Experimental Anti U-Boat guns

[robinbird]

RAF Helensburgh conducted trials of anti-submarine warfare using flying boats. Just before the end of WW2 Sunderland PP109 was fitted with four fixed 0.303 calibre guns in the nose, loaded from the bomb aimer's position and under the control of the pilot for firing. The guns were harmonised to point at a target (submarine) when diving in attack. Did such guns see service?

 

[M. A. Rozon]

I am confused about the reported timing. The Sunderland Mark III, the definitive version of the aircraft, carried four (4) fixed nose-mounted .303 browning machineguns that were under the control of the pilot. This was a standard fitting that also carried over to the Sunderland Mk V. The nose turret remained as well. So I am looking for more context for your question.

 

[robinbird]

I only have a brief mention of this trial from a contemporary report. Maybe MAEE was fine tuning these guns, i.e. 'harmonising them' especially if this type of gun was already used operationally. Thank you for pointing this out. Maybe the serial number PP109 offers a clue? I will trace the history of this particualr Sunderland.

 

[JWilly]

Various British (and other nations') biplane flying boats of the 1920s and 30s were fitted with the Coventry Ordnance Works 37mm autocannon or other available guns in that weight and caliber range, for use against target vessels. The Vickers S 40mm autocannon evolved from the C.O.W. 37mm design.

THE CANNON PIONEERS

The Wikipedia article on the C.O.W. gun says that there was a plan to mount a forward-firing gun of this type to a Short Sunderland, presumably for antisubmarine fire since that was the primary task of the Sunderlands during WWII, but that plan never was implemented. Maybe the OP's source was alluding to that rearmament plan, rather than the quad .303s...?

 

[M. A. Rozon]

I edited my response. It was the Mark III and not the Mark II (finger trouble). I have corrected the error.

 

[TomS]

I edited my response. It was the Mark III and not the Mark II (finger trouble). I have corrected the error.

FWIW, I think PP109 was a Sunderland Mk V, which had the same fix forward-firing .303s as the Mk III. This mark was first delivered to operational units in February 1945, so very near the end of the war in Europe. That would explain the timing of the trials. Perhaps they were validating the harmonization techniques given the new engines and other tweaks in the Mark V version?

 

[robinbird]

ALL of MAEE's work at Helensburgh was experimental, secret and mostly about sinking U-Boats. Your reply TomS sounds right as to why it would be testing guns harmonised with the angle of dive Going through my files it appears this was the last wartime trial of a new Mk 5 PP109 which involved non stop firing of the nose turret guns, i.e. 21,785 rounds. Thanks everyone for helping me answer the question.