Manoeuvring in Hazardous Area with No Echo Sounder Results in Grounding



At 0830 on 15 May 2016, Surprise’s skipper attended the SMBA’s daily planning meeting, where he was allocated a sightseeing trip to Western Rocks and Bishop Rock Lighthouse. Following the meeting, the skipper and his crewman moved Surprise from its mooring in St Mary’s Harbour to the quay, where 48 passengers embarked.

At about 1015, the skipper manoeuvred Surprise out of the harbour. To provide close-up views of seals and birds, Surprise passed close to several islands during the passage to Western Rocks. At about 1130, Surprise was manoeuvred at slow speed into the small bay between two large rocks, known as Dry Splat and Daisy. Once in the bay, the skipper stopped the vessel for a few minutes to allow the passengers time to enjoy the views and photograph the seals that were basking on the rocks nearby.

At about 1135, the skipper applied ahead power and started to manoeuvre Surprise out of the bay. As the vessel’s speed increased it struck a submerged rock. A loud scraping noise was heard as Surprise shuddered to a halt and lodged on the isolated rock. The rock penetrated Surprise’s hull below the waterline and the vessel started to take on water.

Realising that Surprise was aground and taking on water, the skipper disengaged the vessel’s propellers and manually started its electric bilge pumps. The skipper made a “Mayday” distress call on very high frequency (VHF) radio, channel 16, and instructed the crewman to help the passengers don their lifejackets. He then sought volunteers to manually operate the mechanical bilge pumps and ordered the crewman to release and infate the lifecraft.

The skipper’s “Mayday” was heard by Falmouth Coastguard and numerous local vessels that were operating nearby. The coastguard tasked a search and rescue helicopter and requested the launch of the St Mary’s Royal National Lifeboat Institution (RNLI) lifeboat. Three small local boats proceeded immediately to assist Surprise and the Isles of Scilly ambulance boat arrived soon after. By about 1150, all the passengers had been transferred from Surprise to the assisting boats. After the passengers had been evacuated, Surprise floated off the rock unaided.

Probable Cause

The investigation concluded that Surprise grounded because the skipper was unaware of an isolated, shallow rock when deliberately manoeuvring very close to exposed rocks so the passengers could observe basking seals. Insufficient passage planning had taken place prior to the trip and the skipper had not assessed where safe and unsafe areas existed.


  1. Surprise grounded on an isolated rock while being manoeuvred in a hazardous area during a wildlife sightseeing trip.
  2. The grounding occurred on an intertidal area of the chart where the skipper was wholly reliant on local knowledge to maintain navigational safety. Had conventional navigation techniques been applied when planning the trip, it would have been apparent that entering the bay was unsafe.
  3. The skipper relied upon an amount of wash around shallow rocks to aid him avoiding these hazards. The glassy calm conditions at the time of the accident meant that this indicator was not present.
  4. Had the SMBA skippers developed generic passage plans and set limits for UKC and proximity to hazards such as shallow rocks, this accident might have been avoided.
  5. More effective use of electronic navigation aids, including an echo sounder, could have improved the safety of navigation on board Surprise.
  6. Although Surprise’s onboard procedures did not include the risk of grounding, the emergency response of the crew was swift and appropriate, ensuring all the passengers were evacuated safely back to shore

Safety Issues

  • A passage plan had not been prepared for the trip. Passage planning is essential for every voyage to ensure all navigational hazards are identified and avoided.
  • Safety management systems should include guidance on the conduct of navigation and reactions to take in an emergency. Neither Surprise’s onboard procedures or the St Mary’s Boatmen’s Association safety plans contained sufficient guidance.
  • The Council of the Isles of Scilly’s procedures for issuing local boatman’s licences lacked rigour; there was no syllabus for candidates to follow, or assurance of training standards


  • The Council of the Isles of Scilly has been recommended to review its procedures for the examination of candidates for local boatman’s licences.
  • The St Mary’s Boatmen’s Association has been recommended to update its safety management system to incorporate guidance on passage planning.

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Source: MAIB


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