HMS Dolphin, Fort Blockhouse

AddressPO12 2AS, UK
Location typeNaval Base
Site Ownership and Access InformationFort Blockhouse is still in military use by the Royal Navy, and there is no public access. The adjacent site that was part of HMS Dolphin is today the Royal Navy Submarine Museum and can be visited by the public.
Contact detailsSee Royal Navy Submarine Museum website for opening times and admission charges.

Check details before visiting

Two “X-Craft” mini-submarines (numbered X-23 and X-24) left from HMS Dolphin for the Normandy coast five days ahead of D-Day. Each X-Craft carried five men from COPPs – Combined Operations Pilotage Parties – who waited under water in their small craft for several days, only surfacing for fresh air at night. Their wait was prolonged by a whole day because the Allied commanders decided to postpone the date of D-Day by 24 hours, due to the changing weather situation. As the Allied fleet approached in the early hours of D-Day, the two X-Craft surfaced and signalled out to sea as a final aid to navigation in the fleet’s final approach to the British and Canadian beaches.  

Motor Torpedo Boats (MTBs) that took part in D-Day were also based here and nearby at HMS Hornet. Being fast, small and highly manoeuvrable craft, the MTBs were at the front of the Allied fleet on D-Day, and also guarded the flanks of the landing area.

View on the D-Day On Your Doorstep map