I was racing on Sunday and had the following situation.
I was next to and slightly behind a cat, both heading towards some moored boats. I was matching it's speed. Well almost
See really bad drawing below.
We were both close hauled on port tack.
I wanted to sail in as far as possible to get a better line to the next mark.
I was not sure who had right of way here so I kept going till something was said.
I constantly kept looking around my #1 to keep an eye on them as the #1 was blocking my view.
The crew on the cat eventually signaled they were tacking. So I tacked, and didn't make the mark.
I am pretty sure it is this rule that applies.

12. On the same tack not overlapped.
When boats are on the same tack are not overlapped, a boat clear astern shall keep clear of a boat clear ahead.

Was I in the wrong by waiting for them to say they were tacking?
It was a long race and I didn't get a chance to get back to the clubhouse to ask anyone.