PLA Safety Bulletin for Narrowboat Users on the Tidal Thames

Issue date: 3rd October 2012

The Port of London Authority issued a safety bulletin in response to the sinking of a narrow boat in Limehouse Reach.

On the 24th August a narrow boat 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 requested to lock out of the
marina as they had an overnight berth in Limehouse Marina; a short distance up the River Thames.  The vessel departed the lock at 17:00 with 5 adults and 1 dog aboard. The vessel transited directly across the river to the starboard side of the channel and then turned upriver towards Limehouse Marina.

Shortly into their transit the crew noted a change in the engine note and opened the engine room hatch to find the engine half submerged. All persons quickly moved to the stern to try and bail out the engine room, but were unable to cope with the ingress of water into the vessel. The engine room continued to fill with water and flooded into the main cabin, submerging the aft coaming below the water, resulting in severe flooding of the vessel which sank within 10 seconds. All of the crew and the dog entered the water without lifejackets, but were rescued by a nearby RIB and Police Launch.

Safety Lessons: 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 being positioned approximately 65mm above the waterline. With 3 persons positioned on the aft deck the bottom of the engine room air vent became submerged beneath the waterline by 50mm, the resulting downflooding and sinking of the vessel was inevitable.

The following safety lessons should be carefully considered by narrowboat owners before venturing onto the tidal Thames.

  1. The tidal Thames is considered to be a Category C waterway, where wave heights of up to 1.2m may be encountered and vessels should be suitably prepared to meet these conditions.
  2. Through hull fittings, vents and exhaust outlets should be positioned as high up as practicable on narrowboats to meet the conditions likely to be encountered. Where through hull fittings, vents and exhaust outlets 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 safely navigate in the intended waterway.
  4. Lifejackets and other safety equipment should always be provided on board vessels navigating on the tidal Thames and it is strongly recommended that Lifejackets are worn at all times when on deck.
  5. When purchasing a vessel it is essential to have a pre-purchase survey undertaken by a competent surveyor ensuring the surveyor is aware of your intended use of the vessel