George Hunt was the second in command on board HMS Proteus, operating out of Alexandria. He describes how the first radar sets operated on submarines:
The only thing you had was a rectangular screen about 8 inches by 6 inches.
There was a row of green vertical uprightss across the bottom of the screen about an inch in height and looking like grass. When the radar detected an object, it got a return echo or pulse. This showed up on the screen as a ‘spike’ of ‘grass’ higher than its neighbours by, perhaps, another inch, depending upon the range and, therefore, the strength of the signal.
In those early days the aerial was only geared up to show the bearing of the ‘target’ relative to the ship’s head, so, of course, that had to be noted at the same time in order to obtain the true bearing. And that was about as far as we had got in a submarine with radar in those days.
However, on one occasion we did actually detect a small convoy of ships taking Germans to Crete, and the first detection that we had of this convoy was at night, was from the radar cabinet, so this was a plus for the radar. And because it was brand new and nobody knew very much about it we had two Dundee University students manning the radar set.
Anyway the radar on this occasion did produce this contact and sure enough there was a convoy. We couldn’t see it, of course, but we shadowed the convoy all night by radar and got ahead of it and dived in position so that it would go across the path of the rising sun and we would be at periscope depth.
They successfully torpedoed and sank the Tampico east of the Greek island of Andros on 3rd November 1941.
This memoir appears in Submarine: An Anthology of First-hand Accounts of the War Under the Sea, 1939-45. HMS Proteus is on Facebook.