Wreck Tour 77: HMS Northcoates

HMS Northcoates Wreck Tour
HMS Northcoates Wreck Tour

This armed trawler is a big attraction for divers off Sussex, and rightly so, says JOHN LIDDIARD. MAX ELLIS drew the picture

THE WORLD WAR TWO ARMED TRAWLER HMS Northcoates is one of Littlehampton’s more popular wrecks, and an obvious candidate for a Wreck Tour. This connection was also made by Mole Valley SAC, which has adopted the wreck and helped me put the sketch together.

On a wreck this size, lying on a 26m-deep seabed, a dive could start anywhere, so for convenience I will begin our tour at the bow. An A-frame across the bow, and hinged down to the seabed (1), is the attachment point for the Northcoates’ minesweeping gear.

12-pounder gun at the bow.
12-pounder gun at the bow

While on the seabed, just off the port side of the bow you can see the slowly rotting remains of a wooden mast (2) partly buried in the sand.

Back to the wreck and the mine-sweeping gear, at the tip of the bow (3) is a roller to guide cables over it. The anchor-winch (4) would have been to assist with laying and retrieving cables, in addition to raising the anchors.

At the back of the bow deck, the main 12-pounder gun (5)  stands above the skeleton of its platform, the barrel pointing upwards and to starboard.

Below the gun, a hatchway forward into the forecastle (6) is low and partially silted. Exploring inside should not be undertaken lightly.

Onto the main deck, a collapsed derrick on the port side (7) and its partner, still upright on the starboard side (8), would have been used to launch and recover the mine-hunting ‘fish’.

A-frame from the mine-hunting gear at the bow
A-frame from the mine-hunting gear at the bow

With all these references to mine-hunting equipment, perhaps I should explain how it all fits together. By WW2, mines were becoming more sophisticated than simple contact-triggered devices.

Magnetically triggered mines would be moored below the keel depth of ships, and a sufficiently large mass of steel passing above would create a magnetic field strong enough to trigger the mine.

Rather than detonating against the bow of a ship, as a contact mine would, a magnetic mine would detonate beneath the centre of the ship, and break its back.

But there are other ways of generating a magnetic field strong enough to trigger a mine, one being to pass an electric current along a cable, and this effect was exploited for minesweeping. On the Northcoates, cables would be passed over the bow to the A-frame, then trailed out to either side of the ship by the fish.

A pair of diesel generators (9) would provide the electricity to create the magnetic field and detonate mines off to either side of the minesweeping ship. Of course, this could all go horribly wrong if a minesweeper passed directly over the mine, which is what made minesweeping such a dangerous business.

One of two diesel generators that would have powered the mine-hunting gear
One of two diesel generators that would have powered the mine-hunting gear

Continuing aft, behind the diesel generators is the front of the wheel-house, now fallen level with the main deck and skewed to port in the process, followed by the steering engine (10).

Heavy cables (11) bundled along the port side are the final remaining component of the minesweeping gear.

The Northcoates’ wheelhouse was wooden and built up above this area of the hull, although now this is just a gaping hole in the wreck, with the boiler at the rear (12).

More cables from the minesweeping gear (13) lie draped across the boiler from the starboard side, a coiled bundle at the end resting over the port side of the hull. Behind the boiler, the Northcoates’ engine (14) is an unremarkable three-cylinder triple-expansion engine.

Staying on the port side, a platform carrying dual 0.5in machine-guns (15) has also fallen to port. It was originally located on the roof of the deckhouse, above the engine.

Our route now drops over the port side to the seabed and below the stern to the propeller (16). This is iron or steel with four blades, just over half of it above the seabed. Behind the propeller, the rudder (17) 
is angled to starboard.


Continuing round the stern, take time to look at the marine life growing on the hull. HMS Northcoates is a Marine Site of Nature Conservation, so designated for the great variety of marine life on and about the wreck. For example, it is about as far east in the English Channel as Devonshire cup corals can be found.

Heading back along the starboard side, just aft of the engine you come across the toilet (18). With the remains of any structure above fallen to port, it is possible to swim below the open deck ribs here and inside the stern (19), light entering through the ribs above and through holes rotted in the hull.

Having travelled aft mostly along the port side, returning to the bow along the starboard side will show where the hull has broken out just forwards of the boiler (20), and the curved remains of the funnel mostly buried in the sand.

On a wreck this small, it should be easy to relocate the shotline wherever it is on the wreck. For most divers, decompression stops are likely to be short enough that they can be completed on the line before the current builds up enough to make deploying a delayed SMB necessary.


For years after divers discovered the wreck off the Sussex coast, they could only call it the Armed Trawler. It was obvious that it was just that, but no one knew its proper name, writes Kendall McDonald.

The wreck sat upright on the 26m-deep sandy seabed, with just a slight list to starboard. Those first divers found a 12-pounder gun on the foredeck with the date ‘1939’ on the breech, and a box of shells nearby were marked ‘Enfield Cartridge Company’ and dated ‘1942’. But they still couldn’t find the vessel’s name.

A tangle of sweep-wire hung from a derrick on the bow and twin 0.5in machine-guns were mounted on the port side near the stern. And still, despite all the diving done on it, no one could identify the wreck – until divers from Ruislip & Northwood BSAC found a set of numbers stamped on the breech of the 12-pounder, which set them off on research that would finally reveal all.

The Armed Trawler had been built of steel for the Royal Navy in 1918 by Cocks & Co at Falmouth, and was launched the following year as the 277-ton HMS George Corten, 38m long with a beam of 7m. Its three-cylinder triple-expansion engine produced 87hp.

The vessel had cost £21,000. The Navy sold it in 1921 when it was ordered to slim down Britain’s naval forces, and it became a fishing trawler called Zencon. In 1939, at the start of WW2, the Navy took it back, renamed it HMS Northcoates, and put it on minesweeping duties.

It served as a sweeper for all the war years until, on 1 December, 1944, its engine failed and it was taken under tow. The next day the wind and sea increased so much that HMS Northcoates foundered. The Navy listed the loss as due to ]“stress of weather”.


GETTING THERE: Once in Littlehampton, boats are berthed on the pontoon where the riverside road meets the seafront road, by the Nelson Hotel.

TIDES: Visibility is best at low-water slack, six hours after high-water Littlehampton.

HOW TO FIND IT: The GPS co-ordinates are 50 39.723N 000 35.401W (degrees, minutes and decimals). The bow points to the south.

DIVING: Our Joy, skippers Daniel & Vernon Parker, 01243 553977, 07850 312068.

AIR: Arun Nautique (air) 01903 730558; Ocean View Diving Services (air, nitrox and trimix) 01243 601000.

LAUNCHING : The closest slipway is at Littlehampton.

ACCOMMODATION: B&B at the Nelson Hotel, conveniently located next to the charter-boat pontoon.

QUALIFICATIONS: Ideally suited for the average spread of qualifications on a club trip.

FURTHER INFORMATION: Harbourmaster 01903 721215. Admiralty Chart 1652, Selsey Bill to Beachy Head. Ordnance Survey Map 197, Chichester and the South Downs, Bognor Regis and Arundel. Dive Sussex by Kendall McDonald. Mole Valley SAC.

PROS: It’s quite hard to beat a good armed trawler.

CONS: Can get a bit crowded, especially if more than one boatload of divers is on the wreck.

Thanks to Vernon and Daniel Parker, Tim Walsh, and Mole Valley SAC.

Appeared in Diver July 2005


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