For added context, this was at a long, narrow lake that is very sailing oriented, and a relatively famous racing venue.

The incident occured at the narrowest end, where it is ~ 200 yards wide. The fishing boat was ~ 50 yards from the shore. I was approaching him from the shore-side. When I fouled his lines I was more or less perpendicular to his course.

If I had realized that there were lines in the water, I would have tacked although I would have had to tack back very quickly and I'm not sure I could have cleared his bow after the second tack as he was motoring upwind.

I guess I could have slowed up, ducked the A Cat and bore off but as the lines were right on the surface I would have had to go dead downwind to clear them once I realized they were there. In that case the A Cat would have been the one to foul his lines.

With fore-knowledge, I could have ducked the A Cat and tacked early on the first leg after the mark, but that would have sent me into the traffic heading downwind to the mark.

Of course if I was a motorboat I could have just gone in front of him. There are reasons that sailboats have rights over motorboats, and it's not just about speed.