Once I forgot to take shoes to Silvaplana (1800 meter above the see level) and the water was extremely cold (I guess 11-12 deg. C). It was only possible to sail in 30 minutes intervals and than I had to go out and warm up my feet.
But comfortable is it definetely not and I would not recommend it!
PA 86 & eVo 100 (with S-1); iS 101 & 122 & 144 (with Overdrive)