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SEWOL Ferry Capsizing and flooding Henk van den BOOM, Victor FERRARI, Rinnert van BASTEN BATENBURG
Seung Taek SEO [SIC] HIMT/RINA Sustainable and Safe Passenger Ships, Athens 2020
16 APRIL 2014; 08:48 - 09:40
3
16 April 2014; 476 people on board
4
172 people saved
5
Sewol
6
Approach
• Phase I: Turning & Heeling (< 45 deg)
Manoevring tests & Simulations • Computer simulations
• Model tests 1:25
• Navigation Simulator
• Phase II: Flooding & Sinking (> 45 degrees) • Model tests 1:30
• Computer simulations
7
Data made available
• Vessel geometrie
• Cargo mass & positions
• Tank volumes ?
• Centre of Gravity ??
• AIS position
• AIS heading (??)
• Heeling angle from dash cams in trucks
Transverse Stability
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• Ship geometry • Center of Gravity • Light weight ship
• Tanks (fuel, water, ballast)
• Free surfaces
• Cargo (cars, trucks & other)
• Passengers
Stability SEWOL
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• Arm of Stability GZ
0
0,05
0,1
0,15
0,2
0,25
0,3
0,35
0 20 40 60 80
Stab
ility
arm
[m
]
Heel angle [degrees]
GZ
GM
Phase I Turning & Heeling Tests
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Active systems:
1. Propulsion
2. Rudder autopilot
3. Stabilizing fins
4. Moving cargo
5. External Force
• Schaal 1:25 model
Moving Cargo modelling
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• Cargo lumped into 4 masses
• Transverse rail; linear motors
• Computer driven
• Settings: trigger angle, sliding acceleration, speed, excursion
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Turning test GM2C, speed 17.5 knots, rudder 25 degr. SB
Test program
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• Stability levels GM=0.01-0.65m • Rudder scenarios • Propeller scenarios • Sliding Cargo scenarios • Ship speed • Initial heel • Trim • External force (Winch)
Free sailing tests
Navigation Simulator
14
• 360 degrees outside view
• Manoevring Model
• Schip motions emulated in outside view
• Investigation “human factors”
• Steering scenarios
• Stability levels;GM=0.01-0.6m
Effect of stability & steering (model test results)
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• Effect of GM on heel • Effect of Rudder on heel
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Longitudinal location of mass / bow trim (model tests)
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Model test results compared with AIS track
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Phase II Flooding & Sinking
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Location Vent E-deck
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Captive Flooding tests
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Free Flooding tests
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Flooding tests & simulation compared with actual video
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Salvage March 2017
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Lifting (March 2018)
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Inspection May 2018
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External Force?
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Main Conclusions
• Stability of SEWOL was lacking (conversion, cargo, tanks, trim)
• Rudder excursion occured (helmsman, steering gear)
• Fast Turn with Large Heel (>18 degr.)
• Cargo (not properly secured), slided at 18 and 33 degr. heel
• The heeling increased to 45 degr.
• Water ingressed via scuppers and vent at C-deck
• Water flowed through vent pipe into stabilisation room and E.R.
• Due to water on C-deck, ferry capsized and flooded fast.
www.marin.nl