Convoy HG 73

Convoy HG 73 was a trade convoy of merchant ships during the second World War. It was the 73rd of the numbered HG convoys Homeward bound to the British Isles from Gibraltar. The convoy departed Gibraltar on 17 September 1941 and was found on 18 September by a Focke-Wulf Fw 200 Condor of Kampfgeschwader 40 (KG 40). The 25-ship convoy was attacked by five U-boats of 1st and 2nd U-boat Flotillas, operating out of Brest and Lorient, respectively. They were initially assisted by Italian submarines Luigi Torelli, Morosini and Leonardo Da Vinci, that were en route to the Mediterranean. Nine ships were sunk from the convoy before the submarines exhausted their torpedo inventory on 28 September. Surviving ships reached Liverpool on 1 October.

Escorts
When leaving Gibraltar on 17 September the convoy was protected by the following escorts:-
 * British destroyer HMS Vimy (D33) (LtCdr H.G.D. de Chair, RN) until 22 September
 * British escort destroyers HMS Duncan (D99) (LtCdr A.N. Rowell, RN) and HMS Farndale (L70) (Cdr S.H. Carlill, RN) until 20 September
 * British sloop HMS Fowey (L15) (LtCdr L.C.A. Leefe, RN)
 * British corvettes HMS Begonia (K66) (T/Lt T.A.R. Muir, RNR), HMS Gentian (K90) (Cdr R.O. Yeomans, RD, RNR), HMS Hibiscus (K24) (LtCdr C.G. Cuthbertson, RNR), HMS Jasmine (K23) (LtCdr C.D.B. Coventry, RNR (retired)), HMS Larkspur (K82) (Lt S.C.B. Hickman, RNR), HMS Myosotis (K65) (Lt G.P.S. Lowe, RNVR), HMS Periwinkle (K55) (LtCdr P.G. MacIver, RNR) and HMS Stonecrop (K142) (Lt J.V. Brock, RCNVR)
 * British fighter catapult ship HMS Springbank (Capt C.H. Godwin, DSO, RN (retired)) until lost on 27 September.

On 20 September, the convoy was joined by the following:-
 * British destroyers HMS Wild Swan (D62) (LtCdr C.E.L. Sclater, RN) until 22 September, HMS Highlander (H44) (Cdr S. Boucher, RN), until 26 September, and HMS Wolverine (D78) (LtCdr J.M. Rowland, RN)

18 September
One day after the had left Gibraltar, a Focke-Wulf Fw 200 Condor aircraft of KG 40 located the ships off Cape St. Vincent but was chased away by the Fulmar fighter from HMS Springbank. Four Italian submarines, on patrol west of Gibraltar, were ordered to search for it: Leonardo Da Vinci (CC Ferdinando Calda), Alessandro Malaspina (TV Giuliano Prini) *, Morosini (CC Athos Fraternale) and Luigi Torelli (CC Antonio De Giacomo).

19 September
Morosini made the first contact with the convoy, but one of the electrical engines broke down and the submarine returned to base. The same day, GS U-371 sighted the convoy as well, but the U-boat was en route to the Mediterranean and ordered to continue its mission.

20 September
In the evening, Torelli found the convoy and was badly damaged by depth charges from HMS Vimy when she tried to attack the convoy during the night of 21/22 September, forcing the submarine to abort its patrol.

23 September
Da Vinci sighted the convoy again and kept contact for GS U-124 (1940) and GS U-201, which were directed to it by the BdU, coming from the battle against Convoy OG 74. The next day, a Fw200 aircraft located the convoy and sent homing signals.

24 September
During the following night, only U-124 reached the convoy and reported unsuccessful attacks on a cruiser sailing ahead of the convoy, possibly misidentifying the fighter catapult ship HMS Springbank and a destroyer, before sinking the first ship. The U-boat was joined by GS U-203 the next night and together they sank five ships, while U-201 also reached the convoy, but was chased away by the escorts.

26 September
In the night of 26/27 September, all three U-boats attacked again sinking two more ships and HMS Springbank, while the outbound U-205 made contact but lost the convoy in bad visibility.

27 September
Allied flying boats arrived to screen the convoy and they kept the most U-boats at distance, only U-201 managed to attack the following night, sinking another steamer. Three of the four participating U-boats were now out of torpedoes and the BdU ordered U-124 and U-201 to return to base, while U-203 shadowed the convoy for U-205, but this U-boat had been bombed and damaged in the evening on 28 September and the operation was broken off at dawn on 29 September.

Conclusion
The three attacking U-boats claimed the sinking of 10 ships with 62,000 tons, however the actual tonnage lost was just 25,218 tons, plus one corvette possibly sunk and another ship damaged. This reflects the reappearing problem of overestimating the targets in the Gibraltar convoys, the commanders mistaking coasters with the engine aft as tankers and claiming normal ship sizes for North Atlantic convoys, while the average size of the ships in the convoy HG 73 was about 2,200 GRT, for example.

On this occasion the cooperation between the U-boats and air reconnaissance of the Luftwaffe worked as intended, the Fw200 aircraft of KG 40 being in contact with the convoy after it left Gibraltar, sending homing signals and helping the U-boats to get into a favorable position for the night attacks. Moreover, the Italian submarines were complimented by the BdU for their shadowing work in the early phase of this battle. None of the submarines reported a successful attack on the convoy, but a Fw200 reported two ships in sinking condition and one burning ship behind the convoy on 24 September, so they were wrongly credited to Malaspina, which did not return from her patrol. Allied sources mention no ships being lost or damaged in this area on that day.

Italian Submarine Malaspina
Unknown at this time was that Malaspina had already been lost on 10 September, bombed and sunk with all hands by the Australian Sunderland aircraft W3986 (10 Sqdn RAAF/U, pilot F/L A.G.H. Wearne, RAAF) while outbound in the Bay of Biscay in position 46.38333°N, -11.36667°W. The submarine was reported missing after leaving Bordeaux on 7 September and for some time it was thought that she had been sunk by the British destroyer HMS Vimy during the night of 21/22 September in the vicinity of convoy HG 73, but this attack was in fact directed against Torelli. Her fate was revised in March 2004 by Dr. Axel Niestlè and Eric Zimmerman.

==Ships in the convoy ==