The steel motor vessel Ballista was launched from the Northwich yard of W J Yarwood and Sons (Yard No 638) on 6th October 1939. She measured 95.0′ x 19.0′ x 7.9′ and her tonnage was 123 gross tons. She was powered by an EMX6 diesel engine by H. Widdop and Co Ltd., Keighly delivering 180 brake horse power. She was built for the Royal Fleet Auxiliary and operated in various roles for the Royal Navy throughout the war in in the post war years. In 1962 she was converted for operations as a torpedo recovery vessel before she was purchased by Elliot Diving Co Ltd, Helensburgh in April 1971 and registered in Glasgow.
The unusual story of the wreck of the Ballista saw the would be salvage vessel herself become the victim of a shipwreck. She was engaged in the salvage of coal from a ship, reputedly called the River Tay although the authors have not been able to trace any wreck of this name in the area, sunk on Eilean Rubha an Ridire in the Sound of Mull in the late 1940’s.
The Ballista was anchored near this small island, which lies at the east end of the Sound of Mull, on the night of 5/6th February, 1973. During the night a severe gale with 70 mph winds swept across Scotland causing the stern mooring of the Ballista to snap and, despite the efforts of her crew to keep her off using the ship’s engines, she came ashore right on top of the wreck the divers had been salvaging the day before. The three men aboard only managed to make a mad dash for the ship’s boat and escape before she hit the rocks and sank. They drifted ashore and had to spend an uncomfortable night on the barren island sheltering beneath their dinghy. They signalled with a torch to a number of passing ships during the night but it was morning before their luck changed. In the early light of dawn they spotted some distress flares washed ashore from their ship and using these easily attracted the attention of the passing car ferry Bute, whose officers raised the alarm. The men were picked up shortly after by the Burghead fishing boat Eminent and taken to Oban.
The wreck of the Ballista was visible above water for many years on the westerly point of Eilean Rubha an Ridire but in recent years has gradually disappeared beneath the surface. Some parts of her superstructure probably still appear above the surface at low tide. The wreck lies in position 56° 30.156’N, 005° 42.049’W (WGS84) and makes a pleasant shallow dive as a diversion from the deeper, more challenging wrecks of the Sound. She lies upright in depths of 3 – 10 metres.
Beneath her keel the remains of the previous wreck that attracted her owners to the site are also still visible. The hull of the Ballista is still reasonably in tact but otherwise she is merely a shell, patrolled by curious wrasse and pollock and shrouded in heavy kelp. The site is sheltered from the usual strong currents of the Sound of Mull but venture a few metres from her stern and the current can catch the unwary and sweep them out into the main channel.