Faslane Naval Base at Gare Loch west of Glasgow is home to Royal Navy's four Vanguard class Trident submarines — HMS Vanguard, HMS Victorious, HMS Vigilant and HMS Vengeance. Its shiplift is one of the largest in the world, and when confirmation of the safety case for its continued operation became necessary, our engineers provided an independent peer review and a technical assessment in support of the ultimately successful case.
Facilities for submarines at Faslane consist of the huge shiplift building and three jetties to the side of it. One of the Trident submarines is always on patrol while another is in maintenance. The remaining two are on standby. Their pressurised water reactor power plants are designed to operate for seven years without overhaul.
The shiplift can raise completely out of the water a 14,515 tonne (submerged weight), 150m by 13m wide Vanguard submarine in operational condition. The lift platform is built out over the loch on 821 tubular steel piles that are up to 50m long and driven into bedrock below the water, which is between 22 and 30m deep. Some of the piles are raked for extra lateral stability.
Our responsibilities included a structural assessment, recommendatons for modiifactions to the structure and contributions to the preparation of the safety case. In the course of this work, we undertook safety critical analysis, created a structural model of the shiplift, examined loading regimes and assessed the situation in relation to codes and from first principles.