Question 1

Three minutes into the blackout, the emergency generator is now online and two thrusters are back online on emergency power. The vessel has drifted to approximately 55m from the platform. The drift rate is approximately 0.4 knots toward the platform. Two thrusters are available.

With two thrusters online and 55m to the platform, what is the immediate priority?

Accepted Answer

Use the two available thrusters to arrest the drift and if possible create separation distance from the platform — any thrust that reduces the closing speed buys time for full power recovery. This is not DP2 — it is manual survival manoeuvreing with whatever is available Two thrusters may not maintain position but they can reduce the closing rate. At 0.4 knots closing with 55m of sea room, the vessel has approximately 4 minutes at current rate — enough time that reducing the closing rate from 0.4 to 0.1 knots could double the available time for generator recovery. Every second of reduced closing speed is valuable. "Hold and wait" is passive when the vessel is actively drifting into a platform. Announcing collision without attempting to use available thrust is defeatist. Anchoring in 55m close to a platform in an emergency with limited power is high-risk — thruster arrest of drift is the priority.

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.