Question 1

The vessel is now at 500m standoff. All three generators are online, bus is open, all four thrusters are operational, all three DGNSS units are in agreement, and the master has full DP2 capability restored. The project manager calls and asks when the vessel can return to 80m to resume cargo operations.

What must happen before the vessel returns to the 80m working position?

Accepted Answer

Before returning to the working position, the vessel must: run a full consequence analysis test at the current standoff position, confirm ASOG criteria are met with the current configuration, brief the DPO team on the incident and any changes in system status, confirm the platform OIM is satisfied and agrees to the vessel returning, and log the blackout incident formally in the DP and official logbooks Restoring system capability does not automatically mean operations should immediately resume. Following a DP2 blackout incident near a live gas platform, there are mandatory steps before returning to a risk position: the consequence analysis test verifies the restored configuration actually meets DP2 margin requirements; the ASOG review confirms all criteria are met; the DPO briefing ensures the whole team understands what happened and what to watch for; the platform OIM's agreement confirms the installation authority is satisfied; and the incident must be formally logged. Returning to 80m before completing these steps risks repeating the incident without having understood what caused the blackout in the first place.

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.