Question 1

G1 has now recovered and come online. Full power is available. Four minutes have elapsed since the initial generator trip. The vessel is at 42m from the platform, drift has been arrested by manual thruster use, and position is now roughly stable under manual joystick control. The DPO is tempted to re-engage DP auto to recover the situation more quickly.

Should the DPO re-engage DP auto mode immediately?

Accepted Answer

Not yet. Before re-engaging DP auto, the DPO must verify the reference system status (have any GPS units drifted during the blackout?), confirm all three generators are stable, open the bus to restore DP2 redundancy, and run a rapid consequence analysis check — re-engaging DP auto with degraded or unverified reference inputs could drive the vessel further toward the platform if a reference has been corrupted during the blackout Re-engaging DP auto immediately after a blackout is one of the most dangerous points in blackout recovery — reference systems may have drifted or lost their fix during the power outage, and the DP system will act on whatever position it reads when it reconnects. If a DGNSS unit has lost its differential correction during the blackout and is now providing a degraded or incorrect position, re-engaging auto DP could command the vessel toward the platform. The correct sequence is: stabilise manually, verify all references are healthy and in agreement, confirm power is stable and bus is open, run consequence analysis, then re-engage auto DP.

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.