U-Boat SM UB-55 (1918)
SM UB-55 wreck dive
The SM UB-55 wreck dive explores a German Type UB III submarine lost in the Dover Barrage in 1918. UB-55 left Zeebrugge for another patrol, then struck a mine while trying to pass through the Strait of Dover. As a result, 30 men died and 6 survived.
This SM UB-55 wreck dive gives you a serious late-war U-boat story with a direct Kent coast connection. By April 1918, the Dover Barrage had become a deadly barrier of mines, patrol vessels and detection systems. Therefore, any Flanders U-boat trying to reach open water faced a very dangerous passage.
SM UB-55 wreck dive: the submarine before the loss
A.G. Weser built UB-55 at Bremen as yard number 267. Germany ordered her on 20 May 1916, laid her down on 5 September 1916 and commissioned her on 1 July 1917. Kapitänleutnant Ralph Wenninger commanded her throughout her active career.
UB-55 belonged to the Type UB III class. These submarines gave Germany a more capable seagoing attack boat than the earlier coastal UB types. In addition, they carried torpedoes and an 8.8 cm deck gun, which allowed them to attack merchant shipping across wider patrol areas.
She joined the Flandern Flotilla in August 1917. From the Belgian coast, boats like UB-55 threatened Allied shipping in the Channel, the southern North Sea and the Atlantic approaches. Consequently, the Dover Strait became both a route out and a trap on the way through.
The Dover Barrage mine loss
On 22 April 1918, UB-55 tried to pass through the Dover Barrage while outbound from Zeebrugge. Uboat.net records that she sank at 51°01’N, 1°20’E after striking a mine. Thirty men died, while six survived.
Historic England records a detailed survivor-based account. UB-55 approached the minefield on the surface, then dived at about 4 am. Soon afterwards, the crew heard cables scraping along the hull, followed by an explosion that flooded the aft section and forced the submarine to the bottom.
At least some of the crew escaped through the forward and conning tower hatches as water rose inside the boat. Drifters later picked up six survivors and one body. Therefore, the wreck was not a mystery loss: the survivors confirmed the submarine as UB-55.
The casualty figures vary slightly in older records. However, the clearest working figure for this event page is 30 dead and 6 survivors. That keeps the story readable without turning the page into an argument over archival arithmetic, which is how joy goes to die.
You can read the vessel record in Uboat.net’s UB-55 entry. Meanwhile, Historic England records the loss, wreck identification and later archaeological notes in Historic England’s UB-55 wreck record.
The wreck today
For divers, UB-55 offers a compact but powerful Dover Strait submarine wreck. Survey records place the wreck about 10 km south of Dover, with the site lying upright in around 30 m of water. In addition, Historic England records that the pressure hull lies open just aft of the conning tower.
Royal Navy divers located and identified the wreck during the war. They recovered the 8.8 cm deck gun and sent material to London. Later records also note recovered small artefacts, although modern divers should treat the site with restraint and respect.
I would treat UB-55 as a war grave in practical and moral terms. However, I would not describe her as a current Protected Place under the Protection of Military Remains Act 1986 unless separate legal evidence confirms that status. Either way, this is a look, learn and leave-alone wreck.
The dive tells a sharp story: a successful U-boat, a mined barrier, six survivors and thirty men left inside the consequences. Finally, UB-55 reminds us that the Dover Barrage did not merely defend a coastline. It turned the Strait into a killing ground for submarines trying to pass through.
UB-55 also has a remarkable postscript. Her commander, Ralph Wenninger, survived the sinking and later joined the Luftwaffe, eventually rising to the rank of General der Flieger during the Second World War.
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