27 crew lost their lives when a German U-Boat sank in Cork Harbour in 1917. It is believed that the submarine had been laying mines and attacking British vessels when it exploded and sank.

Up to now, historians believed it had been demolished by the British two years later.

The discovery was made by a team of five amateur scuba-divers near Roches Point in Cork Harbour in November 2010. Ian Kelleher, Niall O’Regan, Philip Johnston, Eoin McGarry and Timmy Carey had been searching for traces of the wreck for over a year. To their surprise the vessel was in good condition when they finally found it. The ship's number was found stamped in a propellor confirming that it was in fact the German U-Boat 'UC-42'.

Describing the discovery as "a poignant moment", diver Ian Kelleher says

We placed the plaque to commemorate the crew. The fact that they were entombed in something so small. It's quite hard to imagine unless you see it personally.

An RTÉ News report by Jennie O Sullivan broadcast on 24 January 2011.