By the end of 1940 shipping losses in the 'Battle of the
Atlantic' were mounting. Metropolitan Vickers Ltd were contracted
to produce some 1.25 m sets (Type 281) and some more precise
units (Type 282). They were in effect, marine versions of
the CHL system.
On the 26th May 1941 the pocket battleship Bismarck was finally
tracked by Coastal Command (using ASV) and HMS Sheffield and
was sunk with torpedoes from HMS Dorsetshire 24 hours later.