the water is the best teacher
In a safe setting get into the water repeated times over 30min with your get-up and see where the weak links are,if your core is good but your hands are numb, you’re screwed, if your body and hands are warm but your head is bare you could be watching the horizon do flips as vestibular function is whacked from cold water in the ears. I’ve seen that one happen to a big strong person and it turned them into a stumbling drunk for five minutes.
In sub 50degrees I stretched the farmer john/dry top outfit with a 3mm neoprene vest with lycra short sleeves, It gave me 6mm on my chest but the coated lycra sleeves and poly pro top was inadequate for the arms for long. After five minutes of immersed thrashing water eventually makes it’s way up through the hollow of your back and there’s a pint in either sleeve, held by the latex gasket.
I could handle a few minutes of bare hands IF my entire body was pumping heat vigorously but if not regaining heat in hands was nearly a lost cause. Keeping neoprene gloves stuffed between pfd and chest kept them warm when needed.
Fuzzy rubber or similar hood material can make a big difference for that initial shock, immersion longer than a few minutes and recovery from heat loss.
Been there
I learned to wear earplugs the hard way when I first learned to roll. I was plenty warm, but the cold water rushing into my ears got me so disoriented that I barely made it back to shore, and that was only 50 feet away.
I was nauseous as well. Probably the closest I’ve ever been to true vertigo, and the closest I ever want to get to it, too.
saw it
ACA IDW, water just below 50 and air just above, we were in a protected bay going through a videotaped exercise where each person has basic strokes and rolls videotaped. Camera is on the dock, paddler is in 7’ of water about 30’ from shore. I offer to loan him a hood and he says “I’m fine”,ww.paddler with lots of muscle and heat generating capacity. He does one roll, fine, second roll, fine, third roll not from set-up and does fine,then attempts a hand roll with about four failed attemps then wet-exits. Total immersion time of head maybe 30seconds over a couple minutes. When he wet-exited he swam/towed his boat to shore and proceeded to stumble/crash up the embankment to the dock house. He looked drunk going up the hill, said it took him 15minutes to get squared away before coming down and finishing the next few hours of class. Said he never warmed up until after lunch.
I don’t have one. Seriously.
How many people do?
Can’t beat this advice
Cold water
I took a rough water course last December, in Hood River. When we did our all-in drill that snowy day, I was wearing a drysuit with long underwear and good gloves, but nothing useful on my head. I was highly motivated to be the first back in my boat. Now, whenever the water is seriously cold I wear my neoprene hood. It is not just a beanie, it goes low in back and under my chin. I also go under water every paddling day, so that I know I am ready if need be.
Everyone, if you are not willing and ready to fully immerse, please be considerate of your family, friends and life insurance company, keep your boat dry until the water warms up.
hoods
have you tried the fuzzy rubber/poly hood combos? It’s not the same insulation as 3-5mm hood for continual immersion but it works better for continual wear with with occasional immersion. You’re right about covering the neck for keeping heat in. My experience is that the neoprene hood is too hot when not wet, can’t hear through and can allow cold flushing when my head is at extreme movements. The combo of a divers hood liner and thin fuzzy rubber or NRS thin neoprene/Mystery fabric makes for a layerable combo you can hear through but slows down the flow of water into the ears better. The water still gets in but there’s no quick flushing as gaps open up while upside down and rolling.
Bibs Can Work Well
I've used a drytop/bib combo for 7 years (Bomber Gear top, Kokatat bib). The top is breathable (that's where I sweat the most) but I was able to save a ton of money by getting a non-breathable bib. I wear two wicking layers under the bib to manage moisture: thin Powerstretch next to the skin and a thick Polartec 300 outer layer. The moisture migrates out to the outer layer and my skin stays dry.
The key to waterproofness is after you mate the drytop and bib aprons carefully (have someone roll the back while you roll the front), THEN wear a sprayskirt with a tight neoprene tunnel over the roll.
My bib came with ankle gaskets and last year for the first time I could not warm my feet up if they got wet (must be part of the aging process). This year I cut off the gaskets and installed latex booties and what a difference! My knee-high Chotas can be full of water but my dry feet stay warm. That is the reason for drysuits. Dry=warm.
By the way, I religiously use 303 on my latex gaskets and am still using the original wrist and neck gaskets on my 7-year-old drytop.
Neoprene waders
Down here a lot of the kayak fishermen wear neoprene waders in winter. Usually with a rain jacket on top. Frogg Toggs, which seem like just tyvek, are really popular. Would be better if they wore drytops, but these guys are fishing on stable SOTs in shallow water, so I guess the risk is low. Of course, most here in Texas are too macho to wear PFDs (when challenged, they claim they will put them on if they are going to cross deep water - yeah, right) so if they are in water over their head they are going to get really wet, really cold, and not be very buoyant.