DETERMINATION OF SHIP SQUAT AND UKCUSING GPS-OTF

Brian Morse, Stéphanie Michaud and Rock Santerre Project ENV #14

GEOIDE Annual ConferenceToronto

May 22-24 2002

NETWORK OF CENTRES OF EXCELLENCE IN GEOMATICS - PROJECT ENV#14

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Objectives of the Project ENV #14

• Improve GPS-OTF algorithms

• Integrate of GLONASS and GPS phase observations

• Ionospheric modeling

• Precise GPS point positioning

• Study squat and under-keel clearance (UKC)of merchant ships using GPS

NETWORK OF CENTRES OF EXCELLENCE IN GEOMATICS - PROJECT ENV#14

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Context of Maritime Transportation

• Maritime transportation is big business

• Industries’ competitiveness :Carrying extra cargo to expand the profit margin

Maximizing route efficiency to optimize travel time

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Why does the Seaway need a safe UKC ?

A safe UKC is required to ensure :

• Adequate manoeuvrability• Sufficient stopping distance• Sufficient space for sedimentation• Adequate accounting of errors in bathymetry• Economical fuel consumption• Protection of the ship’s hull• Protection of the waterway• Protection of the environment• Adequate accounting of vessel pitch, roll and squat

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Squat and Under-Keel Clearance (UKC)

WATER LEVELWATER LEVEL

SQUAT

CHANNEL’S LIMITS

MARGE DE MANOEUVRE

« OVER DREDGING »UNDER-KEEL CLEARANCE

SHIP’SDRAFT

TIDE

ZÉRO DES CARTES

NOMINAL DEPTH

NETWORK OF CENTRES OF EXCELLENCE IN GEOMATICS - PROJECT ENV#14

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St. Lawrence Seaway study sites

St. Catherine lock

St. Lambert lock

Beauharnois lock

Montréal

St. Lambert lock to Beauharnois lock : 45 km

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4 GPS antennas on board ships

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Bow

Mid-Ship

PortStarboard

33 transits monitoredOctober - November 2000

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-0.20

0.00

0.20

0.40

0.60

0.80

30000 30200 30400 30600 30800 31000Channel station (m)

Squ

at (m

) ; P

itch

(m)

Squat Pitch

Travel direction

Pitch

Squat

Squat during ships meetings7

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Qualitative analysis to assess the repeatability of squat

• Prediction of squat with 3 models:

– Simard:

– Tuck:

– Barrass 2:

• Take into account the ship’s speed and the cross-section area ratio

• Model both elements differently for each equation

LFhS 2nhmax =

)SK2nhF1

2nhF

3ppL

sin(ppL5.0SK2nhF1

2nhF

2ppLbS

−

∇+−

∇= 1.46

30VSCS

08.2k

3/22b

max =

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Equation proposed to the Seaway

Canal de la Rive Sud

NETWORK OF CENTRES OF EXCELLENCE IN GEOMATICS - PROJECT ENV#14

Equation proposed to the Seaway10

Lake St. Louis

NETWORK OF CENTRES OF EXCELLENCE IN GEOMATICS - PROJECT ENV#14

Conclusions on the repeatability of squat11

NETWORK OF CENTRES OF EXCELLENCE IN GEOMATICS - PROJECT ENV#14

• Squat behaviour is “qualitatively similar but statistically different”

• Ships of different types have a similar squat behaviour, with possible exception of Trad. Lakers

• There is some systematic and unexplained behaviour going on, e.g.:change in water surface elevation, surges, sharp changes in rudder and propeller ship manœuvres, variable channel morphology, ship pitch, roll and heave, ship meetings

Acknowledgements12

GEOIDE NetworkSt. Lawrence Seaway Management CorporationFleet Technology LimitedWaterway Simulation Technology Inc.Géolocation Inc.Canada Transport Development Centre

For more information on the Project ENV#14:www.scg.ulaval.ca /gps-rs/ Research-GEOIDE

NETWORK OF CENTRES OF EXCELLENCE IN GEOMATICS - PROJECT ENV#14