The 378 ton Thesis was 167ft long with a beam of 25ft, and drew nearly 18ft. In early October, 1889, she left Middlesbrough carrying a cargo of pig-iron for her home port of Belfast. She went north around the tip of Scotland and, to avoid the stormy waters of the Tiree Passage, took the often calmer short cut through the Sound of Mull. The charted position for the Thesis is 56 30.03N, 5 41.43W Depth: 25m
In thick fog, just after midnight on 16 October, 1889, the Thesis ran onto a reef just off the eastern shore of the southern end of the Sound. There was no doubt that she was badly damaged and Captain Wallace ordered everyone into the boats. It was a wise move. It was not long before his ship slid off the reef and sank in deep water.
Removed hull plates allow lots of light inside and make wreck penetration easy. The Thesis suffered storm damage over the winter of 2014-2015. The bow section has collapsed and there is further damage near the stern. She is still a great dive though. Sheltered from all but the worst weather. Usually excellent visibility. Strong tides. Launch: Oban, Lochaline.