Here's what I learned from kayaking: Don't just dress for the water temperature, dress for immersion in the water, and test it. I used to kayak with a farmer john wetsuit and a drytop over that. With probably light fleece under the drytop. It worked fine for rolling practice, as long as the neoprene sprayskirt stayed on. Did lots of surf kayaking like that, I and used to get knocked down by the wave at the finish of each run, until I learned a bit more boat control. So I was rolling a lot, which means I now have a good roll... But I digress. One time, my buddy and I took a trip to the Pacific NW, and went sea kayking with a friend out a river and onto the Pacific. We were wearing our usual farmer johns and drytops, but coming back in, trying to ride the backs of the breaking waves at the mouth of the river, my buddy got knocked over, and couldn't get rolled up. Combo of buoyancy of PFD and unfamiliar boat. He wound up pulling the skirt and swimming in for 45 minutes, in typical June Pacific Ocean temps. Not sure how cold, but probably no higher than, what, 50º? He was very chilled to the bone, shivering and exhausted when he made shore. The problem of course is that the drytop filled from below, right up through the neoprene spray skirt, and he was completely immersed.
I have a dry suit, and went sailing the Force 5 on the lake on Black Friday last fall. Water was chilly, and it was breezy. Probably not the best time to shakedown cruise a new, small, performance sailboat. I got tons of spray on me (gosh, it's a wet boat) and of course I pulled a crappy gybe and went for a swim. Slid off the back deck down into the water on the leeward side, and swam around as quick as I could to get on the daggerboard before it had a chance to turtle. I got the boat upright quickly, and swam aboard. All I can tell you is that I didn't feel the water temperature at all, probably because of the adrenaline of necessity for righting the boat before turtle, so I probably forgot how the water felt at the time
My advice, if you're in a non-ballasted boat that is likely to leave you in the water (which the Snipe classifies, as does my GP14, or even a Thistle,) wear gear appropriate to the water temp and immersion. While salopettes and a smock qualify for water temps and copious spray, they wouldn't qualify for immersion. Keelboats are probably fine for salopettes and smocks. (Was breezy last weekend, and our RC chase boat dealt with a capsized Thistle and a capsized and swamped recreational kayak.)
I'm not sure what the water temps at the lake are like yet, it's been quite cold and rainy for a couple weeks around here. Not sure if I'd sail the Force 5 with wetsuit and long sleeved neoprene shirt quite yet, or keep it drysuit until it gets sunny for a few weeks. 'Cos I haven't been able to sail yet!
