Also with dectrical direct-current drive the maximum power may be sup- plied for eweral diffeRnt conditions ofloperation.

Direct-current electric drive, 4ike the geared drive, has the advantages that the equipment is smaller and li hter than the direct drive; can be serviced and installed more conveniehtly anjeconomically ; and can offer greater reliability, the vessel being able to continue operation even when one engine is forced out of commission.

The applications where these advantages are important are not s6 evtensive and the advantages themselves are counterbalanced. by serious disadvantages.

Direct-current diesel-el&c equipment Costs close to 50 per cent aboye the cost of direct or geared drives.

Thtre is a I d s of approximately 15 per cent in the elwtrical equipment, a major factor in comparing fuel costB. Electrical equipment is large in size and requires special techniques for operation, maintenance, and repair. Con- trols are extensive and complicated.

Direct-current generating units operate at moderate speeds (500-850 revo- lutions r minute), 90 that diesel-electric plants require more room than a geared Ip." mel plant.

There is increased noise, maximum firing pressures and wear. Direct-current dieselelectric propulsion equipment cannot be used for

shipboard auxiliary purposes, because i t operates on a variable voltage. NEW DEVELOPMENTS.

The aforementioned types constituw the present basic diesel marine d1ib.c. Direct-drive units are far and away the most popular. Engine manufacturer5 have learned to build praiseworthy reliability into their equipment, and, as a result, there are actually many makes Of diesels, of various horsepower rah@s, which can offer continuous, reliable, close-to-full-load operation for many days or weeks at a time without respite. With this dependability available, and with the excelledt fuel ec?onomy of direct-drive units, their con- tinued popularity is understandab!e. Howtm?r, new developments are bound to exert ressure from the stand int of less weight, less space, greater overall vessel rePL?hility, and, possibly, Eg initiaI cost.

ALTERNA~HG CURRENT. One promising new deveIopment is the use of alternating current rather

than direct current. I t is lighter, qheaper, can be run faster and is much more rugged and cheaper to maintain than direct-current equipment. Its efficiency, however, is not much better than direct-current and in maneuvera- bilit characteristics i t is complicated, slow, and in general, is not even a5 gooJaa the direct-reversible diesel. Also, it is idflexible from the standpoint of supplying maximum power fof various operating conditions, and i t cannot vary Its torque Conversion ptopetties at all. This means that i t acts identically as a fix& rado reduction gear and, where hull resistance changes, the machin- ery canriat change to suit.

Alternatin current equipment, however, can be useful in multi le gencr- ating sets for%tge powers, rn cases where maneuverability and variagle torque conversioh is not important, and where the overall vessel requirements pre- clude mechanical coupling of the engines to the propeller. It also can offer large amounts of power in port, 9th the necessity of s ial or over-sited auxiliary unitd for that purpose albri However, since E m a i n propulsion equipment'is operating on variablt f uency its electrical power is not suitable for auxilia burposes at sea, excep2or limited pkrfods and particular appli- cations; bu 'u one or two of the m;tin generatid units could be operated on constaqt frequency as auxiliary units, thereb+ &ecting a uniformity of major power units on the vessel.

THE B O W E ~ DRIVE.

electridly just a !~ ahy alternaWr-synCRrtmotrn mbtor combination. Bemuse some of the power (dephding on thd pea^ Vaticr) W transmitted by renction, the efficiency is high and actually can &:high&' 5 per cent. Also, there is available a design for electrical fem+g.

The advantages claimed are: (1) a drscdnn ling, (2) speed reduc. tion from engine to pro ller shah, (3) d i torsional vibrations, (4) electt-icaI reversing, eleettical power the dock by braking the propeller shaft, and (6) elettricat power a t '& under certain conditions-

I t has, of course, the operitting disadvamg- of alternating current-no variable torque conversion, and slow &ectrical manewering operation. How- ever, as a single engine, moderatk M&, eleeulctil reducdon gear, i t is tar better than anything el* available. For this , and perhaps with the use of A. rectifyin uni t to obtain a u d b ~ auxi ta&, it will have applicntions and shoulckbe watched.

THE CONTWLUBLS P r m &OPELLER.

f iYDRAULrC D R T ~ One of the most prprnising p y e r tran,+igciion l e i ~ u m s of the future is

the h draulic q u i p m a t qf the rotary, F)um and-motor combination type. This Xydra.ulic mu,ipment can co~pete'.~lwg in efficiency, weight anq eiw with electrical equipment; has a good, if not b!etter, torque wnverdon dnd maneuvering properties; and has the acjd'tional, gttmcfiveness of being com- pletely m@anical. I n coat, t? i tshn4d be cornpetrtlve wi marine el&- trical equipment, particularly since its controls are very s i m p 2

AR DEV~LOP~EWTS IN Gk $SELS. war, the p m k of gm iR was breught under

control, succeesfuHy by impomtioms froor E m k t r i c m d hydraulic couplings. A la e number of shi have e n b u i K h e United Sbw with this equipment%iog thamar. %e Cpupl instaIled between the engine and the g a r o ~ ~ N $ E I ~ S S ygjppis&$$&$ from the reduction gear, athua albwmg 6mosth W i w e r o gclwer; e e ~ as a disconnecting coupl+g, &win justantamw disepgagement sh~uld ooa of the engittes become dtwbled; anf in the case of t m v b t s allows one of the

sittier electric 9~ h

eneires to run “Ahead” and the other “Aelarn,” R hich with coupling rnanipu- lation, gives excellent maneuveriog characteristics

CpUPhY add to C06f and decrease efficiency (2 to 3 pcr cent) but the) eliminate one ol the major prsbloms of geared equipment,

Experience shows that the g a r s themselves are reliable. lt might reson- ably be concluded that the geared dieeel.drive will enjoy an increase in popularity.

.

?IFTLICA?IONS TO VARIOUS TYPES OF SHIPS.

Tmuboa~s. The harbor tug requires low propeller s for maxiniurn thrust

maneuverability for speeding up the dockingoperation are definitely desirable. Theee requirements m y best filled b5 the direct-current electric drive, although the problem of cost and complication are difficult hurdles. Instal- lation of electrical drives on seagoing tugs, where rapid maneuverability is not often required, is not yuallyJusti+i.

Fcnies. In general, the irect rive, direct reversible d i e d has been most papular for ferryboat in+hions. I t is to be expected that tGis type en ine and the geared diesel wJl continue in popularity. However, for runs -,+&re ability to maneuver may h an appreciable factor in overall operating time, direct current d i d electric drive may be useful.

Cargo Vcsxls. Low fuel oonsuniption and high relbbility are the 111.lJOr requirements of the cargo vessel, Low-speed, direct-drive, or multiple, niediurn-speed, p e d diesels answer these requirements.

‘I‘he major auxiliary &ad lor cargo vessets occurs at the dock during winch operation. TberefMe, dieselslectric propulsion machinery, which can handle this auxiliary load a t the dock and thereby fi l l a dual purpose, has an attractive first-glance argument. The penalty, however, of electric propulsion losies a t w. as well as fitst cost, ik a distinct disadvantage.

Furthemlore, uith tendency for carrying refrigerated cargo and air-condi- tioning equipment, which can constitute an appreciable sea-load, there is additional r e a m for separate auxiliary power. Tankers. The direst drive or geared diesel d m s , for the same reasons as

for cargo vessels, moet hitable for tankers. However, like cargo vessels, tankers need appreciable p w e r a t the do& for Ioadin and unloading. Nevertheless, the penalty o electric?) propulsion losses antf i rs t cost is high.

Dredges, rn general., have an appreciable power load besides the main pumps. Cutting equi meet, jet p u m y and swinging machinery all re uire a p reciable amounts of &xi& power. here is good reason, therefore, ?or carekl stud! of a diesel-electric installatioq. Indeed, the flexibility required is so great that many installations have USXI several independent generators driven by a single engine.

When the dredge is self-propelfed. there is additiondl reawn for a diesel- electric installation. The power required by thc main punips and the p o N e r required for propulsion are both appreciable and, since peak pumping and propulsion loeds e u r alternately, and practically never simultaneously, one set of prime movers is sufficient for both functions, thereby saving appreciable $pace and wei ht.

Y?chts. Re$iable, li ht, and compact machinery is requiccd for yachting service. M e d i u m - s d direct-drive or probably geared diesels are particularly

a t low vessel bpeeds. Full torque conversion for a1 p““ types of tows aed rapid

ap licable for this service. fcc-Bruakus, Suwy Boa&, CousLGwrd CuUers and Salvage Kessds. Electric

drive’s torque conversion, maneuvering and 9. ratin ca bilities have par- ticular udulnpss in sueh vest&. The versati& of t i e c /kct turrent power d a n t in domirm the various assigned duties IS an expensive but genenllv Gsefulf&ture. - rMuinmenta for all kinds of tishin& vesds.

-

Fishing Tr&s’and Sehwrs. Reliability ahd simplicity are the dominating

SiW auxiliary load8 are periodk and moderate, the use of electric drive appears to have the impwtant advantages of being able to accomplish% dui! function. However, the necemty of simplicity and low first cost explains the

ritrcct drive's, contirruing p p u l a r i i ) . 1: 1.3 to ir . t . r y gcarcd units will enter the field.

i he torqueamversion quality ol electrial equipineiit IS ~ ~ d v , ~ r i u g e o u s r v h ! toRing nets, t h u s making electrial equipnter~f desirable for rnare rwson th.tu its ability to supply power to tk winches. I A c r d J stud) nia\ show :i sufliciently valuable to warrant an inttoductory instailztioii.

'Technical progress has made available engines which, while oper<itiriF .ii much higher speeds, have retained t h e dominant feature of reliability. 1'111- technical progress a n n o t be ignored. The higher speeds require either ( ! i t . uw of indirwt drives, or the accept?nce of a lawer propeller efficiency, a i Icast until further develo ments are made by the propeller designers ,

:\lthough the indirect $rive will h d mare and more mnsidyration i n 111,. future, i t is hoped that the low fuel consumption and extreme simplicitv or the dircut drive will be retained to as great a degree as p i b l e .

l o g i d corollary to low fuel consurn tisn IS the use of low-cost furl\ . Too much emphasis can hardly be p l a d o n the importance of t h i s sin& item on the overall cwt of power production in many ap ications. I n this connection, choid of engine speeds lor indirect drive shoul s' take into account the IIK' of low-cost fuels.

Finally, it is suggested that motorship operatm give consideration to thc . establishment of a cost analysis consumer organization similar to the Uiexl Engine hers' Association which has operated for many years to the grmt benefit of stationary plant operathrs and enghe builders. The return5 should he \\ell worth the relatively small expendktwe required. '

ATOMIC ENERGY AND ITS APPLICATIONS. Since the bursting of the atomic bambs over Nagasaki and Hiroshitnd

much has b w n written and published on atomic energy. This paper, written by a famous British physicist, Sir James Chadwlck, and reprinted from the December 1946 iasue of "Tbe Institut& of Fuel" is me Of the most coniplerc and understandable of the &ores of papers *hkh have appeared. I t gives a comparative! dimple descripthn of an atomic reattioh and then tells how it m a j 5 applt)ed. *the pro#uction 'ff pdwer. Finiiily, i t gives J realistic vicwpolnt of the limitations on atomic power and mme idea of its f u t u r e

l h e great techtmiogical developments and achievements of the past centurs or 50, which are the dominating features of e n t - d a y Gdization, constitu<e a n increasing control ovet the prowsees of%atum. These developments and th i s control have grown from an ever-widening knowiedge and understanding of natutal phenomwa. At no rime ha5 the #a&& advance of scientific knowl- edge and the fate with which thin imowledgg has been put'ihto practice amti exploited for technical developmenta been 60 rapM ;ls in recent years. 'I?+. i j espethlly the case in the physical sciences h which the mast remark;hIe advances have taken place during t h e r t So y v

st reah Insight into. the internal styur- r u n : of the atom. We have learned that each atom consmts of a cluster or cloud of n tively electrified corpuscles, the ekctrons, held t a t t r a c t i o n x m a positively charged nucleus, w ~ , a ~ o s 9 e 2 L 2 practically the whole mass of the atom, 1s extremely smell in siu: camped with the dimensions of the electron cloud.

The many problems connected with the conbgnratbn of the electron cluster have been etudied most successfully, and the results have led to a complete c la r ib t ion of tbe relationship between the 90 w so chemical elements $13 regards their ordinary physical and chemical propenies.

All the ordinary properties of matter, srich .ae strength and hardness elasticity, electrical conductivity, chemicat affinity, etc., on which all the processes involved in indwtrial and scientific develppments depend, are determined by the configuration of the electron cfustar and are prdctlcdlv independent of the structure of the atomic nucleus.

'These diecoveries have given us the