All Sectors

Thirty Minutes on Radar and No Action: The Apache/Serinah Collision and What Every Officer Must Know About COLREGS Rule 18

🕑 5 min read words Safety • Incident

Firth of Clyde, 25 April 2024 — 14:31

Apache, a 274-metre crude oil tanker loaded with 129,000 tonnes of light crude, was making its approach to the Clydeport pilot boarding area at 9.2 knots. On the bridge: the master, the second officer (OOW), and a helmsman. The master and 2/O were completing the pre-arrival checklist.

On the radar, 4.4 nautical miles fine on the port bow, was Serinah — a 9.9m stern trawler making circular clockwise tows around a seabed depression in the Firth of Clyde, trawling at 2.7 knots. Apache’s bridge team could see it visually. The 2/O was monitoring its position.

They were aware of Serinah for the next 30 minutes. They took no avoiding action.

At 15:03:30, Apache’s bow anchor struck Serinah. The tanker ran over Serinah’s trawl wires, pulling the stern under. Serinah sank rapidly. All three of Serinah’s crew entered the water. Two deckhands boarded the liferaft. The skipper was pushed away by the wash from Apache’s propeller and remained in 9.6°C water, one arm through an incompletely donned PFD, for approximately 15 minutes.

Apache continued towards the pilot station.

What the Investigation Found

On Apache: The Give-Way Vessel That Expected the Other to Move

Apache was unambiguously the give-way vessel. COLREGS Rule 18(a)(iii): a power-driven vessel shall keep out of the way of a vessel engaged in fishing. Rule 16: the give-way vessel shall take early and substantial action to keep well clear. Apache’s company SMS required a 1nm CPA minimum in coastal waters. The master’s standing orders instructed the OOW to call the master if CPA would drop below 1nm.

None of it produced action. Apache’s CPA alarm was set to trigger at 0.3nm — well inside the company minimum. By the time it sounded, the two vessels were approximately 100 metres apart.

The MAIB found two reasons for the inaction. First, Apache’s master was ‘used to fishing vessels getting very close to their vessel then turning away at the last moment’ — and the bridge team applied this prior experience as a substitute for COLREGS assessment. Rule 7(c) is explicit: ‘Assumptions shall not be made on the basis of scanty information.’ Second, when the master joined the bridge, his presence ‘likely inhibited the 2/O from taking positive action.’ A shared authority gap formed: the 2/O deferred to the master; the master assumed the 2/O would act. Both waited.

On Serinah: The Stand-On Vessel Without the Knowledge to Act

Serinah’s skipper was resting below. Deckhand 1 was on watch. Neither deckhand had completed any formal navigational training. Their knowledge of COLREGS came from a single remark at a safety course: that all other vessels have to keep out of the way while a fishing boat is engaged in fishing.

That is a partial truth. It reflects Rule 18. It omits Rule 17(b) — the obligation to take action when the give-way vessel is clearly not doing so. Without knowing Rule 17, Deckhand 1 had no framework for understanding why, with a 274m tanker closing at 9.2 knots and not altering course, he needed to call the skipper now — not in a few more minutes.

At 15:00, with the vessels 0.8nm apart, Deckhand 1 put the helm hard to starboard. Serinah’s towed gear restricted the rate of turn. The deckhand did not consider stopping the vessel or releasing the trawl to increase manoeuvrability. The skipper was called when collision was seconds away.

After the Collision: Apache Continued Passage

Apache’s master contacted Clydeport LPS using incorrect procedures (‘port state control’, ‘lifeboat control’ — not HMCG) and then continued towards the pilot station. He believed the crew were in the liferaft. He did not know the skipper was still in the water.

At 15:21 — 18 minutes after the collision — HMCG Belfast reminded the master of his duty under UNCLOS Article 98 and the Merchant Shipping Act 1995 Section 92 to render assistance. By that point Apache was almost 2nm away from the liferaft. The RNLI Lamlash ILB reached the liferaft at 15:47. Serinah’s three crew were uninjured.

What If?

What if Apache had acted at the company's own 1nm CPA minimum? At 1nm, ample sea room and ample time. A 5–10 degree course alteration would have provided a safe passing distance. The rule, the SMS, and the standing orders all required it before that point.

What if Deckhand 1 had called the skipper when the tanker was 3nm away? A skipper with 20 minutes available can release the trawl, stop the vessel, alter course, or use VHF. A skipper called with seconds remaining has none of those options.

What if Apache had stopped after the collision? UNCLOS Article 98 and MSA 1995 Section 92 are unconditional. The master did not need to know the skipper was in the water — the obligation is to stay until there is no further need. Schedule does not override it.

For OOWs on Tankers and Cargo Vessels

COLREGS Rule 7: a contact on a steady bearing at closing range is not a doubtful situation — it is a risk of collision. Your company CPA minimum is the latest point for action. If your master is on the bridge and the situation is developing, his presence should accelerate the decision, not create a shared deferral. If you believe action is required, take it — or explicitly hand the decision to the master by saying so.

For Masters

Prior experience of other vessels acting a certain way is not a defence under COLREGS Rule 7(c). When you join the bridge in a developing situation, your first question is not “is there a risk?” — it is “what action is required now, and how much room is left?” After a collision: stop. The duty to render assistance under UNCLOS Article 98 and MSA 1995 Section 92 is unconditional.

For Fishing Vessel Skippers

Who holds the watch when you are below? What do they know about COLREGS Rule 17? Do they know to call you early? MAIB Recommendation 2026/112 calls for mandatory navigational training for watchkeepers on fishing vessels 7m–16.5m. Until that is law, it falls to the skipper and operator to ensure anyone holding a watch has the knowledge and the standing instruction to call you before the situation is unmanageable.

Vessel Checklist

CPA monitoring: At what point is a converging contact formally assessed? At what point is action taken? Is that point before your company CPA minimum?
Fishing vessel watchkeeper training: Do your deckhands know COLREGS Rules 7, 17, and 18? Do they know Rule 17(b) requires action when the give-way vessel fails? When are they trained to call you?
Post-collision procedure: Does your bridge team know the duty to render assistance under UNCLOS and the MSA? Do they know the correct distress procedure for persons in the water?

Test Your Knowledge

Try a quick navigation round at Crew Connect — COLREGS questions for tanker OOW, Master, and fishing vessel crew from this investigation.