Previous to the conflict
of World War One, the submarine was mainly seen as a tool of coastal
defence,and to aid fleets of naval ships, protecting their flanks.
Germany and Austria were to
prove that they were a supreme offensive weapon and the Allies
had to change operations and tactics to counteract this.
In the early 20th Century,
Submarines had been regular vistors to Cork,as part of visiting
fleets on manouveres, and for demonstrations, including the ill-fated
HMS A5. There were no submarines stationed here before 1917.
The unrestricted u-boat offensive
of 1917 was proving catastrophic to England and her Allies. Vice
-Admiral Lewis Bayley, received critical reports from the Admiralty
complaining that u-boats were rounding the north and West coasts
of Ireland with impunity.
This saw the advent of the
defence of the 'hunter-killer' submarine. patrolling Irish
waters, patrolling singly, shadowing commercial shippping,
in the hope of spotting an enemy submarine and attacking it.
Two flotillas were established
in Ireland. The Platypus and Vulcan flotillas, named
after the submarine depot ships HMS Platypus and HMS
Vulcan, which provided supplies, mobile workshops, and accomodation
to resting submariners.
During 1918 another depot ship HMS Ambrose was also stationed here to assist. This became
for a time a combined Vulcan/Ambrose Flotilla . Thse flotillas
were mobile, and at various stages were based in Queenstown (Cobh), Co.
Cork, Berehaven Co. Cork, Lough Swilly, Co.Donegal, and Killybegs
Twenty three Royal Navy
submarines were stationed in Ireland over the course of World
War One. By November 1918 There were five, all stationed in Donegal.