DPO Site Management 2 — Questions and Answers
Question 1: When approaching a fixed installation in DP mode, what is the standard protocol before entering the 500-meter exclusion zone?
- Obtain permission from the installation's Offshore Installation Manager (OIM) (Correct answer)
- Notify the coastguard and reduce speed to bare steerageway
- Switch to manual override and post an extra lookout
- Complete a pre-arrival engine test and log the time
Correct answer: Obtain permission from the installation's Offshore Installation Manager (OIM)
IMCA and industry standards require the DP vessel master to obtain explicit permission from the OIM before entering the 500-meter safety zone around any fixed installation.
Question 2: A site-specific risk assessment for DP operations must be reviewed and updated when:
- The vessel changes watch teams at shift handover
- There is a significant change in environmental conditions, scope of work, or vessel status (Correct answer)
- The DP operator logs a new entry in the FMEA
- The charterer requests a daily progress report
Correct answer: There is a significant change in environmental conditions, scope of work, or vessel status
Risk assessments are living documents that must be updated whenever the operational environment, workscope, or equipment status changes materially.
Question 3: During site management, what is the primary purpose of defining a 'worst-case failure' mode before operations begin?
- To satisfy flag state reporting requirements
- To determine the vessel's capability envelope and whether DP can safely hold position if that failure occurs (Correct answer)
- To calculate insurance premiums for the charter party
- To log the failure in the planned maintenance system
Correct answer: To determine the vessel's capability envelope and whether DP can safely hold position if that failure occurs
Identifying the worst-case failure (WCF) lets the crew verify that DP has sufficient redundancy to maintain position after that failure without endangering personnel or assets.
Question 4: A guard vessel assigned to a DP construction site is primarily responsible for:
- Maintaining the DP reference sensor network for the working vessel
- Controlling vessel traffic and warning approaching ships away from the exclusion zone (Correct answer)
- Providing redundant propulsion backup if the main vessel loses power
- Conducting subsea surveys of the work area on a daily basis
Correct answer: Controlling vessel traffic and warning approaching ships away from the exclusion zone
The guard vessel's primary role is traffic control — intercepting and redirecting vessels that may encroach on the safety zone around the operation.
Question 5: Before commencing DP operations near a subsea pipeline, the DP operator should first:
- Confirm the pipeline's burial depth exceeds 3 meters along the entire route
- Obtain accurate as-built charts or survey data showing the pipeline's exact position and any free-spans (Correct answer)
- Request that the pipeline operator temporarily depressurize the line
- Switch the vessel heading to align the bow with the pipeline direction
Correct answer: Obtain accurate as-built charts or survey data showing the pipeline's exact position and any free-spans
Knowing the precise location, routing, and condition (especially free-spans) of subsea pipelines is essential to avoid inadvertent contact with thrusters or dropped objects.
Question 6: When the DP Capability Plot shows the vessel can hold position in winds up to 35 knots from any direction, but the site ASOG limits operations to 25 knots, the operator should:
- Operate up to 35 knots since the DP system is capable of handling it
- Adhere to the 25-knot ASOG limit because site-specific risk factors may not be reflected in the generic capability plot (Correct answer)
- Request a variance from the OIM and continue if approved
- Average the two values and use 30 knots as the working limit
Correct answer: Adhere to the 25-knot ASOG limit because site-specific risk factors may not be reflected in the generic capability plot
The ASOG (Activity Specific Operating Guidelines) incorporates site hazards, equipment criticality, and consequence of position loss that a generic capability plot cannot capture.
Question 7: During a DP diving operation, the diver reports that one thruster in the exclusion zone is rotating slowly. The correct immediate action is:
- Inform the dive supervisor immediately and inhibit or shut down that thruster pending diver recovery (Correct answer)
- Increase the power to other thrusters to compensate and continue the dive
- Reduce DP gains to minimize thruster demand and log the event
- Switch to joystick control to manually override the thruster behavior
Correct answer: Inform the dive supervisor immediately and inhibit or shut down that thruster pending diver recovery
Diver safety is paramount — a rotating thruster in the exclusion zone poses immediate lethal risk, so the dive supervisor must be informed and the thruster inhibited immediately.
DPO Site Management 2
When approaching a fixed installation in DP mode, what is the standard protocol before entering the 500-meter exclusion zone?