Jake,
Your assumptions are all correct. I was "B" in this race (H20) and "A" was an H17. As we crossed and got the overlap I asked what he was doing and all he said was "racing," which wasn't very helpfull. He's the best 17 sailor in the fleet and started 10 minutes ahead of us so I assumed he was also heading for the finish (he capsized earlier and was just trying to complete the course). If he had continued to keep me from heading up, I was in danger of hitting the committee boat. The wind had piped up by this time and we were all moving pretty fast so all of this took place in less than 30 seconds.