S E C R E T.
	Office of Commodore (D),
	Western Approaches.
	6 College Avenue,
	Londonderry.
	No.DW.40.310.OP.
	THE COMMANDER IN CHIEF,
	WESTERN APPROACHES,
	REMARKS BY COMMODORE (D), WESTERN APPROACHES.
	CONVOY O.N.S. 5.
	Submitted.  The attached Report of Proceedings from H.M.S. DUNCAN, Commander P.W. Gretton, D.S.O., O.B.E., D.S.C., R.N., Senior Officer B.7 Group, covers the outward passage of O.N.S.5 from 22nd April, 1943 to 9th May, 1943.
	2.  Although eleven merchant vessels were lost from this Convoy, the final showing can still be considered a major victory.  Reports from E.G.3 have not yet been received, but from reports already at hand, it will be seen that forty-five attacks were carried out on U-Boats in the vicinity of the Convoy.  It is difficult to assess the results of these with any degree of accuracy, but there appears to be four certainties, SUNFLOWER, SNOWFLAKE, VIDETTE and LOOSESTRIFE, getting one each.  340 odd Depth Charges were fired by ships of B.7 and 1st Escort Group with only two failures.  This in itself is a fine achievement, and shows a very high standard of Depth Charge efficiency in these Groups, and is definitely the result of stiff training.
	3.  A point which is brought out is that when a close R.D.F. ring of well-trained Escorts is round the Convoy they can defeat the U-Boat on practically every occasion, as was proved by the action on the night of 28th/29th April, when six attacks were beaten off without loss.  It is noticed that losses to the Convoy did not occur until the close screen had been reduced to five and then to four Escorts.  It is considered that it is essential for the safety of a Convoy that there should be eight Escorts stationed on the close screen.  On the night of 4th/5th May, five merchant vessels were torpedoed after the close screen had been reduced to five Escorts, and it is considered that if OFFA and ORIBI, who were on the extended screen, had been brought in to support the close screen, as was done the following night, better protection for the Convoy would certainly have resulted.  The foregoing remarks infer no restriction on how the inner screen should be disposed, and without question it should be "packed" on the expected direction of attack if this is clearly indicated.  In this instance, OFFA and ORIBI, disposed singly on the outer screen, could not contribute much to the safety of the convoy and were themselves in considerable danger of being torpedoed.
	4.  It is noticed on two occasions TAY, whose asdics were out of action, was stationed in the ahead screen.  With the present-day tactics of U-Boats of carrying out submerged attacks, it is considered imperative that the asdics of all vessels on the ahead screen should be in full operation.  A better position for TAY under these conditions would have been on the quarter or astern.
	5.  The Escorts of the successful night of 4th/5th May when possibly five U-Boats were destroyed and numerous others damaged and no merchant vessels lost, were greatly assisted by the poor visibility which existed throughout most of the night, as all the evidence shows that the U-Boats were taken unawares, and attacked before they could take drastic avoiding action.  This seems to indicate that all U-Boats are not fitted with R.D.F., and presumably still have to rely on their hydrophone to receive warning of the approach of Escorts.
	6.  On no less than five occasions when U-Boats were being chased or attacked by Escorts they retaliated by firing torpedoes.  It is considered that Escorts should be warned that when in contact with U-Boats at fairly close range they should always point towards, so as to present the smallest possible target.
	7./ . . . . . . . .

 

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	7.  As was certain to happen with such a large number of attacks, a few mistakes were made, such as Hedgehog not always being used when it should have been, and the depth setting selected not always being of the best.  The errors have been pointed out to the vessels concerned.
	8.  Remarks on Communication matters are contained in Appendix I to this letter.
	9.  Report of Proceedings of 1st Support Group, Senior Officer in H.M.S. PELICAN, is attached as an Enclosure, and remarks thereon are included in the main report.
	10.  H/F D/F Reports have been forwarded direct to Director of Naval Intelligence.
	COMMODORE (D).
	Enclosures.
	1.  Report of Proceedings of B.7 Escort Group.
	2.  Report of Proceedings of 1st Support Group.
	(a)  Covering letter from Commanding Officer, H.M.S. PELICAN.
	(b)  Forms S.1203 and Narrative of attacks made by PELICAN, SPEY, SENNEN and JED
	(c)  Relevant signals.
	(d)  H/F D/F Report.
	(e)  Letters from H.M.S. SPEY and H.M.S. SENNEN regarding Hydrophone Effects from Icebergs.
	(f)  Track Charts.
	(g)  SENNEN's Report on Failure of Armament.

 

	APPENDIX I.
	COMMUNICATIONS - Convoy O.N.S.5.
	1.  There is definite evidence of a bad area for H/F communicating between about 27 and 40 west and north of 56 north.  DUNCAN had difficulty in transmitting to shore, and German control stations faded out.  The fault was not with DUNCAN, as on the return passage, with a more northerly route, she cleared half-a-dozen signals with no delay.
	Air Communications.
	2.  The question of H/F homing was fully discussed in my remarks on the last report of E.G.40. (Convoy S.C.128.)
	H/F D/F.
	3.  Paragraph 8 of covering letter.  This definite information of several Series being used at the same time during an attack on a convoy should be promulgated by Admiralty.