Ahoy, Yes, I know nobody asked me, but this forum needs a little shot, so Here's a little "Cutwater" fitting story and a little info.
Once upon a time. I was delivering a boat back from Okinawa, bound for Astoria, Oregon. On about day 8 the automatic bilge pump quit working. Didn't notice this. Soon the floor boards were awash. Pumped rapidly for quite awhile. Discovered the cutwater fitting hole was leaking badly but we could not do anything about it from inside the boat. My crew and I pumped 200 to 300 gallons a day (not a misprint) for the remainder of the 39 day crossing.
The boat owners did not know they had a problem. The cutwater fitting was out of the water when the boat was stationary, and the automatic bilge pumps took over when the boat was moving. The boat had been a full time cruiser for about 3 years, and they had always anchored off of this fitting. That means it had been subjected to about 1 million side load cycles. Each cycle just very slightly opening up the slot and breaking down the fiberglass backing.
I, personally, do not use a zinc on the cutwater fitting. I keep the fitting out of the water. Also, I use a forked end on the bobstay for this fitting. It is more streamlined with less parts. From a performance point of view, this is just one piece of a 1000 piece puzzle.
Note: This is only one of my "Cutwater" fitting stories.
Thanks, Dave