decided to shadow the convoy from a distance believing this would provide them with greater opportunities to engage shadowing U-boats. Two Swordfish were kept at immediate readiness to take off and engage any submarine sightings. On 23 April, one of the patrolling Swordfish sighted a U-boat on the surface but it had dived before they got into an attacking position. That same afternoon, another U-boat was sighted by the convoy; they signalled Biter, which was away. By the time the lone Swordfish dispatched had arrived, the U-boat () had been sunk by . Biter kept up her anti-submarine patrols over the next days and on 25 April, the radar operator on Biter reported a submarine contact. The destroyer dispatched to investigate could not find anything, then at 16:25 a Swordfish sighted a U-boat on the surface only from Biter. Dropping two depth charges the Swordfish reported the sighting and another Swordfish and were sent to assist. Pathfinder followed up the Swordfish attack with depth charges of her own, and at 18:40 surfaced and was abandoned by her crew. The convoy safely reached Argentia on 19 April without any loss but had sunk two U-boats. Convoy HX 237 Biter and her destroyers left Argentia on 5 May to join the home bound convoy HX 237, which was escorted by 2nd Canadian Escort Group. At first Abel Smith refused to place his support group in the convoy but was subsequently ordered to do so by the Admiralty. Fog prevented any flying until 07:30 on 7 May, when two Swordfish took off and located the convoy and provided an anti-submarine patrol. The carrier and escorts arrived an hour later. Two Martlets which until now had been idle took part in a patrol but lost the convoy and had to ditch beside a straggling merchant ship which rescued the crews. Ordered to close with the convoy by the Commander-in Chief (C-in-C) Western Approaches bad weather prevented any flying until after 16:00 on 10 May. The Swordfish responded to a sighting of a U-boat on the surface dropping two depth charges but was hit by anti-aircraft fire from the submarine. A second Swordfish had taken off to assist but could not find the U-boat or the convoy in the bad weather and was forced to ditch beside a straggling merchant ship. On 11 May, a Swordfish engaged another U-boat on the surface which initially fought