DP Mini Guide: Drive-Off — Uncommanded Thrust

Crew Connect DP Academy · Mini Guide 14

Drive-Off — Uncommanded Thrust

Topic: DP Emergencies · Sub-topic: Drive-Off  ·  Level: DPO / Senior DPO  ·  Read time: 8 min

1. What / Why / How

A drive-off means the vessel is being actively pushed off position by its own thrusters responding to a fault — bad reference data, a control system error, or a runaway thruster command — rather than passively drifting after losing power or control. The distinction matters: the appropriate immediate response can differ.

2. Recognition / Risk / But

Close to an installation, an actively driven vessel can move faster and less predictably than passive drift — the window to react before a genuine contact risk exists can be short. But: bad reference data is the most common cause, not the only one — a genuine control system fault, thruster command error, or operator input error are all possible too. The immediate priority is stopping the uncommanded movement, not definitively diagnosing the cause first.

3. Now / What next / Decision / Why

Once movement has stopped, assess actual current position relative to the hazard, confirm what genuinely caused the drive-off before considering any return to automatic control, and communicate the event and status.

4. Consequence / Reassess / Escalate

Manual control being stable only proves the fault isn't active under manual control — not that it's resolved or won't recur under automatic control. A cause traced to a specific reference input should directly inform how that system is treated going forward, not just a generic “everything's fine now.”

5. Recover / Verify / Human factor

Preparation for drive-off specifically means knowing, in advance, the fastest available way to interrupt uncommanded thrust on your vessel. Trap: treating stopped movement as proof of resolution rather than the first step.

Sources: IMO MSC.1/Circ.1580, IMCA M103 Rev.5.2, IMCA M166 Rev.3 (FMEA — drive-off failure modes). This guide is educational content, not a substitute for accredited DP training, vessel-specific FMEA/ASOG, or full-mission simulator assessment. Crew Connect never infers compliance with a specific vessel's applicable requirements — always verify against your own approved documents.