M O S T  S E C R E T  
   
 
REPORT ON CONVOY ONS 5 - LIST OF CONTENTS.
     
  1.  Comments of Senior Officer, Close Escort.  
  2.  Report of Proceedings - Senior Officer in H.M.S. DUNCAN.  
  3.  Report of Proceedings - Senior Officer in H.M.S. TAY.  
     
  Enclosures:  
  A.  Reports of Proceedings of Individual Ships  
       1.  H.M.S. VIDETTE.  
       2.  H.M.S. SNOWFLAKE AND SIGNALS.  
       3.  H.M.S. SUNFLOWER.  
       4.  H.M.S. LOOSESTRIFE.  
       5.  H.M.S. PINK AND REPORT FROM MASTER OF S.S. WEST MADAKET.  
       6.  Rescue Trawlers.  
  B.  Narratives of attacks on submarines by individual ships.  
  C.  Appendix on Aircraft cooperation by H.M.S. DUNCAN.  
  D.  Appendix on fuelling and fuel consumption.  
  E.  Signals.  
  F.  R/T log of H.M.S. TAY - period 4th-6th May, 1943.  
  G.  H/F D/F report.  
  H.  Track Charts and Barograph chart.  
  I.  Recommendations.  
     
     
     
     
     
     

 

 

 
 
     
  S E C R E T  
   
 
ONS 5 - COMMENTS OF SENIOR OFFICER, CLOSE ESCORT
     
          It was a bitter blow to have to leave the convoy on May 3rd when it was still in the danger area.  No other course of action was possible.  The weather throughout was extremely bad and consistently adverse.  I took every precaution to fuel at every available opportunity and was indeed fortunate to get a short lull in the gales to top up Duncan.  Oribi and Vidette.  The convoy took 16 days to get from Oversay to the Westomp in case further comment on the weather is possible or necessary, I enclose the barograph trace for the fortnight's trip.  I suggest, with support groups requiring fuel, escort oilers should not sail with less than 1000 tons of fuel available for escorts.  British Lady had only 500 to 600 tons.  
     
  2.  Series of night attacks on 28 - 29 April.  
          A most successful night.  DUNCAN, on her maiden escort with the Group.  Found herself in the fortunate position of being able to detect and attack no less than four separate submarines in one hour and fifty minutes.  Two of these attacks were promising though as usual in these affrays, there was no time to seek evidence.  From examination of the plot, it seems likely that the U-boat of incident "Dun two" was the same one attacked by SUNFLOWER in incident "Sun one".  
          There must have been five or six U-boats involved, in addition to the one attacked by DUNCAN in daylight (incident Dun One) and the the one which carried out the successful submerged attack next morning.  
          It also appears probable that the three boats involved in incidents "Dun three", four and five must have been attempting some sort of co-ordinated attack.  
     
  3.  Successful submerged attack on the convoy on 29th April.  
          The U-boat which transmitted at 0338, bearing 330 must have dived before VIDETTE who was sent out after her, was able to sight.  VIDETTE was back in station five minutes before the attack, but the U-boat must have dived under or between DUNCAN and VIDETTE and fired from between the columns.  A bold effort, and it was disappointing that my, for once, correct and timely counter actions did not prevent the attack.  
          It also appears from study of the plot and considerable thought, that my appreciation of the firing position was not correct, as although she must have fired from the starboard side, it seems likely that it was from close range and that N. Gem's contact might have been the U-boat.  I investigated this contact carefully, however, before leaving it.  
     
  4.  Two Successful Daylight Attacks on 5th May.  
          In both cases, the submarine came down from ahead of centre of convoy and fired from between the columns.  In the second attack, it was most unfortunate that "Tay's in Apples" A/S went out of action 30 minutes before the firing of torpedoes, as the submarine must have dived under her.  It would have been better to have exchanged stations on the screen.  Both "Artichokes" probably detected submarine, one of which OFFA considers destroyed.  
     
  5.  Successful Night Attacks on 4th - 5th May.  
          The first attack was on a straggler, six miles astern.  LOOSTRIFE was sent back to assist NORTHERN SPRAY with her.  This left only 4 escorts on the close screen.  During the next attack, which was from both bows, at least two U-boats came  
     
                                                                                                                             in/  
     
     

 

 
 
     
 
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  5.  (Continued)
  in on the starboard bow, and the one which VIDETTE first attacked, made a gap through which the second could deliver her attack.  During the third attack, the submarine probably got in on the port quarter.  
     
  Both "Half-Rasberries" detected the U-boats responsible.  
     
  6.  Unsuccessful Night Attacks on 5th - 6th May.  
          No comment is required; the results were magnificent.  
     
  7.  Stationing of Night Screens,  Nights, 4th - 5th, 5th - 6th May.  
          I feel strongly that OFFA with 272 R.D.F. should have been stationed on the close screen, and not five miles on the bow.  This would have brought the number of ships with 271 or 272 R.D.F. up to six; which is the minimum required to form an iron ring around a small convoy.  E.G.3 concurs with this.  In addition, ORIBI with 291 R.D.F. should have been stationed at least 8 miles clear, as it was, she created considerable confusion.  
     
  8.  
          H/F D/F was again invaluable in providing reliable warning of most attacks and in actually causing several day sightings.  The plan, used on the nights 29-30 and 30-1, of dropping charges on the estimated firing positions of U-boats detected by H/F D/F close to the convoy appeared to be successful in that no attacks developed.  This may be wishful thinking, however, and there may be some other reason.  After their experiences of the night 28-29, the first U-boat pack had both decreased in numbers and grown more timorous.  
          This was DUNCAN's operators first escort of any kind and the H/F D/F officers first experience of FH4.  Their performance was highly commendable.  TAY and ORIBI also produced good results, though intercommunication was not altogether satisfactory.  This is being rectified.  From careful analysis by my H/F D/F and Signal Officer of the third escort group, it is clear that on the 4th, 5th, 6th May, U-boats were using simultaneously 2 series; series 2, line 1; series 2, line 2,  U-boats to starboard and astern used line 1, and ones ahead and to port line 2.  It is, therefore, probable, that two separate packs were involved.  This is a new plan to me.  Admiralty estimated 25 U-boats in contact.  For further details see H/F D/F report, Appendix H.  
     
  9.  Route.  
          It is felt that the convoy was routed too far North into ice and gales, which prevented fuelling of escorts and scattered an already very slow convoy.  With all close escort fitted 271 and with U-boats fitted with R.D.F., heavy weather is no longer an advantage to the convoy; and on the contrary, in good weather, with efficient close screen in correct station, successful night attacks on the surface are impossible, as has been demonstrated by the group during passage of the convoy HX 231 and ONS 5.  
     
  10.  Air Coverage.  
          During the period of first sighting and of calling up the pack, air cover was concentrated on SC127, so that it was doubly satisfactory to get away with only one ship lost  
     
                                                                                                           during/  
     
     

 

 
 
     
 
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  10.  (Continued)
  during a period of no coverage.  As usual, Liberators later put up magnificent performances in flying very long distances in appalling weather to escort the convoy.  It was unfortunate that they were laid on too late to get any sightings.  The communications and general ability of these machines is noteworthy.  
          Air cover from Newfoundland was scanty due to fog at base, but two good attacks were made by Cansos of the R.C.A.F. near the convoy.  
     
  11.  
          H/F ship intercommunication by day was impossible anywhere near Greenland on any frequency.  It was noted that the U-boats had the same trouble, and their gear is better than ours.  I feel that Admiralty is inclined prematurely to assume that a convoy in this particular area is not being shadowed because they cannot hear the U-boats.  This fact may be due to H/F conditions.  Further details are given in Appendix G, H/F D/F report.  
     
  12.  
          The support force were of great assistance, and it was unfortunate that the third escort group could not stay longer.  EG3 was most cooperative and helpful, and OFFA and ORIBI undoubtedly made a great difference to the situation during the period 4th - 6th May.  In the short time with the group, EG3 also did everything possible to assist.  
     
  13.  
          The Commodore gave every assistance.  He was handicapped by an unsuitable ship and the convoy, although they did their best, were unable to compete with the weather.  B7 group again proved themselves to be equal to coping with the enemy until the weather had scattered the convoy.  Few signals had to be made, and all ships worked very hard under most adverse conditions.  
          Lieutenant Commander Sherwood of HMS. TAY, handled a very dangerous situation with ability and coolness.  I consider he did exceptionally well, being ably backed up by the group.  
     
  14.  
          Preliminary investigation by Captain (D) Newfoundland shows the following claims as reasonable for the whole period of the convoy -  
 
Certainties - SNOWFLAKE
    SUNFLOWER
    VIDETTE
    ORIBI
     
Very Probable - LOOSESTRIFE
    OFFA
    Aircraft of R.C.A.F.
     
Possible - DUNCAN
    PINK
    VIDETTE
    TAY
    SENNAN
    SPEY
    OFFA
 
     
     

 

 
 
     
 
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  Numerous other attacks were made.
  I feel that the enemy, although they sank 13 ships, have been dealt a blow that may have far reaching results on their future tactics which must inevitably increase the proportion of day to night attacks.  While it is difficult to single out one ship of the group, I feel SNOWFLAKE put up the most outstanding performance, carrying out at least 12 attacks and finally bagging a U-boat.  
     
  15.  
          Rescue Trawlers proved of great value and did well.  The Commanding Officer, NORTHERN GEM's suggestion that a doctor be carried is concurred in.  
     
  16.  
          The Commanding Officer, H.M.S. PINK was placed in a very awkward position with his team of stragglers.  
          I think he made an incorrect decision when he remained astern to continue the attack on his submarine at 1000Z on May 5th, but I would have hated to leave it myself.          
     
  17.   
          Recommendations for Honours and Awards will be forwarded under separate cover.