This is just...gorgeous.  The writing is incredible -- your fantastical solar-sail ship feels familiar, while the places you sail to evoke that thrill of wonder and alienness even though to the player, everything should be equally strange.  Playwise, it's a bit of a "hoist sails and find out what happens" interface rather than letting you affect the plot much, but that works perfectly with the premise: you're an explorer just seeing what's out there.  This is a game to play for the storytelling rather than the challenge.  The puzzles are clever but not particularly difficult and the parser will accept both a wide variety of authentic nautical terms and more landlubber-friendly versions.  If you sail, this will be particularly enjoyable, but if you don't you won't be lost at all.  
 
It's mostly a story of pure exploration, but the ending is crisply wistful and satisfying.  It has a bit of a Ray Bradbury feel to it -- the nostalgic stories, not the creepy ones. 
 
The only problem I had was that in one situation, I tried multiple ways to get out of a trap, only to find myself suddenly free without doing anything different that I could see.  I'm not sure if that was a bug or me doing something slightly different without realizing.