Mostly physical labor. Seriously. People think we just sit around drinking beer and playing around, but that isn't real life on a boat. On a boat you can't just open a cupboard and take out a can of soup, you have to move at least 5 to 6 things to get to the place where the can is stored. Multiply that by 10 if you are working on repairing something. Imagine our boat as a 30 foot hallway with an engine, kitchen, living room, bathroom, bedroom, and a spare room (for navigation). In this space you have to store food and water for 2-3 months, spare parts for everything, 5 different sails, survival gear (life-raft, survival suits, spare radios, spare GPS, emergency watermaker, etc.), about a mile of ropes and chain, tools for fixing anything, books, charts, navigation equipment, clothes ranging from suits to sub-artic foul weather gear, dishes, pots and pans, blankets, spare anchors and lots of odds and ends. The sum total of this gear weighs, according to the travel lift scale, 3,000+ pounds. Every nook and cranny contains something. Everything fits somewhere and you end up carrying a mental map of the boat with you to save from having to move 40 things to search for certain size wrench.
You have to cook 3 meals a day, everyday. You have to maintain the engine, rigging, ropes, hardware, polish, clean, cook, keep a constant watch on the weather, carefully monitor your fresh water supply, do laundry by hand in a bucket, wash dishes by hand, clean the boat bottom, maintain the outboard, the list goes on. There is time set aside, for sweating, swimming to cool off, hiking, meeting people, snorkeling and reading, but there is never a lack of work.
When you arrive in port, you have to carry all your provisions, sometimes miles. This often includes water and fuel, which are extremely heavy. You have to scour the town for elusive items of hardware, food or generic everyday things like sponges. And you have to carry everything. An ENTIRE day, and 10 miles of walking, can be taken up just trying to find a certain bolt or a piece of plywood. If you're lucky, you find it.
There's still stress too. If we are in a nice protected port, we can at least let our guard down about the weather and breath a sigh of relief, but most of the time the specter of bad weather hangs over us. It is impossible to explain to people who are inexperienced in living outside how the weather effects you. Within a timeframe of six hours a good day can turn very very bad, so we have to constantly be aware of the environment to avoid trouble.
So to the casual observer it appears like laid-back lazy lifestyle, but delve a little deeper and you'll see much more work goes into getting a sailboat safely from Point A to Point B.