Laboratory Investigation of Polymer-flooding, ASP-flooding ...
Office of Marine Safety Stability and Flooding Eric Stolzenberg.
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Transcript of Office of Marine Safety Stability and Flooding Eric Stolzenberg.
Office of Marine Safety
Stability and FloodingStability and Flooding
Eric Stolzenberg
Presentation OverviewPresentation Overview
• Stability• Flooding progression• Impact of physical rudder loss• Effects of astern travel
Vessel ConfigurationVessel Configuration
OSV Ranger
Fishing Vessel Alaska Ranger
HoldRudderMachinery Spaces
Factory Deck
Fo’c’sle Deck
Wheelhouse
Ramp Freezers Processing Area
Trawl Deck
StabilityStability
• Stability criteria– Intact stability: capsizing– Damage stability: flooding
• Stability requirements– Necessary for vessel certification– Incorporate stability criteria
Vessel Intact StabilityVessel Intact Stability
• Owner monitored stability– Not required– Intact stability through T&S booklet– Damage stability not monitored or required
• Postaccident Coast Guard MSC review– Stability test confirmed– T&S booklet met requirements– Intact stability met requirements
Intact Stability MarginIntact Stability Margin
• Large stability margin prior to sinking• Downflooding points located aft
– Engineroom intake vents– Aft trim conditions at deeper drafts
quickly reduced the margin
Flooding ProgressionFlooding Progression
Flooding Progression — ProfileFlooding Progression — Profile
Aft Fish Bin(Freezer)
Flooding Progression — PlanFlooding Progression — Plan
Watertight Bulkhead
Watertight Bulkheads
Flooding Rate VerificationFlooding Rate Verification
• Coast Guard scenarios– Estimate 5 minutes to flood rudder room– Estimate 50 minutes for water to reach
switchboard
• Electrical switchboard– Will short if flooded– Vessel loses electrical power
• Loss of rudder flooding rate roughly corresponds to event timeline
RudderRudder
Upper Rudder Assembly
Lock Nut
Starboard Rudder
Hull
Thrust Bearing
Rudder Stock
Vessel Traveling AsternVessel Traveling Astern
• Exacerbated flooding– Increased rate– Decreased distance to downflooding
points– Increased pressure on hatches and
doors• Prevented crew from entering liferafts
Stability and Flooding SummaryStability and Flooding Summary• Vessel had adequate intact stability• Most likely encountered rudder loss• Would not have sunk if flooding contained
to rudder room• Sank from uncontrolled progressive
flooding• Astern travel accelerated flooding
Office of Marine Safety
Propulsion SystemPropulsion System
Eric Stolzenberg
Presentation OverviewPresentation Overview
• Causes of astern travel• Propulsion system overview• Propulsion system modification• Means to stop travel
CPP System OverviewCPP System Overview
Propulsion System LayoutPropulsion System Layout
Port main engine
Stbd main engine
Gear
GearPropulsion Shaft
Propulsion Shaft
Propeller
Propeller
Hydraulic pumps
Main Switchboard
Spindle Torque ForcesSpindle Torque Forces
Hydrodynamic Lift
Centrifugal Force
HubRotation
SpindleAxis
Net Spindle Torque
ASTERN
Rolls-Royce
CPP HubCPP Hub
Rolls-Royce
CPP System ModificationsCPP System Modifications
Main Switchboard
Stbd CPP Hydraulic Pumps
Port CPP Hydraulic Pumps
Stbd EnginePort Engine
Consequences of ModificationsConsequences of Modifications
Port PropellerStbd Propeller
Astern Travel SummaryAstern Travel Summary• Causes
– CPP pump modifications affected system redundancy
– Astern travel resulted from electrical power loss
– Engines were still turning propeller shafts• Stopping astern travel
– No means to control blade pitch– Crew could have secured engines to stop
shaft