So much of the popular press and media seems to associate boating with one of two "extremes". You are either a full-up passagemaker, going across the open seas, visiting far lands and rounding Cape Horn. At the other end of the spectrum, you are a weekend runabout operator towing the kids on a ring or skiing. Mind you, I don’t think there is anything wrong with either end if that’s your thing (and you have the means), but there is a "middle ground" that seems very attractive to me that doesn’t get as much following.
There are many names for this… river cruising, coastal cruising, gunk holing, etc. all probably encompass some of the ideas. But just in the U.S. there are thousands of miles of navigable rivers (open to fairly large craft) that are often ignored. Did you know that you can get to Oklahoma from the ocean? I didn’t until a couple of years ago.
Much of Europe is accessible by canal, providing your craft will fit… and many of the canals will handle some pretty large craft. Great Britain is somewhat an exception to this. They have a tremendous number of canals, but many are designed around a "narrowboat"… a long, very narrow (7′ or so) craft that is pretty unique to them. But even the U.K. has quite a few larger waterways.
Studying history we know that cities grew up around transportation methods, and a couple of hundred years ago, that meant rivers. So many of the worlds large cities are accessible by water.
You can make years long trips via water and never cross an ocean. You could probably do it without getting near the ocean 🙂 The Great Loop (circumnavigating the eastern United States of America) is one example. For much of the trip you are in protected, inland waters.
I want to expand on some of the on-line resources I have found for inland travel. There are publically accessible charts for the U.S. now, and several cruising guides you can purchase.