The Thesis was a 151nt general cargo iron steamship built by McIlwaine, Lewis & Co., Belfast and launched in 1887. Her dimensions were 167.0′ x 25.0′ x 11.7′.
Details of the loss of the Belfast steamship Thesis are very vague as contemporary reports are unusually brief and lack any explanation of her loss. She was en route from Middlesbrough to Belfast with a cargo of pig iron in October 1889.
She had sailed north round Scotland and, as she turned south, she presumably passed through the Minch before taking a route close to the mainland and through the Sound of Mull. As she reached the south end of the Sound, towards midnight on Tuesday 15th, the night was calm and apparently clear.
The Wreck Today
The wreck of the Thesis lies on a steeply sloping shingle seabed in position 56°29.933’N, 005°41.466’W (GPS) only fifty metres from the rocky shoreline. The bow points to the shore and lies in just over 20 metres while the stern lies in 35 metres with a depth of around 30 – 32 metres on the wreck at the stern. The wreck itself is basically only the hull of the ship as all superstructure and decking have disappeared. Many of the hull plates have also fallen away and lie scattered on the seabed on either side of the wreck. Unfortunately in recent years the wreck has been damaged by a scallop dredger and the bow section is no longer as impressive as it was.
The state of the wreck makes it possible to have a spectacular dive in the often excellent visibility. A diver can swim the entire length of the vessel below deck level with the many holes in the ship’s sides allowing light to penetrate inside the hull and the diver to peer out at the shoals of fish that patrol the wreck at all times. As you descend and manoeuvre round the boiler and the remains of the engines, shafts of light pierce the darkness through empty portholes. Emerging into the stern hold and then on down towards stern itself the light fades slightly but generally is still good even on the seabed at 35 metres beneath the back end of the ship.
The Sound of Mull is well known for its strong currents and the wreck of the Thesis is probably the most affected as the tides whips round the headland at Rubha an Ridire. At some states of the tide the wreck will be undiveable and even when the current drops or at slack water it is still recommended for the experienced only as it can turn from slack to a strong run in the time it takes to complete a dive. When the tide is strong the dive described above is the only one possible as otherwise the diver is liable to be swept off the wreck or at least will spend an uncomfortable time clinging to the wreck to avoid being swept away.