Great game! Really cozy and lovely, and I like the morse code idea- it's so adorable how the boats just wait there until you communicate with them.
Would be great for mobile too!
The only small critique I have is the sound for the 'long' signal was a little grating, especially as the other sounds were quite nice. Found myself dealing with the ones who used the long signal first xD -- of course, that might have been their plan all along!
Could be cool to have boats only show their code when you hover the mouse over them too? Makes it even more interactive.