Prediction and Mitigation of Passing Ship
Interaction Effects
Scott W. Fenical, PE, D.CE, D.PE
Coast & Harbor Engineering, Inc.
October 8, 2015
(415) 773-2164 [email protected]
DREDGING YOUR DOCKS2015 Seminar
Presentation Outline
• Coast & Harbor Engineering
• Overview of passing ship interaction effects
• Analysis methodology
• Model overview and validations
• Modeling advances
• Mitigation measures
• Conclusions
• Coastal, marine and dredging engineers
• Expertise in coastal processes, coastal and dredging design, and maritime
• Coast & Harbor offices in Corpus Christi, Austin, New Orleans, San Francisco, Seattle, Delray Beach
• 2014 – A Division of Hatch Mott MacDonald
Coast & Harbor Engineering
Passing Ship Interaction Effects
April 10, 1912 at Southamptonhttp://www.lostliners.com/content/flagships/Titanic/maiden.html
Passing Ship Analysis Methodology
1. Ship hydrodynamic modeling
2. Hydrodynamic fields, load calculations
3. Impact analysis
a. Dynamic mooring analysis
• Mooring lines, bollards, fenders
• Motions, downtime
b. Squat, maneuvering
c. Effects of channel deepening, channel bank
erosion, habitat impacts
Hydrodynamic Model Overview
• Hydrodynamic model generated from CHE’s coastal processes
modeling system
• Incorporates ambient currents, waves, winds, tides
• Expanded to include multiple moving/berthed vessel hull models,
complex maneuvering.
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-150
0
150
300
0 100 200 300 400 500 600
Time (seconds)
Longitudin
al Load (
metr
ic t
ons) Remery Average
VH-LU Model
Measured Data
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1000
0 100 200 300 400 500 600
Time (seconds)
Late
ral Load (
metr
ic t
ons)
Remery Average
VH-LU Model
Measured Data
-40,000
-20,000
0
20,000
40,000
0 100 200 300 400 500 600
Time (seconds)
Mo
men
t (m
etr
ic t
on-m
ete
rs)
Remery Average
VH-LU Model
Measured Data
Validation - Passing Vessel ForcesMARIN (1974)
SURGE SWAY
YAW
Validation - Passing Vessel ForcesMARIN (2010)
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0.1
800 850 900 950 1000 1050 1100 1150 1200 1250 1300 1350
Time (sec)
Wa
ter
Su
rfa
ce
Ele
va
tio
n (
m)
Measured
VH-LU Model
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0
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600
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Time (sec)
Surg
e F
orc
e (
kN
)
Measured Surge
VH-LU Surge
Measured Sway
VH-LU Sway
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5,000
10,000
15,000
850 950 1050 1150 1250
Time (sec)
Yaw
Mom
ent
(kN
-m)
Measured Yaw
VH-LU Yaw
Quay
Quay
• Field hydrodynamics• Port of Oakland 1999: containerships in canal-type channel
• MRGO 2005: bulk carrier in trench-type channel
• Corpus Christi Ship Channel 2004: tankers in trench-type channel
• Port Canaveral 2013: cruise ships in canal-type channel
• Laboratory hydrodynamics• Flanders 2009: containerships with submerged bank
• MARIN 2010: containerships with quay
• Laboratory loads• MARIN 1974: tankers in open water
• MARIN 2010: containerships with vertical bulkhead
Model Validation Summary
Modeling Advances
• Maneuvering in Complex Channels
– Changing speed
– Changing drift angle
– Most channels aren’t straight
• Ambient Hydrodynamics
– Steady currents
– Variable current fields near terminals
• Hydrodynamic Phenomena - Surprises
– Bow waves
– Broken bore effects
– Bathtub effects
Route Specification for Complex Channels
• Channels are very complex, and need to avoid using any false
bathymetry for accurate hydrodynamics
• Typically defined with assistance from channel design drawings or
other similar information
• Some channels have “kinks”, can be difficult to prescribe route with
changes in speed and drift angle
• Simulator developed for quick and efficient route development for
passing ship studies
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Disney Magic
WSE
[ft]
Date & Time [UTC]
Bathtub Effects
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Norweigan Gem
WSE
[ft]
Date & Time [UTC]
Bathtub Effects
Overview of Modeling System Applications
• System has been successfully applied at over 90 different
berths world-wide
• System applied to wide range of vessels including tankers,
barges/barge packs, LNG carriers, cruise ships, destroyers,
submarines, tugs, pontoons
• Many successful recent applications in Texas
• Houston (Port, private)
• Galveston (private)
• Corpus Christi (Port, private)
• Port Arthur (Port, private)
• Beaumont (Private)
Mitigation Measures
• Majority of on-channel projects begin design with preferred
concept, mooring system evolves following initial results
• In confined channel, typically lack of surge restraint is biggest
problem
• Mitigation measures evaluated include:
o More lines in spring service, if possible/safe
o Berth modifications to reduce forces on berthed ships (setback, over-
dredging, end shapes)
o Waterway modifications to facilitate lower-speed transit
o Mooring system enhancements
o Draft limitations at berth
o Mitigation measure effectiveness is very site specific
Conclusions
• Numerical modeling provides accurate passing ship forces
• Efficient and realistic evaluation of vessel hydrodynamic problems
• In confined channels, passing ship forces are a major factor
affecting design of mooring system and berth
• Vessel hydrodynamic evaluations are now becoming a routine
and typical part of terminal development and mooring system
design/upgrade
Prediction and Mitigation of Passing Ship
Interaction Effects
Scott W. Fenical, PE, D.CE, D.PE
Coast & Harbor Engineering, Inc.
October 8, 2015
(415) 773-2164 [email protected]
DREDGING YOUR DOCKS2015 Seminar