HMS Thorn (N11): A Highly Effective Boat, Lost Off Crete

Laid Down at Birkenhead

HMS Thorn was built by Cammell Laird at Birkenhead, laid down on 20 January 1940, launched in March 1941 and commissioned on 26 August 1941 under Lieutenant Commander Robert Galliano Norfolk, a T-class submarine that went on to compile an impressive record in the Mediterranean.

A Highly Productive War

Across eight war patrols between October 1941 and August 1942, Thorn sank the German tanker Campina on 30 December 1941, the Italian merchant Ninuccia on 28 January 1942, the Italian auxiliary patrol vessel AS 91, known as Ottavia, on 5 March 1942, and the Italian transport Monviso.

Eight patrols in ten months is a hard rate of work, and that list is the useful sort of record rather than the glamorous sort. A tanker is worth more than a warship to a submarine in that campaign, because Rommel's army in North Africa ran on fuel that had to cross the Mediterranean in ships, and every tanker on the bottom was a column of tanks that did not move. The Campina, sunk three days after Christmas 1941, was exactly that kind of target.

Two of those eight patrols also carried what the records call special operations, one in the Aegean in November 1941 and one in the Adriatic the following January. That is the usual formula for putting people ashore on an enemy coast at night and, if things went well, collecting them again later. It is worth knowing that a boat with this shooting record was doing that work as well, because it did not come with any reduction in the rest of the job.

She also had one captain and only one. Robert Norfolk took her in July 1941 before she commissioned and was still in command on 6 August 1942, which means every patrol, every ship on that list and the Medusa were his, and so was the last morning. Boats that lasted longer went through several captains. Thorn had a single one for the whole of her life, and he did not outlive her by a minute.

The AS 91 is the odd one out and the most dangerous. An auxiliary patrol vessel is a trawler or a small steamer with a gun and depth charges bolted on, and her whole job is hunting submarines. Sinking one means Thorn attacked a ship that was actively looking for her, which is a fight nobody starts unless they have to or unless they are very confident.

Her most notable success came on 30 January 1942, when she sank the Italian submarine Medusa, a significant kill against an enemy underwater adversary rather than the surface shipping that made up the bulk of most patrol reports.

Look at where she did it. The Medusa went down off Promontore in Istria, which is the southern tip of the peninsula at the very head of the Adriatic, closer to Venice than to anywhere the Royal Navy held. Thorn had taken a submarine the whole length of the Adriatic, up a long narrow sea with Italian coastline on one side and Italian-held coastline on the other and no way out except the way she came in, and made an attack at the top of it. That is not a patrol area. That is a raid.

The Medusa was an Argonauta-class boat of 680 tons on the surface, a small coastal submarine of a type Italy had built a great many of. Thorn fired four torpedoes at 3,500 yards and one hit. Fifty-eight of the Medusa's people were killed, which on a boat that size is very nearly everybody, and it is worth holding that number next to the one at the end of this story.

One submarine killing another was uncommon and almost always happened like this, with the victim on or near the surface and the attacker dived and unseen. HMS Telemachus shows the same thing done in the Malacca Strait two years later. What it never involves is a fair fight, and the men on the receiving end generally never know what has happened to them.

Lost Off Southern Crete

Thorn departed Beirut on 21 July 1942 for a patrol near Tobruk, her eighth, and failed to return by her ordered date of 11 August 1942.

The most probable account holds that on 6 or 7 August she encountered the Italian torpedo boat Pegaso, then escorting the steamer Istria from Benghazi off southern Crete; Pegaso detected a sonar contact and carried out seven separate depth-charge attacks before losing contact, and it is believed this action accounted for Thorn's loss.

Sixty-One Men, and a Ship With the Wrong Reputation

One detail usually gets left out of that account and it changes the shape of it. Pegaso did not simply stumble on a sonar contact. At about half past twelve on 6 August, thirty miles or so south-west of the islet of Gavdos, one of the aircraft escorting the convoy was seen to strafe the surface of the sea. Four minutes later Pegaso had a submarine on her instruments. The aircraft found Thorn; the torpedo boat killed her. It was the combination that did for submarines by 1942, and it is the reason the Mediterranean became unworkable for them.

Seven attacks is also a great deal of patience. A depth-charge run is a guess at a moving target in three dimensions, and doing it seven times means a captain who would not let go. Every man in Thorn was killed: sixty-one of them. Six months earlier she had killed fifty-eight men in the Medusa, and the two figures sit almost exactly on top of each other, which is as good a description of that campaign as any.

Pegaso herself is worth a word, because she has ended up famous for the wrong thing. For decades she was credited with sinking HMS Upholder on 14 April 1942, the most successful British submarine of the war, commanded by the most decorated officer in the fleet. That attribution has been steadily taken apart: Upholder was probably nowhere near the place Pegaso attacked, and the likeliest answer is that she was lost in an Italian minefield.

So the small Italian escort best known for a kill she probably did not make almost certainly did make this one, and hardly anybody has heard of it. Thorn was a genuinely effective boat, and she is remembered, when she is remembered at all, as a footnote to somebody else's reputation.

Her wreck has never been found, and until it is, the precise circumstances of her final hours cannot be confirmed with absolute certainty, a quiet uncertainty that still surrounds one of the more successful British submarines lost in the Mediterranean campaign.

The uncertainty is not going to be resolved soon. Thorn is somewhere in deep water south-west of Crete, in a stretch of the Mediterranean that drops away fast and has never been systematically searched, and there is no particular reason for anybody to look. Boats found in recent years have generally been found in shallower water and closer to shore. HMS Urge turned up after seventy-nine years off Malta and settled an argument that had run since 1942, so it is not impossible. It is simply not likely.

Until then she is still on patrol, in the phrase the submarine service uses for its missing boats, and the sixty-one names are the whole of the memorial. Her last patrol was her eighth in ten months, and she had been in commission for less than a year. The T boats that came later, HMS Thule among them, inherited the sea she helped make untenable for the other side and fought a very different war in it.