Channel Transits from Shipyard to open sea of Astute Class submarines

BAE SYSTEMS Submarines in Barrow-in-Furness (UK) is building a new series of submarines, the Astute Class (length 100 m). The shipyard is connected to open sea via a 15 km long channel. After construction, the submarines need to pass this channel to get to open sea, where they are handed over to the Ministry of Defence. The channel only allows exit manoeuvres of the submarines around High Water and under limited wave conditions. The channel was originally designed by Deltares | Delft Hydraulics around 1991 for the previous class of submarines, the Vanguard Class (length 150 m). The present study was aimed at verifying whether the existing channel design is suitable for the exit manoeuvres of the new class of submarines. Detailed field measurements, scale model testing, flow and wave calculations, and calculations of the vessel motions in waves have resulted in a state-of-theart hydrodynamic and nautical study. The study showed that the existing channel is suitable for the new class of submarines. Furthermore, weather windows have been computed that are used on the day of a planned exit manoeuvre to evaluate the feasibility based on forecasted wave conditions offshore, ensuring safe exit transits of the Astute Class submarines. The first of the Astute Class submarines successfully made the exit transit on 15 November 2009.