Scottish prawn trawler Sustain hit rocks near Ullapool after its skipper fell asleep; he was exhausted after days at sea and no watch alarm was fitted

On the evening of 16 November 2023, the prawn trawler Sustain ran aground on rocks at the entrance to Loch Broom, north-west Scotland, while returning to Ullapool. The vessel had left port in the early hours of that morning to begin day 4 of its fishing run. According to the Marine Accident Investigation Branch report, the skipper, who was alone in the wheelhouse, had fallen asleep, and no watch alarm was fitted on board. The grounding happened at 1946. All the crew were unharmed, but Sustain was later declared a constructive total loss and dismantled by specialist divers in early 2024.What happened to the prawn trawler Sustain near UllapoolThe crew of Sustain landed their catch at Ullapool at about 1900 on 15 November 2023 and then cooked dinner. The skipper stayed on board to repair a deck wash pump, while the two deckhands went home to rest before the next day's work. At about 0200 on 16 November, having taken longer than anticipated, the skipper completed the repair and recalled the deckhands. The report states that Sustain was underway about 30 minutes later, heading for the fishing grounds west of the Summer Isles to begin the fourth day of a planned eight- to nine-day fishing run.The skipper went below to sleep at 0300 after handing the watch to the two deckhands. At 0710 the deckhands woke the skipper to take the watch so they could prepare to shoot the net for the first tow of the day. The skipper remained on watch from 0730, when the tow began, until about midday, when the crew hauled the net and shot it away again at 1230. After a light lunch, the skipper took the afternoon watch. The second tow was hauled at 1730, and at about 1800 the skipper set a course back towards Ullapool.Why did the prawn trawler Sustain run aground near Loch BroomSustain passed through the Summer Isles and the Carn Skerries, which mark the entrance to Loch Broom. At about 1930, as the vessel steamed past Annat Bay, the skipper felt tired, opened the wheelhouse windows, had a cup of coffee and sat in the wheelhouse chair. The skipper fell asleep sometime later. At 1946, Sustain grounded on rocks at Rubha Camas a' Mhaoraich while making 7.7 knots. The skipper awoke and took the engine out of gear, and the deckhands, who had been working below, came up to see what had happened.Conditions at the time were light winds from the south-south-west with a weak tidal stream setting east into Loch Broom. The report states that the skipper set courses on the plotter but navigated by eye except in unfamiliar areas. Sustain's autopilot followed magnetic compass courses set by the user and did not interface with the plotter. According to the report, plotter data showed that the course set after Eilean Dubh would have passed about 2 cables north-east of Rubha Camas a' Mhaoraich, and that after the Carn Skerries the course over ground drifted 3° to starboard. The MAIB analysis states that, had the set course been maintained, Sustain would have passed only 1 cable clear of dangerously shallow water.Why did Sustain have no watch alarm on boardSustain's wheelhouse had a plotter that fulfilled basic navigation functions but did not meet the Mini Electronic Chart Display and Information System (Mini-ECDIS) standard and had no navigational warning or alarm functionality. The report adds that there was no watch alarm fitted, and that the engine exhaust ran through the wheelhouse, making it warm in all weather conditions. According to the MAIB, the vessel's safety risk assessment, last reviewed on 21 June 2023, identified the risk of ineffective watchkeeping leading to grounding. Its control measures were calling another crew member if tired and ensuring a watch alarm was fitted and working correctly. The report states that these control measures were not implemented.The report records that Marine Guidance Note 313 (F) recommended a watch alarm on all vessels where only one person might be keeping a navigational watch. A footnote in the report explains that watch alarms detect inactivity in the wheelhouse and sound an audible alert both locally and at other locations on the vessel. The MAIB also cites MGN 137 (M+F), which strongly advised against the watchkeeper acting as sole lookout at night. According to the report, a previous accident, the grounding of the fishing vessel Golden Promise on Stroma on 7 September 2011, involved a skipper who fell asleep, and the watch alarm was probably not functioning at the time. The MAIB states that the two deckhands were sorting the catch when Sustain grounded.Why did the Sustain skipper fall asleep before the groundingThe skipper had been awake from about 0600 to 0300 on the day before the accident, a period of over 21 hours, and had slept for approximately 4 hours immediately before taking the morning, afternoon and evening watches. The report states that the skipper had accumulated 7.8 hours of sleep debt over the four days of the fishing run, in addition to 10.25 hours carried over from the previous run, giving a chronic sleep debt of 18 hours. It adds that the 2-day rest period between runs was shorter than the usual 4 days. The skipper fell asleep because of fatigue from working overnight to repair the pump and a build-up of sleep debt, and that the warm, comfortable and dark wheelhouse increased the risk.The crew could not move Sustain using the engine, the power block or the trawl doors, and an attempt to establish a tow with the Royal National Lifeboat Institution (RNLI) was unsuccessful. The crew were taken to Ullapool in an RNLI all-weather lifeboat early on 17 November. By 18 November the hull had breached, and on 21 November the remaining fuel and salvageable gear were removed. The wind increased the following week, peaking at over 40kts, and the vessel was declared a constructive total loss at the end of November. Specialist divers dismantled it in early 2024.You use AI every day. Now get your AI Quotient. Take the AIQ test.