I have sealed one window, but have not fully tested the repair so I will wait on reporting my methods. I have finished the deck plate work and took a few photos of the steps in progress, and would like to share my methods with the group. The deck plate began letting water in about two years ago and gradually got worse. I used 'Captain Tulleys Creeping Crack Cure' as a stop gap to removing the plate, and it did help for a while, but a permanent fix was called for by the mate.
Step 1. I used a garden hose with very low flow letting water run over the deck and not over the boot to be sure that the plate was in fact the source of the leak. Step 2. I removed the inside trim to better see where the water as entering. Step 3. With a flashlight and a dry hand I was able to find the location of the drip and determined that the plate had to come up. Step 4. I removed the boot cover and rubber boot from around the mast.
Step 5. I numbered all the wood wedges and put matching marks on each wedge and its mast location. I put corresponding numbers on the mast also. Since I did not want to disturb the tune of the rig, I wanted everything to go back exactly as it came out. Step 6. From the inside, I used a 1"x1" X12" piece of wood to drive each wedge out, working with the easiest ones first, and not in sequence. Only a few taps were required to pop out the wedges. The mast did not move in the opening. Step 7. I removed the 6 stainless screws holding the plate to the deck and used a putty knife and three large screwdrivers to break the plate free from the deck.
Step 8. I raised the plate and tied it up with a couple of pieces of line. Step 9. I scraped the deck and the under side of the plate to remove all the old caulk and salt. Then I used a wire brush on an electric drill to clean the groove on the underside of the plate. Since I could only raise the plate about a foot it was awkward to clean the plate bottom. I used a screwdriver to remove the old caulk from the screw holes.
Step 10. I used alcohol to wipe down the clean surfaces, and then masked the areas with tape. This really helps to keep things neat. Step 11. Caulk was applied to both surfaces, filling the groove and being sure to circle all the screw holes. I used White Boat Life Caulk which should last many years.
Step 13. The wood wedges were replaced immediately. The ones that fit snugly were set in place by hand in their original position, but about 1/2 inch high. The loose ones that would fall through were held to last. The very tight ones were driven in next which sort of repositioned the mast allowing the others to fit properly. The remaining ones were then tapped into place. I had three wedges that were still loose so I shimmed them and drove them in place. Step 14. The rubber boot and cover were replaced on deck and the trim was replaced inside. The whole job took about 4 hours and was not something to fear.