[1] Despite warnings from locals that the bay was too exposed for these relatively fragile machines, in January 1917 a handful of Short Type 184 seaplanes were stationed at Porthmellon on St Mary's.

The first patrol was undertaken on 28 February 1917 and the first conclusive action took place on 27 May 1917, when an unidentified U-boat was spotted, on the surface, off Bryher.

The flying boat dropped two bombs and onshore observers witnessed the submarine's stern rising out of the water at an angle of 60° before she sank.

[1] By the summer, full facilities had been established and from August there were around 22 planes including Short Type 184 and Felixstowe F.5 flyingboats.

[3] A number of other significant actions followed, notably the thwarting of U-boat attacks on the White Star liner, Persic which sustained damage but managed to reach port On 18 August 1918, the unit became No.