Replacing the old Groco rubber plug
seacocks with modern Groco seacocks was my first major boat project
- it was fun! Like you I researched different backing plate materials and settled on marine plywood
because it is so easy to work with. The flange can be screwed into a pilot hole in the plywood
, no worries about tapping or stressing the material/breaking a bolt or screw because the pilot hole was too small.
Boards are bad because they can split. I used okumi (sp?) plywood, numerous thin, tight laminations with water
resistant glue and no voids. The shape depends more on the room you have available for the backing plate; for me, triangle wasted the least amount of wood and was easier to cut, and fit to my curved hull
. A circle wastes more material, but you don't have to worry about orientation.
"And I need a good sander to remove the 3 existing layers of bottom paint
in preperations for the barrier coat."
No no, I think there is a West Marine
in KW, use a paint
stripper, Aqua Strip is easy, fast, non-toxic, and kicks ass. Sanding/grinding is hard to control, messy, and contaminates the underlying layer.
Tips: You Will need the Groco thru-hull wrench thingy. I am THE Master of Improvisation and finally gave up and bought the almighty Groco thruhull wrench thingy.
The thruhulls are long, you will need to trim them, I cut mine to leave two or three unused threads when the thruhull was fully screwed into the seacock. A cutoff wheel
on an angle grinder rocks. Wear FULL eye protection. Put the hex nut on the thruhull before cutting it, then you can straighten the threads as you screw it off. File sharp edges.
Buy extra sealant
, if you don't get lots of squeeze-out from everywhere, remove the thruhull and add more. Many people recommend 5200 - that product is an adhesive
, not a sealant
. You don't need an adhesive
, it won't make the installation
any stronger or more waterproof, and is a mega PIA if you need to remove a seacock for some reason. Polysulfide is recommended for below the waterline use, and is also a water-cure product.
If you didn't know, WEST Epoxy
System has numerous instruction booklets for download on their web site, and if you need more help then call them - a friendly live human answers the phone
and immediately connects you to a live human tech who will help you with any problems.