I've noticed the chill-loss phenomena with breathhold too.
When I dive without a suit the quickest way to lose the chill is to get down. Even today in my suit, if I started to feel chilled I'd just breath up and dive.
Today I took my current fav piece of kit - my henderson ice mask, out for a longer swim. There are some cooling pipes from the old power plant that end about 1/4-1/3 mile out in the bay in 35 feet of water. In the summer it's really dangerous due to idiot boaters - divers flag or no. This is the first time I've ever seen them. The site is popular with scubies because it takes them about a tank there and back - they do alot of certification dives and stuff. The pipes end in big cribs containing rocks to diffused the heat (before the plant was torn down). I tried my Cressi matrix with the mask this time - it was a great, long swim - good vis despite the overcast but still no fish
a disheartening number of beer cans and coffee cups - I'm sure the large pipes act as a sort of catchall for crap that gets thrown off boats. I'll have to check with the local scuba guys and see if maybe they want to do a spring cleanup.
