It might be hard to believe, but I highly recommend going to full winter gear
for the North Atlantic route
. That to me means Patagonia or other high-tech backpacking type polyester long underwear (don't cheap out), tops and bottoms, full heavy Polartec fleece uppers and bottoms (heavyweight), Merino wool socks, a ski hat lined with Polartec and wool on the outside, heavy gloves and/or mittens and multiple pairs because they will get wet. I like polar fleece with the windblocking feature for gloves, but on a hard night sometimes leather ski gloves are better for the grip. Duluth Trading makes some good waterproof and warm fleece lined work gloves that also have rubbery gripping areas. Skip anything cotton because it doesn't keep you warm when it gets wet. Go the backpacking route for warm gear
and then have heavy foul weather gear
and heavy boots over. I've needed all this stuff for offshore
as far south as between Bermuda
and St. Thomas, and north of Bermuda
even in the summer is much, much colder. Absolutely bring a SS thermos for hot middle of the night beverages.