SS Thesis

Underwater archaeology on the SS Thesis

A diver swimming through one of the holds of the Thesis. Photo Simon Volpe The WreckMAP and SOMAP projects undertaken by NAS Scotland allow keen amateur underwater archaeologists to get to grips with some of the most exciting underwater sites in Britain! To get involved you should be an experienced diver, and have undertaken the NAS part I qualification in underwater archaeology – see NAS Scotland page for details.

The Thesis was an iron built cargo vessel constructed in Belfast by McIlwain, Lewis and Co. and launched in January 1887. Some of her forward hull plating was probably lost in the original wrecking incident in 1889, but more plates have fallen away from her ribs since that date. The loss of large sections of her iron skin allows light to stream into the vessel, and gives the wreck a magical quality.
Soft corals established on the aft winch. Photo Hazel Veitch.

Soft corals photographed on the Thesis by Hazel Veitch.The site is subject to strong currents that have encouraged colonisation by a range of filter feeders. Over the years the outline of the wreck has been softened by a heavy encrustation of marine life, which includes sea-firs and soft corals. The Thesis today also acts as a sheltered haven for fish, including wrasse and conger eels. It is, therefore, no surprise that she is one of the most atmospheric dive sites in British waters, and consistently listed amongst the top ten British wreck dives.

One of the most popular dive sites in the UK

A diver leaving the hold over the high coaming, note the loss of sealife on the lip of the coaming where it has been abraded by passing divers. Photo Simon Volpe Her popularity as a dive site makes the Thesis important to the local economy, and as no examples of this type of vessel remain, she is now also a site of some cultural and historic interest. As a consequence it is a matter of some importance to learn more about the wreck. The establishment of the deck plan (shown in the animation above) is one important step that permits us to:

Learn more about her construction, which is of historic interest as none of the original plans or photographs have been located.
Accurately describe the current condition of the wreck, and so monitor her deterioration.
Plan biological and other assays, which will allow us to evaluate the site in some detail, and provide general insights into site formation processes.

Additional surveys were carried out planning the remaining hull plates on the forward section of the ship. These plans will allow us to monitor the loss of plating, and allow us to quantify the rate of deterioration of the vessel.


Philip Robertson, who organised SOMAP for many years.
The plan shown was developed over the last three years by visiting divers on the SOMAP and WreckMAP projects.
Photographs copyright Simon Volpe and Hazel Veitch 2002, by kind permission. Text and animation copyright SOMAP 2002.

The Thesis was investigated as part of the Sound of Mull Archaeological Project course for many years. This course is still run every summer by the dive centre; see our NAS Scotland link for further details.