U-Boat U678 was sunk in the English Channel south-west of Brighton, in position 50.32N, 00.23W, by depth charges from the Canadian destroyers H.M.C.S. OTTAWA, H.M.C.S. KOOTENAY and the British corvette H.M.S. STATICE.

 

ADMI/01885

 

SECRET

NO. IW.40/603.OP.                                                                                                                16th JULY 1944

The Director of Anti U-Boat Division.

(copies to: The Commander-In--Chief, Western Approaches.  

The Commander-In--Chief, Portsmouth).

 

ATTACKS BY SHIPS OF E.G.11 OFF BEACHY HEAD JULY 6th-8th, 1944

Submitted.

The report of attacks on Audio contacts by Ships of E.G.11 on July 6th-8th off Beachy Head and of the destruction of U.678 is forwarded. Original recorder traces, track charts and forms S.1203 are attached. The former are badly faded. Ottawa's echo sounding traces were photographed on board and the negatives are held by Canadian Naval Mission Overseas, London.

2.  U.678 was hit by Ottawa's hedgehog at 1059/6. The report of the hedgehog hits are authentic. The U-Boat must have been killed by 1200, though the Senior Officer in Ottawa is considered correct in suspecting a ruse from the cascade of floating books. The explosion of the towed charge at 1230/6 in contact with the hull should however have allayed all doubts of it destruction.

3.  The second firm contact obtained by Ottawa at 2314 within 3000 yards of U.678 is considered to have been a wreck. If it was a second U-Boat it mush have been destroyed, but the echo sounding traces are inconclusive. Insufficient diesel oil was collected from the much battered target to provide a sample and it is thought inconceivable that a second U-Boat would sit still on the sea bottom while such a torrent of explosions was being rained on a spot so close to it. The wooden bar referred to at the end of paragraph four may prove this target's identity, for it very probably came from the second contact.

4.  GENERAL:

(a)  The tactics of Ships of E.G.11 in carefully investigating and hitting hard any suspected target are considered absolutely correct.

(b)  The tactics used by E.G.11 to classify audio contacts are considered very good. Since to classify correctly in the Channel is almost all the battle, it is right that the first ship should go dead allow and bring another ship into contact while other ships distract the U-Boat hydrophone operator by streaming cats on a square search. It is most satisfactory in this long hunt in difficult audio conditions that ho ship every once got in the way of another.

(c)  The difficulties of splitting open a bottomed submarine are of course great, but it is considered that the Senior Officer E.G.11 was over pessimistic as to the results of his attacks. It is inconceivable that a submarine should live to withstand two hedgehog hits and the explosion of a 350 lb. minol depth charge in contact with the hull and the wealth of oil pouring from the target as well as the wood, clothes and books is surely proof enough of the destruction. The necessity therefore for the pulverizing of the dead hull is not surprising.

(d)  The use of an electrically fired towed depth charge is considered desirable for the final destruction of a submarine lying on the level bottom and also for the proving of wrecks. The charge becomes unmanageably at any speed above dead slow and also on an uneven bottom, so the device should only be used after normal depth charge and hedgehog attacks have ensured that the target is on the sea bottom.

(Sd.) G.W.G. Simpson

Commodore (D)

Office of Commodore (D) Western Approaches

Western Approaches Tactical Unit In January 1942 Captain Gilbert Roberts established the Western Approaches Tactical Unit (WATU). It was based on the top floor of the Exchange Building close to Derby House. Roberts and his team studied U-boat tactics and developed effective counter-measures. During the war over 5,000 Allied navy officers attended six-day training courses on anti-U-boat tactics there. The unit greatly improved the performance of escort groups in the Atlantic battle.

 

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   In their war against the U-boats, the British developed an ungainly looking, multi-barreled weapon called the Hedgehog in January 1942 that fired a barrage of 24 -7.2" Mk 6 bombs (called projector charges), each weighing 75 pounds, in an oval pattern over a wide area. Before development of this weapon, submarine-killers employing depth charges had to pass directly over a submerged submarine. The Hedgehog was the first stand-off submarine killing weapon. The bomb was not a rocket, but was propelled up to 250 yards by an impulse charge of smokeless powder. The explosive charge consisted of 30 pounds of TNT, or 35 pounds of Torpex. Destroyer Escorts routinely carried 240 missiles which was enough for 10 launches. A reload took about 3 minutes. The missiles are loaded on cylindrical bars called spigots, six are attached to each cradle, with four cradles in the projector. These cradles are interconnected and can be swung about a fore-and-aft axis by means of a roll-correction gear assembly mounted on a gun-train indicator pedestal. This movement is limited, but allows enough movement to compensate for roll of the ship and to aid in leading the target. The charges are electrically fired by a ripple switch, firing the missiles in pairs every 0.10 seconds, with the highest trajectories being fired first so that all 24 hit the water at about the same time, this minimizing the submariner's reaction time. The Mark 10 and Mark 11 were almost identical, differing only in the shape of their pattern and range. The Mark 10 fired an elliptical pattern measuring about 140 x 120 feet to a range of 200 yards. The Mark 11 fired a circular pattern measuring 200 feet in diameter out to a range of about 188 yards.

 

     

 

 British Flower Class Corvette/Action Class Patrol Gunboat.

 The Flower (rev.) class corvette   

While German wolfpacks ravaged Allied shipping, scientists and engineers on both sides of the Atlantic worked frantically to develop new ways to combat the U-boat.

Perhaps the most pivotal advances, and the best-kept secrets, came from Project Ultra at England's Bletchley Park. Naval codebreakers cracked the formidable German Enigma codes, which the Germans believed to be unbreakable. Aided by Britain's most gifted mathematicians and machines called "bombes" -- an early mechanical computer -- Ultra was deciphering German communications within 24 hours in the latter years of the war.

Another advance, also unknown to the Germans, was the High Frequency Direction Finder (HF/DF, or "huff duff"). The HF/DF was a system of shore-based and ship-based antennas that allowed the Allies to pinpoint a U-boat using the sub's own radio signal. Because wolfpack tactics depended heavily on coordinating attacks by radio, HF/DF allowed the convoys to evade the shadowing sub while the escort ships, using improved radar and sonar systems, zeroed in and attacked.

 

 

 

H.M.S. STATICE Stats (corvette).

Navy:	The Royal Navy
Type:	Corvette
Class:	Flower (reserve)
Penant:	K 281
Built by:	Collingwood Shipyards Ltd. (Collingwood, Ontario, Canada)
Ordered:
Laid down:
Launched:	10 Apr, 1943
Commissioned:
End service:
Specifications:  Displacement 980 t; Length 205'; Beam 33'; Draft 11'; Speed 16 kts; Complement 109; Armament one 4" gun mount, one 2-pounder gun mount, six 20mm, two dct, four dcp, one hedgehog dcp.
History:	Transferred to the Royal Navy under lend-lease. Returned to the United States Navy on 21 June 1946.
Former name:	Vinn (U.S. Navy).

 

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Original German Submarine Badge