Don't worry so much Blast. I spent five years on tugs in NY harbor, and I never knew of one tug captain that used a kayak as a speedbump. However, that might not stop a tug captain from calling a kayak a speed bump.

As far as right of way, the Rules of the Road would normally require a motor vessel to yield to one without a motor. The practicalities are that sometimes it's simply not possible to do anything to do so.

I will admit that I might have sunk a rowing shell once. I was light boat, heading somewhere fast, and when I came through a bridge, there was a rowing shell on the other side, about 1/3 mile away. I was gone by the time my wake reached them, but I bet they swore at me.