The fastest SOG we ever recorded in our big, heavy, slow 7 knot girl was 13.4 riding the flood through Cattle Pass. Got a bit too squirrly at the end, though. We nearly got thrown completely sideways a couple times!
We've hit 11.5 in the Port Townsend canal before, but for some reason we typically transit that thing against the current. We're more used to making 4.5 through there... Enjoy it when you can!