I drilled though both gunwhales, just beheath the deck. I epoxied in place, a segment of "G-10" fiberglass tube through these holes. I then ran some Amsteel line through the tube and applied a stainless steel washer on the outside gunwhale to deck corner to carry the majority of the load.
I was careful to run the glass tube relatively in-line with the direction of the pulling force.
GARY