HMS Sea Rover (P218): Hunting Coasters and Gunboats Across the Far East

Built on the Clyde, Sent East

HMS Sea Rover was built by Scotts Shipbuilding and Engineering at Greenock, laid down in 1941 and commissioned on 7 July 1943, an Improved S-class submarine originally carried under a masking pennant number during construction before receiving her operational number, P218.

After working up in home waters, including a patrol off northern Norway, she deployed to the Indian Ocean, reaching Trincomalee in Ceylon in February 1944 to begin a remarkably eventful run of patrols against Japanese forces across South East Asia.

One man commanded her for every one of them. Lieutenant John Peter Angell took Sea Rover in August 1943, three weeks before she was ready, and did not hand her over until March 1945, by which time she had made eight patrols and was in a British dockyard with a temporary bow.

Her first patrol out of Trincomalee opened with a shot at another submarine. On 3 March 1944 she attacked the Japanese boat RO-111 in the Malacca Strait and missed, which is worth noting because a submarine hitting a dived submarine was almost unheard of and it is the one target that can shoot back in the same terms. The same day she sank the Matsu Maru No.1 with her gun, and five days later she torpedoed the transport Shobu Maru, 2,005 tons.

A Busy War in the Malacca Strait and Beyond

Operating through the Malacca Strait, off Sumatra and around Penang, Sea Rover sank the Japanese transport Shobu Maru in March 1944, engaged a train near Lhokseumawe by gunfire, laid a minefield off Penang and sank a Japanese auxiliary gunboat there that May.

Fifty-Nine Shells at a Goods Train

The train deserves rather more than a clause, because shelling a railway from a submarine is not a common entry in anybody's log. It happened on 20 April 1944 off Lhokseumawe on the northern coast of Sumatra, and Sea Rover destroyed the train with fifty-nine rounds of three-inch.

Fifty-nine is a great many. A submarine carries a limited amount of ammunition and every round has to be handed up through a hatch by a chain of men, so a fifty-nine round shoot means a long time on the surface, close inshore, in daylight, off an enemy coast, with the gun crew exposed and the boat unable to dive quickly with the hatch open and ammunition in the casing.

It was worth doing for a reason that has nothing to do with the train. The Sumatran coast road and railway were how the Japanese moved anything that could not go by sea, and by 1944 they could not move much by sea because of submarines exactly like this one. Hitting the railway closed the alternative. The same logic explains the mines: eight of them, laid on 18 May between the Sembilan Islands and the Malayan coast, in a channel a coaster would use precisely because it was too shallow and too narrow for a submarine to work in.

The gunboat Kosho Maru, 1,365 tons, went to a torpedo off the southern entrance to Penang harbour four days after that. HMS Tally-Ho was working the same waters at the same time, and HMS Stonehenge had disappeared north of the Strait weeks earlier.

She survived being depth charged by Japanese escorts that June, taking on a reported two tons of water in the process, and was twice attacked by Japanese aircraft while carrying out air sea rescue duties off Padang without suffering any damage, before moving south to Fremantle in Australia to come under South West Pacific Area command.

Two tons of water is worth translating. It came aboard on 26 June 1944 when Japanese anti-submarine vessels caught her in the Malacca Strait, and the record describes the damage as considerable. Water inside a dived submarine is the thing that kills, not the explosion: it destroys her trim, it makes her heavy so she wants to keep going down, and if it reaches the battery cells and mixes with the acid it gives off chlorine gas.

Two tons is also, on a boat of some eight hundred tons, an amount you can pump out if you are allowed to run a pump, and a pump makes a noise the ship overhead can hear. So the drill is to sit there getting heavier and quieter until the hunters give up, and only then start pumping.

She stayed on patrol and finished it, sinking sailing vessels with demolition charges the next day and again a week later. The next patrol had her doing air-sea rescue off Padang, waiting on the surface for aircrew who might or might not appear, and being bombed twice by Japanese aircraft for her trouble. HMS Shalimar and HMS Thule were doing the same round of small targets, demolition charges and gun actions in the same months.

A Collision in the Java Sea

Her later patrols took her into the Flores Sea and the Java Sea, sinking a Japanese coaster by gunfire in the Makassar Strait that November, before a collision with the Australian corvette HMAS Bunbury on 17 December 1944 brought her active service to a close and sent her home for repair behind a temporary false bow built onto her at Fremantle, and on to the Philadelphia Navy Yard in the United States for a full refit the following spring.

The collision itself happened at twenty-three minutes past midnight, which explains a good deal. Two friendly ships in the same dark stretch of the Java Sea, both blacked out, both looking for Japanese shipping and neither expecting the other, and a corvette has a bow built to survive a knock while a submarine emphatically does not.

What she got at Fremantle was not a repair. It was a false bow, built on so that she could float and steer well enough to cross two oceans, and the restriction that came with it was that only the lowest torpedo tube on each side could be fired. She left on 5 January 1945 and reached Portsmouth on 13 March, which is a nine-week passage from Australia to England in a submarine with a temporary front end.

Then she crossed the Atlantic. Sea Rover arrived at the Philadelphia Navy Yard on 26 April 1945 and was under refit there until 7 September, by which time both wars were over. So both halves of the story are true and neither is the whole of it: Fremantle patched her, Portsmouth received her, and the Americans put her back together.

Across her Far East patrols, Sea Rover is credited with sinking somewhere in the region of nine enemy vessels, a solid tally for a single submarine over roughly a year of active operations.

The vagueness in that number is honest and it is worth defending. Her record is a mixture of named ships with tonnages against them, sailing vessels sunk by boarding party and demolition charge, coasters shot up and left burning, and craft that were simply never identified by anybody on either side. There is no way to add that up to a single figure that means anything.

It also describes the Far East campaign more accurately than a total would. There were no convoys of liners left to sink out there. There was a coast, and traffic creeping along it in anything that floated, and submarines picking it off one wooden hull at a time with a three-inch gun and a stopwatch. One gunner went over the side during a shoot in the Flores Sea on 4 October 1944 and was fished out again, which is about the scale of the drama involved.

Scrapped on the Clyde

HMS Sea Rover returned to Britain and was placed in reserve before being sold for scrap in October 1949, broken up at Faslane, the one detail on which every source consulted agrees without qualification, a fitting enough end for a submarine that had spent much of her active career a very long way from the waters where she was finally laid to rest.