Until you figure out a way to grow stuff on your boat that you can eat. Catching fish will only give you a limited diet. You can grow sprouts easily, but when you want bigger stuff like potatoes, onions and tomatoes, well ya pretty much need soil.

Of course if you harvest seaweed, that too can supplement your fish diet, but eventually you'll crave rice for your sushi.

And even Chichester had a pretty stout supply of wine and beer...