Sticking up in the middle of the busy Clyde shipping lanes, Ailsa Craig has seen its fair share of wrecks. Approaching the drop off point on the south west of the island the cliffs tower above us. The skipper puts the boat in neutral and we roll over the stern. We had comprehensive instructions of how to find the remains of three iron ships from the 1870s and 1880s. Follow the boulders down and out 'till they meet the seabed, then turn east.
As we get to the bottom of the boulder slope where it meets the flat gravel seabed the last terrace of boulders is free of kelp, giving the dead men's fingers and plumose anemones a chance to provide an unrestricted display of dazzling colour.
It is not long before the first scraps of wreckage appear. A few girders lying on top of the gravel, rusty looking but polished to clean iron in places where they had been scoured by heavy seas.
The first of the three wrecks, thought to be the 797-ton paddle steamer Duke of Edinburgh. On 18th January 1870 she steamed through fog at full speed into the rock, striking so hard that half the ship was out of the water. Subsequent salvage attempts recovered much of the cargo, but the ship was a total loss.
100 metres or so further eastwards we come to some more girders resting across the bottom of the boulder slope. This is the remains of the 1083-ton steamship Austria that hit the rocks on the night of 15th October 1884.
Now out of the lee of Ailsa Craig and heading into a gentle current, the marine life is both larger and more prolific. Armies of sea urchins are grazing on the rocks. Curious wrasse swim by to see what is happening. Pollack loiter in the current above the boulders.
Over 40 minutes into the dive and there is plenty of bottom time left, the maximum depth so far just 13 metres. It is probably another 200 metres before we come to the remains of the third wreck, the Pennon, a small 94-ton steamer.
This time the wreckage lies along the boulder slope. Iron plates and girders lie flat along the boulders, with occasional stray scraps of metal scattered to the gravel seabed. Again there is no sign of the machinery that was presumably salvaged.
We could have explored further, but after an hour in the water air was getting low, we were all feeling the cold, and I was long out of film.