On the 24 August 2012 a Narrowboat was delivered by road to South Dock Marina in London for a new owner. The vessel was lifted into the dock and the new owner departed the lock with five adults but no lifejackets on board. The crew was warned about the dangers of this by the lock keeper but decided to continue and left the lock to make the transit across the river to the starboard side of the channel before turning upriver towards Limehouse Marina.

Port of London AuthorityBut the engine note then changed and when the crew opened the hatch to check, they discovered that the engine was half submerged. They tried to bail the water out but they were unable to cope and the engine room continued to fill before flooding the main cabin, submerging the aft coaming below the water, and sinking the boat within just ten seconds. The crew entered the water without lifejackets and were lucky to be rescued by a nearby Police Launch.

The review into the accident has shown that the hull of the vessel had been completely double-plated and the increased weight of this plating had resulted in a reduced safety clearance, with the bottom of the engine room vent just 65mm above the waterline. With three people on the aft deck, the bottom of the vent was submerged by 50mm, dooming the vessel to certain sinkage. As a result, the PLA has stated that the following safety lessons should be considered by all narrowboat owners before venturing onto the tidal Thames:

(1) The tidal Thames is a Category C waterway, with wave heights of up to 1.2 metres and vessels should be prepared to meet these conditions.

(2) Through-hull fittings, vents and exhaust outlets should be positioned as high up as practicable on narrowboats. Where they cannot be moved to a safe location, consideration should be given as to whether the vessel is suitable to navigate on the tidal Thames.

(3) Where modifications have been made to a vessel, such as the extensive use of double plating, it is important to check that sufficient safety clearance remains for the vessel to navigate on the intended waterway.

(4) Lifejackets and other safety equipment should always be provided on board vessels navigating on the tidal Thames and worn at all times when on deck.

(5) When buying a vessel, it is vital to have a pre-purchase survey undertaken by a competent surveyor who is aware of your intended use. For access to a properly qualified marine surveyor, visit www.ydsa.co.uk.