The Royal Navy SETT (Submarine Escape Training Tank) in Gosport is a 30m / 100′ deep tank, 5.5m in diameter with bottom and side hatches.
Constructed in 1953 the tank has recently been listed by the Local Authority (Grade II listing). The tank is filled with warm water, surface level is on the tenth floor of the tower and the main entry chamber just above ground level. The tank was built to train submariners how to escape from deep water and undertake confidence building exercises.
The tank has a capacity of approximately 153,000 gallons and a pressure of 3.5 bar when full.
Martin Ralph were instructed to undertake a condition survey of the steel SETT tank, including ultrasound testing of the steel integrity, inspecting the rubber seals to the escape hatches and assessing the filing surface coatings. This required Confined Space Working training and accreditation.
To carry out the inspection our surveyors operated from an inflatable dingy. The water in the tank was slowly released over a two day period, enabling them to descend while testing the surface area, exiting the tank after day one through one of the escape hatches, at 18m deep.