Qualla: SM UC-42

SM UC-42: Introduction

Sat, 23 May 2026 00:00:00 GMT

She was a small submarine with a small purpose. UC-42 carried eighteen mines, three torpedo tubes, an 8.8 cm deck gun and a crew of 26 - the kind of compact minelayer the Imperial German Navy built dozens of in 1916 to choke the British shipping lanes. Her last patrol began in Belgium on 1 September 1917. Some time between then and 31 October, while planting mines outside the entrance to Cork Harbour, one of her own mines detonated under her stern. She sank with all hands. The wreck stayed hidden for 93 years. In 2010 Irish divers found her sitting upright in 27 metres of water off Roche's Point, identified her by the serial number stamped on a propeller, and pinned a bronze plaque to her stern declaring her a war grave.

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SM UC-42: Type UC II

Sat, 23 May 2026 00:00:00 GMT

UC-42 was a Type UC II coastal minelayer, the most numerous German U-boat class of the First World War. The figures are tight and economical: 49.45 metres long, 5.22 metres wide, displacement of 400 tons on the surface and 480 submerged. Two six-cylinder four-stroke diesels gave ...

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SM UC-42: Six Patrols, Fourteen Ships

Sat, 23 May 2026 00:00:00 GMT

From 1 January 1917 onwards, UC-42 made six patrols from German-occupied Belgian ports. In total she sank fourteen merchant vessels totaling 9,877 gross register tons, and disabled a warship of 1,210 tons displacement. These were the numbers of the unrestricted submarine warfare ...

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SM UC-42: An Oil Slick, Some Bubbles

Sat, 23 May 2026 00:00:00 GMT

On 31 October 1917 the British torpedo boat TB 055 was escorting minesweepers at the entrance to Cork Harbour - the place we now call Roche's Point. At 1500 hours a crew member spotted an oil track on the water. TB 055 followed it, dropped a hydrophone, and heard 'hammering' and ...

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SM UC-42: The Mystery in the Logs

Sat, 23 May 2026 00:00:00 GMT

There is a quiet puzzle in the British Admiralty file. UC-42 had left Belgium on 1 September. The longest known cruise for a UC boat in home waters was 24 days. By 31 October, when TB 055 dropped its depth charge, UC-42 must already have been dead for weeks. So what were the 'ham...

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SM UC-42: Rediscovery and Respect

Sat, 23 May 2026 00:00:00 GMT

The wreck was rediscovered on 6 November 2010 by Irish divers Ian Kelleher, Niall O'Regan, Philip Johnston, Eoin McGarry and Timmy Carey, in 27 metres of water off Roche's Point. The hull showed 'little obvious explosive damage' - inconsistent with a depth charge, consistent with...

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