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Key contribution of Oceanographic research in providing an economic solution to Zeebrugge’s lack of hinterland connectivity. Paul Moeyaert. Wave measurement. Solutions:. Noorderkanaal Dockships “extended” estuair regime. Access to the network of inland waterways from Zeebrugge:. - PowerPoint PPT Presentation
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Lloyd’s Register EMEA
Key contribution of Oceanographic research in providing an economic solution to Zeebrugge’s lack of hinterland connectivity
Paul Moeyaert
Lloyd’s Register EMEA
Wave measurement
Lloyd’s Register EMEA
Solutions:
• Noorderkanaal
• Dockships
• “extended” estuair regime
Lloyd’s Register EMEA
Access to the network of inland waterways from Zeebrugge:• Traditional inlandwater tankers
Provided “good’ weather
• CoastersBut too high requirementsAnd high investment/operational
costs
Due to lack of reliable knowledge of the risk-level
Lloyd’s Register EMEA
Lloyd’s Register EMEA
Extended Estuair
• Based on Risk analyses
• Simulation of ships motions and behaviour as a response to the 10years wave spectra: in the particular sea area
Lloyd’s Register EMEA
Statistical distribution of occurances of dangerous situations
• Slamming
• Greenseas
• Rolling
• Bending moment
Lloyd’s Register EMEA
Acceptable frequency
• Bending moment : once a life time
• Slamming: once per year
• Green seas : once per life time
Lloyd’s Register EMEA
Iterative process of designIf the number of incidents proves to be too
high : 2 possible actions:
•Restrict the allowable weather conditions
And/or
•Increase strength
Optimum solution
Lloyd’s Register EMEA
Relative vertical motion of point : fore, keel exceeding draft fore: number of exceedings per trajectory as a function of significant wave height in measured directional wave spectra Bol van Heist, Western Scheldt – Zeebrugge
1.0E-06
1.0E-05
1.0E-04
1.0E-03
1.0E-02
1.0E-01
1.0E+00
1.0E+01
1.0E+020 0.5 1 1.5 2 2.5 3
significant wave height (m)
num
ber o
f exc
eeda
nces
per
traj
ecto
ry (-
)
conditional minimumconditional maximumconditional averagecumulative average
SCHELDT-ZEEBRUGGE-SCHELDT
CARCARRIER - DRAFT 2.5 mMOTION POINTS 7-9 - SLAMMING
REF LEVEL KEEL
DIRECTIONAL SPECTRA BOL VAN HEIST 1998
Lloyd’s Register EMEA
Significant Wave Height
• Is a far more accurate criterion for reflecting the risks compared to the old yardstick : Beaufort Number
• As basis for designing ships
• But also as a criterium for the captain: whether to make the voyage or the wait for better circumstances
Lloyd’s Register EMEA
Further possible improvements
• Accuracy of predictions on medium term
• Directional predictions
• Distinction between:Swell
– Caused by remote storms – Long waves, traveling at known speed– well predictable
Local waves– Same predictability like the local wind– Shortcrested waves
Lloyd’s Register EMEA
0
0.2
0.4
0.6
0.8
1
1.2
1.4
0 0.5 1 1.5 2 2.5 3wave frequency (rad/s)
side
ver
tical
am
plitu
de d
ue to
roll
/ wav
e am
plitu
de
(m/m
)
0 10 20
30 40 50
60 70 80
90 100 110
120 130 140
150 160 170
180
angle of incidence (deg)CARCARRIERDRAFT 2.50 m