Operation & Vessel Maneuvering Flashcards
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Read the first 7 Operation & Vessel Maneuvering flashcards as text
When executing a DP approach to a fixed platform in current-dominated conditions, the operator should align the vessel so that:
Answer: The vessel's most powerful thrusters face the dominant force
Orienting the vessel so its most powerful thrusters oppose the dominant environmental force maximizes station-keeping capacity and control authority.
During a DP operation, the operator notices the vessel's actual heading deviating consistently from the DP-commanded heading. The FIRST action should be to:
Answer: Check gyrocompass inputs and verify sensor validity
A persistent heading deviation often indicates a sensor input problem; verifying gyrocompass validity before taking control action prevents compounding the issue.
What is the primary purpose of performing a 'consequence analysis' on a DP vessel before operations?
Answer: To determine which thruster failures would cause the vessel to lose position
Consequence analysis simulates thruster failure scenarios to determine which single or combined failures would cause loss of position, informing the required DP class.
A DP vessel is operating in 'DP2' mode. Which statement about redundancy is correct?
Answer: Any single failure must not result in loss of position or heading
IMO DP Class 2 (DP2) requires that any single failure of active components or systems must not cause loss of position or heading.
During a vessel approach, the DP operator uses the 'joystick mode' rather than fully automatic DP. This mode differs from auto-DP because:
Answer: The operator provides manual force commands while the DP system allocates thrust
In joystick mode the operator commands forces and moments directly, but the DP system still handles thrust allocation among individual thrusters.
What effect does a strong tidal current have on DP vessel operations near a fixed structure?
Answer: It can create suction and bank effects, complicating position keeping
Strong tidal currents near fixed structures can generate hydrodynamic interaction forces such as suction and bank effects that the DP system must compensate.
When a DP vessel is operating in 'auto-heading' but not in 'auto-position', the operator must:
Answer: Manually control surge and sway while the DP maintains heading automatically
In auto-heading only mode, the DP system manages heading via thruster allocation while the operator manually controls the vessel's position in surge and sway.