In the Battle of the Atlantic the business of escorting convoys of ships was an increasing strain on the Royal Navy. Until more destroyers could be built they were reliant on large numbers of ‘corvettes’ for the role.
Over 300 of these small warships were built, mostly in the Flower Class - they were all named after flowers. They were adapted from a design for a commercial whaler and could be produced quickly and cheaply in most small shipyards. They were the true workhorses of the anti-submarine convoy escort duty, around half of the ships performing this role were from the Flower Class. Apart from their depth charges they were lightly armed.
HMS Picotee was escorting convoy ONS.4 from Greenock (Scotland) to Iceland. On the night of 11th/12th August 1941 she went to investigate the report of a U-boat. She was never seen again.
The PICOTEE took station on the starboard bow of the convoy, with the anti-submarine trawler AYRSHIRE on the port side. At 2200/11th the PICOTEE relayed by light signal to the AYRSHIRE an intercepted wireless report of an unidentified submarine in the vicinity of the convoy. The AYRSHIRE had already received a similar report on a different wave length but the position given differed by one degree of longitude and the PICOTEE's attention was drawn to the discrepancy. However, it was estimated that the submarine would be about 30 miles eastward of the convoy and the PICOTEE, informing the AYRSHIRE that she intended to sweep astern of the convoy, proceeded accordingly. This was the last signal received from the PICOTEE. The AYRSHIRE commenced to sweep ahead of the convoy, considering it desirable to remain with the convoy unless otherwise ordered by the PICOTEE.
At about 0150/12th in approximate position 62° North, 18° West, the PICOTEE was observed to steam up the port side of the convoy at full speed, cross ahead of the AYRSHIRE and disappear into the darkness down the starboard side. About five minutes later a pattern of six depth charges was heard exploding, the PICOTEE by this time being out of sight from the AYRSHIRE (visibility was about one mile). Nothing unusual was observed despite a keen lookout; the PICOTEE was not seen again and, assuming that she had been called away to rejoin the 4th escort group, the AYRSHIRE went on with the convoy to Iceland.
When the PICOTEE failed to return to base enquiries as to her whereabouts were started at once. She failed to answer signals requesting her to report her position and it was found that she had not been seen by aircraft flying from Iceland. She had to be presumed lost with all hands when a careful air search of the area failed to find her or any trace of survivors.
A subsequent inquiry found that two officers of one of the merchant ships in the convoy had seen a large cloud of smoke and heard the sound of escaping steam from the direction of the PICOTEE. When the smoke cleared they saw the bows of a corvette rising out of the water at about 45°. They had seen no flash, heard no loud explosion - only "dull thuds". They were convinced that the corvette had not been torpedoed and that the explosion had occurred on board the ship itself. But opinion on the cause of the disaster was divided and the problem had to remain unresolved for some years.
Not until long after the end of the war, when captured U-boat logs were examined, was it established that the PICOTEE had been torpedoed by the German submarine U568. Entries in her log showed that her Captain had sighted a Corvette (which he could not identify) near convoy ONS.4 soon after the PICOTEE had last been seen by the AYRSHIRE. He fired torpedoes, one of which hit the corvette amidships just below the bridge. She broke in two and sank almost immediately, some of her depth charges exploding as she sank in approximate position 62° I5' North, 17° 59' West, about 70 miles south of Iceland.
There were no survivors: the entire ship's company of 5 officers and 61 ratings was reported missing presumed killed.1