There is something special about a trilogy. The Lord of the Rings would both have been nothing if it had ended after part II, and three books creates a nice structure, a trinity of beginning, middle and an end.
But for some series its a book too far. The wonderfully brooding gothic Gormenghast trilogy is really two books and a rather long epilogue that I'd recommend that readers avoid. It would have been much better to have ended one book earlier.
I sort of got that feeling about Comfortable Cruising. Yes its a great description of sailing, a resource useful to anyone on either the East or West coasts of the Americas, in particular North of the Panama Canal.
But it felt too much like someone else's really good holiday stories. I enjoyed the two part round the world but this time the travel from Canada (West coast, sounds beautiful) to Canada (East coast, ditto) did not grip me, and the excessive exclamation marks became noticeable. Maybe I'm being a little harsh, as it seemed all in all far too pleasant a time from one who is stuck in London when its cold and wet.
If you're sailing these waters then by all means buy it.
But if you want a book just as a read, to experience second hand the adventure of round the world cruising, then I'd suggest the previous two, Just Cruising and Still Cruising.