Tuesday, 12 March 2019

Norman Gandy 2


By 12 March 1943 Convoy OS44 had advanced into the Bay of Biscay having enjoyed a week of, apparently, trouble free sailing. The eleven-fronted convoy advanced with Silverbeech in the front rank, 8th from the port in the line of advance and with the Marwarri to the port and the Empire Glade to the starboard.

In a formation of aircraft, pilots maintain a constant station on the adjacent aircraft by visual sight lines.  For example, to maintain echelon on the leader, distance out could be maintained by maintaining a constant sight line using a reference on the wing tip (the navigation light) and the nose of the leader,  forward and back by (say) looking along the hinge line of the leader’s elevator and up and down simply by being able to see an equal proportion of the upper and lower surface of the wing simultaneously.  Line abreast, at sea, without radar or other distance measuring equipment would have presented considerable challenges.  I understand that distance was maintained by taking sightings of the adjacent ship’s mast and using the known elevation of the mast above the surface and the angle subtended, calculated the distance with simple trigonometry.  Presumably, matters became more difficult in reduced visibility?

The prospect of trouble ahead was revealed when the convoy signalled the Admiralty, “Emergency, aircraft shadowing.”  Later, HMS Rochester, one of the escorting sloops, signalled that a Focke-Wulf aircraft, probably a Condor, was shadowing the convoy at very low height.  Contemporary German intelligence reports identify “a convoy consisting of 47 ships and 6 escort vessels on a course of 1800, medium speed, in BE 9284.” BE9248 is a square on the German map in the Bay of Biscay.  Quite apart from the difficulty of concealing departure from Liverpool it appears that the Germans were reading at least some of the Admiralty codes and were pre-warned of the approach of OS44.  Later the same day, whilst aerial shadowing continued, at least 3 U-Boats were waiting in Square BE9284.  Some bombs were dropped from unidentified aircraft but none hit the target.  It is not clear which side dropped the bombs but, in the confusion, a friendly Flying Fortress was engaged by one of the escorts. Indeed, the situation appeared to have escalated such that the Convoy was ordered to alter course.

No comments:

Post a Comment