This morning I was able to speak with John at Groco about the installation
details. John was very helpful, and it became clear that I have made one mistep in the process using teflon tape on the tapered inside thread IBVF+IBV+Hose Fitting. (I am thinking of leaving it as I have the joints very tight and I don't believe they will leak. I have done plumbing
joints with 50-60 psi this way. If I were to do it again, I would certainly use the paste.)
A. Assembly of Seacock Parts (just the parts inside the boat)
1. IBVF (Flange) + IBV (Valve) + Hose Fitting Threads assemble with sealant/lubricant (Teflon Paste). Do NOT use teflon tape because it is just a lubricant. Some installers like Terra Nova use Highside Leak Lock and some others use a marine
sealant. Tighten these parts quite tight (refusal).
B. Groco Backing Plates BB-1, BB-2 Installation Details
1. Sand down area, remove all gelcoat
, so it is smooth and reasonably level, obviously take care to leave hull as intact as possible. If the boat is cored construction below the waterline, you will need to remove core
in the entire area and inject epoxy. Clean up. Also sand and prepare the outside of the hull, removing all paint
and leaving a good surface for adhesion and sealant. Acetone surfaces on outside and inside to remove all wax and contaminants.
2. Hammer the three threaded brass ferrels into the Groco BB backing plates holes, taking care to use the appropriate holes (each plate is setup for two different IBVF bases). Ferrels should be flush. Lightly scuff up the back with sandpaper for adhesion and round the top edge (the edge away from the ferrel hexs.)
3. Get the necessary bolts, in my case 5/16"-18 x 1" Silicone Bronze. Use them to secure the inside valve assembly into the backing plates top side (the side away from ferrel hex heads). Hand thread the thru-hull fitting from the outside to help position the inside assembly.
4. Orient the inside assembly so the handles and hoses work properly. If needed, relocate the handle hex nut to allow the handle to move in the opposite direction. Adjust any angled hose fittings. Mark the position and orientation on the hull and the backing plate. Remove the valve.
5. Prevent epoxy from entering the threaded ferrel holes. Spray the bottoms of bolts with WD40 to prevent epoxy from sticking, and screw them in to the bottom of the plates flush with the flange and valve fully assembled. Don't get excess WD40 on the plate or the ferrels.
6. Use West Marine
Six Ten two part epoxy cartridge to secure the Groco BB Backing plates. Carefully twist to bed the backing plate and align the plates with the hull hole. Avoid getting epoxy on the bolts. Clean up the extra epoxy and fillet the excess into the Groco BB Backing plate. Use small two small clamps to secure the plate from sliding if necessary. After setup clean the hole out and sand the top plate level if necessary. Remove the bolts.
C. Dry fit the entire assembly
1. Dry fit the full assembly using the bolts, hand tighten. Thread the thru-hull fitting from the outside. Screw it in by hand so it turned all the way in. Verify from four locations, that the mushroom will bed properly on the hull, with a tape measure.
2. Mark and cut the thru-hulls. Label each thru-hull for location on the mushroom. With the thru-hull turned in, mark the hull location with a black marker on the threads. Remove thru-hull and transfer that depth
to the end away from the mushroom and add 1/4", and mark that thread all the way around. Carefully cut the end of the threads off with a metal cutoff saw, dremel and small diamond wheel
or hacksaw. Finish the raw end and carefully remove burrs and blend the starting thread so it is gradual.
3. Screw the thru-hulls back into the appropriate locations, so they are hand tight and the mushroom is against the hull. Make any small adjustments needed. Tighten the thru hull
a final time and check that the flange and mushroom are well seated and ready for the final installation with sealants and adhesive
. Carefully turn the bolts in and make sure they do not bottom out, if they do, grind the ends a little and check again.
D. Prepare for installation
1. Remove the thru-hulls and inside bolts.
2. Acetone the surfaces.
3. Tape the outside and inside surfaces, mark the outlines of the flange and mushroom and cut and remove the tape so the flange and mushroom will bed.
4. Get materials in order. Gloves, paper towels, rags, 3M 5200, 3M 4200 or Silkaflex 261 (your decision). At first I thought of the IBVF as permanent and was going to use 3M 5200, but I just removed 5 valves with 5200, so I am using 3M 4200, rather than 3M 4000uv which is just a sealant.
E. Installation of the Seacock
1. Apply 3M 4200 (or your choice of marine sealant/adhesive) to the face of the IBVF Flange. Set in place and screw in the bolts very loose so that you can thread the thru-hull easily.
2. From the ground, test thread the thru-hull to make sure you can start it. Then apply 3M 4200 to the heavily to the hilt of the mushroom and more evenly to the entire threaded area, see this Link
. Screw it in hand tight.
3. From inside the hull, tighten the bolts evenly and snugly. Cleanup the major goo mess.
4. From the outside, use the seacock thru-hull wrench to tighten up the thru-hull, but not over tight, the idea is to simple get a water tight seal. It should be snug and tight. Pull hard on a large crescent wrench and that should be good enough. I do not need the full leverage of the 4' turning bar that I used to break the old 3M 5200 seals
. Clean up the major goo.
5. From the inside, check the seacocks, tighten the bolts a final bit and then final cleanup.
6. From the outside check the tightness off the thru-hull and final cleanup.
7. Let it setup overnight and remove the tape.
F. Bonding Wire and Lubricant
1. Bonding - Add or connect the Bonding wire which should be at least #14. Use the bonding bolt on the IBVF.
2. Lubrication - Remove the drain plug
. Insert a Zirc Fitting 18-27 and use a dedicated new cartridge grease gun with a Dow 111 Molycote cartridge.
Barely crack the valve open, and fill the valve. Remove the Zirc fitting unless it is stainless and replace the plug
Many thanks to John at Groco and all the others who have helped.
I have been taking pictures and will add those later.