Question 1

The gas platform OIM calls the bridge and orders the vessel to move to a standoff of 500m as a precaution following the blackout. The master believes the vessel is now stable under manual joystick with two verified references. The vessel is at 42m from the platform.

Does the OIM have the authority to direct the vessel's manoeuvring, and how should the master respond?

Accepted Answer

The OIM has authority as the installation authority to direct vessels operating in the field to move to safe distances for installation safety reasons. The master should comply with the instruction to increase standoff, as the OIM's assessment of installation risk following a vessel blackout event is a legitimate safety decision — while retaining command of how the vessel moves to achieve the standoff The OIM (Offshore Installation Manager) has authority under the Offshore Installations and Pipeline Works Regulations (and equivalent in other jurisdictions) to direct vessel movements within the 500m safety zone of the installation for installation safety purposes. The master's command authority is over how the vessel moves — not a veto on the OIM's legitimate safety instruction to stand off. In this case, the OIM's call for a 500m standoff after a DP2 vessel blackout event 42m from a gas platform is entirely proportionate. The master should acknowledge, confirm he is recovering DP capability, and begin the controlled withdrawal to 500m.

Question 2

EMERGENCY SCENARIO — DP2 PLATFORM SUPPLY VESSEL

Vessel: Offshore PSV, DP2 class. Location: 80m from a fixed gas platform, holding position to deliver equipment. DPO on watch. Three DGNSS references active, two gyros operational (Gyro 3 offline for calibration). Sea state: 1.8m, wind 22 knots SW. Thruster configuration: full complement, open bus, consequence analysis test passed 90 minutes ago.

Work through the following 10 decision points in sequence — each builds on the last.

--- POINT 1 OF 10 ---

Without warning, the main generator (G1) trips offline. The DP system sounds an alarm. The bus is still open. The remaining generators (G2, G3) are online and picking up load. Position is currently stable.

What is the DPO's first action?

Accepted Answer

Immediately check the power status panel to confirm which generators are online, verify the bus is still open, and assess whether the remaining power configuration still meets DP2 WCF requirements in the current conditions The DPO's immediate response to any system alarm is active assessment — not passive waiting. Waiting for auto-restart risks losing 30 seconds of situational awareness during which the power situation may worsen. Closing the bus tie immediately is the most dangerous response — it connects both power sections and creates a common cause failure risk. Waiting for the engine room assessment before taking DP action passes decision authority to a team who cannot see the DP system status. The DPO must immediately understand what power is available and whether DP2 capability is maintained with the current thruster configuration and reduced generation.

Question 3

20 seconds after G1 tripped, G2 begins overloading as it attempts to absorb G1's load. G2's frequency is dropping. The power management system (PMS) is attempting to auto-shed non-essential loads. The DPO has confirmed that DP2 WCF may not be maintained if G2 also trips.

What is the DPO's priority action at this point?

Accepted Answer

Inform the master immediately, declare a DP Alert, begin controlled manual thruster reduction on the most loaded thrusters to reduce electrical demand and help stabilise G2, while simultaneously monitoring position At this point the scenario is escalating — the DPO cannot wait for automated systems to resolve it. The master must be informed immediately (this is now a DP Alert situation). Controlled manual reduction of thruster demand on the highest-loaded thrusters removes electrical load while preserving position-keeping capability better than an across-the-board minimum power command (which removes all fine control). Closing the bus in a G2 overload situation is the worst possible action — a fault propagating from G2 would then take out all power simultaneously. The PMS may not shed enough load fast enough; DPO manual intervention is appropriate.