The Topaz was a small ‘puffer type’ iron steamship built by Archibald McMillan & Son, Dumbarton (Yard No. 134) and launched in September 1866. She was sized to navigate the canals around Glasgow and her dimensions were 64.8′ x 16.8′ x 6.7′. She was powered by a small 2 cylinder steam engine generating 16 nominal horse power which was installed in 1877.
The Topaz left Kirkintilloch on 10th June 1880 en route to Belfast with a cargo of coal, under the command of her master Archibald McDougall, with a crew of three onboard. The following day the Topaz had reached the outer Firth of Clyde punching into a stiff SSW F5 breeze. When about 10miles south east of the Sanda Island there was a large report as her boiler exploded, throwing her master into the sea. He was not seen again. The remaining three crew managed to scramble into the ship’s boat and made their escape shortly before the Topaz sank in deep water.
The crew drifted with the tide off Sanda until a passing steamlighter, the SS Glasgow, rendered assistance by taking them aboard and eventually landed the survivors ashore in Belfast.
The wreck of the Topaz lies in position 55°12.383’N 005°22.265’W. The hydrographic survey report for this mark suggests a wreck of 50 metres in length. However, on diving the mark it became clear that it was the remains of a small puffer with a cargo of coal. The wreck lies 130/310° with stern towards Sanda Island. The wreck rises no more than 1-1.5 metres above the surrounding seabed. The highest part is around the engine room at the stern. The wreck has been absorbed by the soft sand and silt and is only and outline in the seabed. Within the wreck there is more to see and explore. The wreck is tidal.