In reply to talbot_60:
Tragic. All the best to the family and friends affected.
It sounds very much to me like "cold water shock", consistent with loss of muscular ability described with the ladders, failure to swim what sounds like a short distance, and the otherwise lack of obvious cause of death other than drowning in calm sea.
I don't say this for the sake of speculation, but just in the hope that other Deep Water Soloers are aware of this possibility. Having dropped a set of wires into the sea while climbing a route on the Aberdeen sea cliffs, I thought I could see them caught on some weed a couple of metres below the surface. Being a pretty confident swimmer, I finished the route, and then stripped off and jumped in to the sea. I swam over to where I thought the wires were, and felt my lungs were very tight, and that I couldn't get a full breath, I duck dived once and spotted the wires, but couldn't reach them, when I came back up I couldn't get a breath, tried to relax and the breath came back, I tried again, and same thing. I started to feel really tired, and thought I'd have one last go. I got the wires, and when I came up couldn't really breath properly, I found my limbs wouldn't do what I really wanted them to, and ended up skirting along the edge of the cliff until I reached an easy low rock I could get onto, which was pretty difficult. I felt very weird and slightly dizzy for a good hour after that. This despite the fact that I often go swimming with no wet suit in North Uist throughout the year, something of a tradition in our family! It was really quite warm outside, and the sea, prob 8-9degC given the time of year. I got my wires, but it was alot more risky a retrieval than I was expecting. Two things were going on, I think, one was the "diving response", and the forthcoming weakness and limb inability along with subsequent dizziness was probably due to the "cold water shock" response.
http://www.chronicbackpainclinic.com/pdf/cold_water_shock.pdf