‘The most intact U-boat wreck I’ve ever seen’ U-Boat Hunter Dr Innes McCartney – The Discovery of U778

U-778. Photo: Dr Innes McCartney
U-778. Photo: Dr Innes McCartney

German submarine U-778 was a Type VIIC U-boat built for Nazi Germany’s Kriegsmarine in World War II. She only completed one combat patrol and sank no Allied ships. She was surrendered to the Allies at Bergen on the 8 May 1945.

On 4 December 1945, she was being towed offshore, to be scuttled as part of Operation Deadlight, but foundered and sank before reaching the scuttling ground, at a point 55°32′N 7°7′W, 16 nautical miles (30 km; 18 mi) North East of Malin Head in around 70 metres (230 ft) of water.

Throughout the Second World War, U-boats played a critical role in Germany’s warfare strategy. This was especially so during the Battle of the Atlantic, which lasted the whole length of the war.

The wreck was rediscovered by marine archaeologist Innes McCartney in 2001


This was the dive when I discovered the U-boat which is probably U778 on 22 July 2001. Again, visibility which is stunning as the bows of a U-boat appear ahead


Ripping current coming over the wreck meant i was crawling (literally) towards the wreck. Outer torpedo doors closed and intact – very rare (Innes McCartney).


The line links our shotline to the wreck. It was dragging in the current and we nearly missed the site entirely.  The entire U-boat looks band new! (Innes McCartney).


One of the reasons that Germany depended so much on submarines was that, as a result of the Treaty of Versailles, the number of marine craft they could have was limited. Restrictions put in place after the First World War prevented them from building up a strong navy.

Under the terms of the treaty they were only allowed to have six battleships of no more than 10,000 tons each, six cruisers and 12 destroyers. As U-boats were not specifically mentioned in the treaty, these became Germany’s way of gaining some advantage at sea.

The U-boat has the rare late-war GHG balcony – a passive/active sonar array (Innes McCartney)

The U-boats generally carried deck a gun in addition to its torpedoes. The gun could be used while on the surface, but it was the torpedo that was most associated with submarine warfare, and the main reason they were so feared by the enemies of Nazi Germany. Even Winston Churchill himself once admitted that the German U-boat was the only thing that he feared. The U-boats were very successful in their mission to disrupt the Allied shipping operations including disruption food supplies. Out of almost 3000 ships sunk by the U-boats, 2,845 were merchant ships. Less than 200 were battleships.


Aft deck pristine too (Innes McCartney).



Steel torpedo tube – sign of a late war U-boat (Innes McCartney).



Conning tower recedes as the current blasts me down the wreck (Innes McCartney).



Stunning conning tower as I drift back down the foredeck (Innes McCartney).



Al’s bottom line heads off into the distance downcurrent..tight as a bowstring.. Glad we planned to bag off at 30m!! (Innes McCartney).



The U-boat’s snorkel mast in the deck recess with hydraulic elevator piston behind (Innes McCartney).



The piston in front of the conning tower. Even the flange pipe which links to the snorkel when it is erected is still in place, along with the spray deflector (Innes McCartney).



Open mushroom air intake (Innes McCartney).



The Bridge is covered in a net, but inside all the bridge equipment is still where it should be – incredible! (Innes McCartney).



By the port side of the tower the snorkel flange (bottom) and collar (top) are still in place. I have never seen this before or since (Innes McCartney).


The base of the bridge shows the conning tower hatch is open and the main control pillar (left ) is still in place (Innes McCartney).


Another gratuitous shot of this incredibly intact U-boat wreck (Innes McCartney).


Foredeck largely intact with conning tower in distance. Greg crawling along the wreck towards me. by now the current was running really quickly (Innes McCartney).


(Innes McCartney).


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Dr. Innes McCartney – Nautical Archaeologist, Naval Historian and 26 years a Wreck Diver.

Innes McCartney

Innes McCartney is one of the authors writing for WAR HISTORY ONLINE