Having a relatively comfortable place to rest your weary body at the end of your stint on the oars can make a massive difference to morale. Sure it’s not going to be as comfortable as a thick posture-pedic fully sprung king size bed but getting your bedding right can make all the difference to your comfort even if it is only 2″-3″ thick.
Firstly, consider what you’re going to be laying the mattress onto. If this isn’t a flat surface then the bumps and lumps of fittings such as hatch covers, belts and bolt or screwheads will prod you in uncomfortable places. So the first thing to do would be to stick some high density foam rubber (like a camping mat cut to fit) around the hatch covers and other fittings. In the image below, foam rubber has been stuck around the hatches that are mounted under the bed in the cabin to ensure the mattress is resting on a surface which is as level as possible but without adding much extra weight.
Remember than when it is wet outside (either through rain or waves) that you’re going to be coming back into the cabin wet. You’ll then need to get out of your foul weather gear before settling down to sleep. It also isn’t unheard of for waves to break over the cabin in stormy conditions or on the boat when you’re getting into the cabin letting water into the cabin and getting you bedding wet. If you use a usual type of mattress then the water will soak into it and after a few days will start to rot. Yuk! There are marine specialists who are able to make a thin foam based mattress in the perfect shape to suit your cabin and in a waterproof vinyl cover to help prevent rot.
Cabins of ocean row boats are generally not well ventilated and so either hot and sweaty (later in the journey) or cold and dripping with condensation (earlier in the trip). With the colder water temperatures of the North Pacific near the start line the temperature in general will be cold and crawling into a warm and dry sleeping bag will prove to be a real treat compared with just lying in whatever clothes you have taken with you. However, trying to keep anything dry will prove to be very difficult for the first few weeks. The weather will rarely be good enough to allow you to dry everything out and get rid of the moisture that has accumulated inside so be prepared and consider buying a sleeping bag that is easy to dry out and/or has a waterproof cover / bivvy bag on the outside to keep the bag nice and dry on the inside. But don’t forget to dry yourself off before you get inside otherwise it’ll just get gradually more soggy!