I've been here and pretty frustrated too ... someone running down the line spins up and parks in front of a crowded line of boats that are moving. Remember that that parking person has to allow the boat behind him time and opportunity to avoid him...he can't just spin up willy nilly swinging their sterns under your spin pole and expect to be in the right.
Jake, yes, you have the gist of it. Rules 15 (Acquiring Right-Of-Way) and 16 (Changing Course) basically say that when you change the relationship between your boat and another, that you have to give the other boat the opportunity to keep clear. There are the caveats, but that is the general idea.
The more I've learned about the rules, the more I'm impressed with them in two ways: (1) They don't contradict each other, and (2) it is almost impossible for one boat to make another break a rule - without breaking one herself. There's nothing to prevent you from putting yourself in a bad position, but nobody can force a penalty on you. I'm actually surprised at how well a relatively small set of rules (Part 2 is only 6 little pages) covers all the situations where boats meet on the water.
Regards,
Eric
