If I may suggest an improvement, if you desire more than the smallest of audiences, you may want to enlist help from someone with more user interface or design experience. As is, even this extremely geeky and intellectually curious HN audience is struggling just to get the simplest race started. I finally got my boat started after quite a lot of clicking and fiddling -- these were the most confusing steps if it helps:
1. Figuring out what exactly the site does. The help page really helped, but it took me a while to realize it existed. I'd suggest adding more help content to the home page.
2. Passing the captcha took me a bit of Googling - this is unnecessary friction if you want a broader audience.
3. Once I started a race, it was very confusing that I had to just wait a minute and continually refresh the page before I could even enter the heading for my boat to use.
4. It's weird that the maps aren't on the same page as where I enter my boat's heading. It's also unwieldy to refresh all of these pages constantly - a continually updated page would be a natural improvement.
5. After entering a heading and pressing "Change course!", I expected my boat to start moving. It took me several minutes to figure out that I also needed to press "Start!". It's unintuitive to me that a boat wouldn't move when you set its heading and the wind is blowing!
Thanks for a fun concept and good luck in your project. I hope this feedback is useful and not a discouragement. With some interface tweaking, this could be neat!