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The Loss of SGB 7


Written by David Purvis: Published 21st July 2009


The story begins on the afternoon of 12th September 2008 when the Buccaneers aboard Channel Diver skippered by Steve Johnson dived a site in the Baie de la Seine, partially identified as the SGB 7. On the wreck at 32 meters visibility was a good 10 meters allowing plenty of opportunity to look around and take stock. Slowly a picture of the ship began to emerge from the tangle of broken wreckage that first greeted us. She had been steel hulled, powered by a single boiler driving two large steam turbines and was full of small calibre main armament and belted large calibre machine gun type ammunition.

A small battle in a big war

It was obvious this was the wreck of a small Second World War vintage warship, which judging by the extent of the debris field and damage had come to a catastrophic end.There were plenty of artifacts lying around including a Navy issue earthenware rum flagon but so far no clues as to who she was. Then came the find that was to provide the key to proving the ships identity. Lying amongst the wreckage near the boiler was a brass engine plate complete with the maker’s name and the serial number 4196. Originally this had been attached to a 4000hp steam turbine reduction gear unit manufactured by Metropolitan Vickers Electrical Co in Manchester.

a earthenware jar which served as rum flagon lying on the sea floor
This naval issue rum flagon is seen lying amid the wreckage on the sea floor

Metropolitan Vickers

This company commonly called Metrovic, had been one of the country’s leading heavy electrical equipment manufacturers since the 1920s. During the second world war Metrovic not only famously worked in collaboration with A.V. Roe to build the highly successful Manchester and Lancaster bombers, but also supplied a range of steam turbines for use in a wide variety of fast merchant and naval ships.

Crucially though, their 4000hp steam turbines were specifically designed for use in a new class of steam gun boat being designed by William Denney and Brothers in Dumbarton. These Denny designed Steam Gun Boats (SGB) were ordered by the Admiralty in late 1940 for use by the Royal Navy’s Coastal Forces specifically to hunt German E-boats and coastal convoys off the French and Dutch coasts.

a brass engine plate showing the manufacturers name recovered from the seabed
This Metropolitan-Vickers brass engine plate served to identify the wreck as SGB 7

Denny Steam Gun Boats

Typically Denny SGBs were 144 ft long, 20ft wide, weighed 165 tons and had a crew of 27. Fitted with twin Metrovick 4000hp geared steam turbines they were designed to have a top speed of 37 knots and were capable of high speed maneuvers even in heavy seas. Armed with one 3” gun, two single 6-pdr guns, two single 20mm Oerlikon cannon and twin machine guns located in turrets either side of bridge they also carried two torpedo launchers mounted on the foredeck and two depth charges. They were the 'battleships' of the British Coastal Forces and in action E-boat commanders respected them almost as much as destroyers.

SGBs had several distinct drawbacks though when compared with their petrol driven cousins the Motor Gun Boat and the Motor Torpedo Boat. Firstly, although steam turbines had the advantage of quietness and reduced risk of fire, they also required a large hull to accommodate them. Large wooden hulls were not suitable for mass production so steel had to be used instead. This meant SGB construction could only be undertaken in the larger yards which were already hard pushed to produce urgently required convoy escorts. As a result, of the sixty SGBs ordered, only seven were actually completed and entered into service.

denny steam gun boat
A Denny Steam Gun Boat of Coastal Forces

Secondly, an SGB required more fuel and crew to function relative to a petrol powered boat, with the added disadvantage that whereas a petrol boat could start from cold and get away immediately, the SGB had to raise steam before it could move; not a happy position to be in when most coastal forces actions lasted less than 20 minutes from “sighting to sinking”. Thirdly and perhaps most importantly, to save weight and maximise speed their hulls had to be light i.e. thin. As a result their engines were easily damaged by shell splinters etc. quickly rendering the boat helpless.

Over time the addition of protective plates around the engines overcame this problem but as we shall see this modification came too late for one of them.The added protection also carried an operational price as their top speed was reduced to 30 kts placing them at a distinct disadvantage when seeking to engage their E boat quarry. All the completed SGBs came into service by August 1942 and formed the 1st SGB Flotilla based at HMS Aggressive in Newhaven, Sussex.

part of the wreck of steam gun boat number seven
Part of the wreck of SGB 7 lying on the seabed

Despite their faults these ships had a distinguished war record participating in numerous actions including the Dieppe raid and earning themselves the nickname 'The Buccaneers' due to their cavalier and highly individual operating styles when engaging enemy forces. In 1943 their new flotilla commander Peter Scott (later Sir Peter Scott of ornithological fame) replaced the boat’s numbers with names starting with Grey: HMS Grey Seal, HMS Grey Fox, HMS Grey Goose etc.

By 1944 however, the E-boat threat had reduced and the SGBs day was largely done. The boats were converted to fast minesweepers and with the exception of SGB 9 (Grey Goose), sold off after the war. SGB 9 remained in service as a trials vessel until she to was sold off in the late 1950s.

The Loss of SGB 7

Despite being in regular action for over 3 years the 1st SGB Flotilla only ever lost one ship, SGB 7. She entered service with the 1st SGB Flotilla in March 1942 under the command of T/Lt Ronald Lewis Barnet RN, a French national who had escaped to Britain and joined the Navy after the fall of France. Her first Lieutenant was T/Lt William James Weir RNVR. She was reported sunk in the early hours of 19th June 1942 following an attack on a German convoy in the Baie de la Seine whilst on patrol with SGB 8 and the destroyer HMS Albrighton.

part of the wreck of steam gun boat seven lying on the seabed
Another shot of wreckage from SGB 7 lying on the seabed

An extract from The Times dated Tuesday 23 June, 1942 entitled Night action in Channel – enemy supply ship torpedoed - Fights with E boats reported the action and the loss of SGB 7 as follows.

The Admiralty issued the following announcement last night (22/06/42). In the early hours of last Friday morning (19/06/42) one of our patrols in the English Channel under the command of Lt. Commander R J Hanson RN sighted an enemy convoy consisting of two supply ships escorted by an armed trawler and at least half a dozen E-boats. Our patrols at once attacked; the larger of the two German supply ships was hit by torpedo and some of the E-boats were hit by gun fire. One of our coastal patrol craft commanded by Sub Lieutenant R Barnet RNVR did not return from this engagement and the Admiralty Board regrets she must be considered lost. The Germans have stated that some of her crew were picked up and are prisoners of war…
an extract from the times newspaper of june 1942
This extract from The Times newspaper of June 1942 carries news of the action (highlighted in yellow) in which SGB 7 was sunk

Sir Peter Scott also briefly described her loss in his book Battle of the Narrow Seas.

During the latter half of June two new types of Coastal Forces craft (SGB 4 & SGB 7) had just come into the arena when they experienced action…A few days later on the 18th June while operating in the company of a Hunt class destroyer HMS Albrighton they sank a merchant ship in the Baie de la Seine. Lt R Barnet RN who fired the successful torpedo lost his boat and was himself taken prisoner with nearly all his crew.

Navy records show that Lt Commander Hanson was awarded the Distinguished Service Cross (DSC) for gallantry during this engagement. He went on to be awarded a DSO for gallantry during the Dieppe raid in October 1942 commanding HMS Albrighton, gaining a bar in March 1943 as a result of an action against a German convoy whilst commanding the destroyer HMS Ulysses.

T/Lts Barnet and Weir from SGB 7 were mentioned in dispatches in recognition of their bravery that night as were Lts Ritchie and Griffiths from SGB 8, (Lts Ritchie and Griffiths were subsequently awarded DSCs for gallantry fighting R boats off Boulonge in September 1942, Lt Griffiths gaining a bar in May 1945 as a result of an action against German E-boats).

The citation in respect of T/Lt Weir reads:

T/Lt Weir, First Lieutenant HM SGB 7: Responsible for the scuttling of the ship because of its new design by setting charges and blowing it up; spent 1 hour in the water.

Sadly four of SGB 7’s crew were reported missing presumed killed. Navy records confirm the German claim that members of SGB 7’s crew were picked up and taken prisoner following this action. Some, including T/Lt Weir were sent to Marlag prison camp at Westertimke near Bremen but what precisely happened to them thereafter isn’t known.

On 21st January 1945 however, the ratings were marched westwards ahead of the advancing Russians enduring the privations of a 1000 mile trek through Czechoslovakia and Poland before being liberated by the Americans. On 9th April 1945 the remaining officers at Marlag camp were forced onto the road. Unfortunately allied fighters, mistaking them for German infantry, shot up the column killing some of the POWs and wounding many more.

T/Lt Weir survived to be liberated at Lubeck later that year but there is no record of what happed to T/Lt Barnet. Returning to the supply ship torpedoed by SGB 7, the most likely candidate for this vessel is the SS Turquoise which now lies in 40 meters a few miles North West of SGB 7 though definitive proof is very hard to find.

SS Turquoise

The Turquoise was a 278 ton Belgian registered coaster built in 1932 by John Cockerhill in Antwerp to work between Ostend and Tilbury. At the start of the second world war she was captured by the advancing Germans and passed into German naval service as an armed coaster number T45. It’s apparent that after conversion she became a heavily armed ship with at least 1 x large gun on the foredeck, 2 x twin barreled quick firing guns (possibly heavy machine guns or cannon) housed in turrets just forward of the bridge and 2 x further single guns on her afterdeck. 15 of her crew are visible in the image. In the accounts of her sinking written by John Liddiard and Mark James both say she was sunk on 19/06/1942 by a torpedo fired by a British/Free French steam gun boat. Mark James goes further naming the SGB involved as SGB 7.

SS Turquoise a Belgian trawler pressed into Kreigsmarine service as T45
SS Turquoise, a Belgian trawler, armed and pressed into Kreigsmarine service as T45
A drawing of the wreck of SS Turquoise lying on the sea bed
Sketch of wreck of SS Turquoise by Max Ellis

There you have it, the story of one small battle typical of those fought nightly by British Coastal Forces to deny the German navy control of the channel. Amazingly in less than 30 minutes at least four men died, two ships were sunk and four gallantry awards were earned. So next time you dive these wrecks please spare a thought for T/Lt Barnet and his missing crew mates as well as those lost on the Turquoise. Then tip your hat and wish them 'God Speed' before going on your way, they’ll appreciate that.

the buccaneers diving team aboard their dive vessel
The Buccaneers diving team who discovered the wreck of SGB 7 in 2008

© David Purvis