The RAF established a Flying Boat base at Pembroke Dock in 1930 after the Royal Navy closed the Ship Building facilities in 1926, which had produced many famous warships & 5 Royal Yachts during it's time. At first just a few Aircraft were stationed there but as war was approaching it gradually became one of the most important Coastal Command bases of the conflict. Being situated at the South Western tip of Wales it was ideal for the coverage of the Western Approaches by Long Range Patrol Aircraft such as the Short Sunderland & Consolidated PBY Catalina both of which saw service at "PD" as it became known to Airmen who were stationed there. The first Aircraft to be based at PD were of an older generation - The Short Singapore and Supermarine Southampton & Stranraer Bi-Plane Flying Boats. But once the war started in earnest the Empire Flying Boats of BOAC were commandeered by the RAF for use as Patrol Aircraft until more suitable replacements could be built. Short Brothers immediately came up with a militarised version of it's S.23 Empire Flying Boat which was designated S.25 and this was to become the famous Sunderland. Built in Belfast, Rochester and the Lake District this famous aircraft would become a deadly adversary of the U-Boats operating in the Western Approaches & the Bay of Biscay. Some of the early types to operate from PD - Short Singapore, Supermarine Southampton & Supermarine Stranraer. The Short Sunderland Mk V & Mk III.