I read recently about divers doing risky dives at Dorothea Quarry and elsewhere with only one cylinder and DV, and that this was silly, as they should really have a spare air source.
     The safest set-up, it was suggested, was a main cylinder with independent pony and regulator, though more and more people these days seem to use twinsets with separate DVs.
     Only one woman in our club uses a twinset, though some use ponies for trips to places like Scapa. A few heavy-breathing men use ponies in addition to their 15 litres, but having asked around it seems that a lot of women find the pony-bottle combination hard to lift and carry. Some prefer to dive only with 10 litre tanks because of the weight.
     By my second season, more than 12 years ago, I had used a pony once or twice, but being only 5ft 3in found it cumbersome and awkward when surface-swimming.
     It was well into September and we decided to have one last dive on the Lucy in west Wales before the season ended.
     The Lucy is a cracking dive but the wreck sits upright in roughly 40m and is not ideal for diving from a hard boat if a current is running. I had made the journey out through Jack Sound at least half a dozen times, but had only been able to dive it once before.
     I had heard marvellous tales of getting into the engine room and swimming through a cabin on deck and was really up for it. So there we were, diving off our club's new RIB.
     Neither my buddy Janet nor I had a computer in those days. We sat in the boat with our tables, calculating carefully. We would have about 8 minutes' bottom time if we went to 40m, but if the deck looked interesting we would do that, get inside the cabin and penetrate the wreck.
     This would give us slightly longer, but a key point was a deco stop at 6m for at least two minutes. We both had 12 litre cylinders and, unusually, 3 litre ponies.
     Janet was the ideal buddy, laid-back and such a light breather that she usually came back with half a tankful. She was also big and a regular weight-lifter, so ponies posed no problems for her! We had one big, powerful torch each. I shudder to think of it now, as I never dive without two spares, and usually a strobe as well.
     We set off down the line in high spirits. It looked pretty rough and dark but we weren't worried. We had planned the dive and were all set to dive the plan.
     Someone had rigged a buoy to the stern of the wreck as well as the bow. We went down the line and once we hit the side of the Lucy set off towards the bows. The visibility was atrocious - around 6in with our best torch.
     We tried to hold on to each other, but were knocked in and out of the wreck by the current. Then I was pulled right over by the unaccustomed combined weight of my pony cylinder hitched to the side of my 12 litre. Ending up like a beached turtle, I lost Janet and her torch.
     Our contingency plan if we lost each other was to work our way back to the line and ascend, but when I finally righted myself I had no idea where I was.
     Had I fallen inside the wreck and, flailing around, ended up in the cabin? The weight of the pony bottle kept pulling me over, and as I thrashed around trying to get my balance, I destroyed the tiny amount of viz that had remained.
     I did a very clumsy 360¡ searching for Janet and her torch. Then, to my horror I realised that my torch was fading. All that crashing around must have loosened the seal and it was gradually filling up. What little light I had didn't penetrate far.
     I still didn't know whether I was inside the Lucy, on deck or even the right way up. I finally brought the dwindling torch beam to bear on my gauges - 41m! All that flailing had put me on the seabed, off the wreck, deeper than I had ever been before and alone!
     Yes, I had the security of my pony and valve. No, I was petrified. I had to ascend without a line, in the dark and on my own.
     I took a deep breath, stood up and, to my immense relief, felt the reassuring bulk of the Lucy behind me. So I made my way up the side of the wreck and inched along the side, far too scared to swap my main DV for the one on my pony, and praying that the 12 litre would last at least until the deco stop when I hit the line.
     I made a classic ascent in the dark, timing it carefully with my luminous dive watch, my torch now drowned. I even stopped at 6m for two minutes, and when I broke the water I gasped out: "I've lost Janet. I fell off the wreck and ended on the bottom and my torch flooded!"
     "Look behind you," they said, and there on the line were Janet's bubbles as she did her stop. "We've been following your bubbles and you've been about 30 seconds away from each other all dive.
     "By the way, did you realise that you went down the stern line together and both came up the bow line?"
     I sold my pony after that. I didn't feel I could risk being toppled over again!