Ok, I finally finished the "Compression Post Repair", I'm going to attempt to recount my process of this fix for you.
First, after doing this repair, the best thing to do for this repair is to REMOVE THE MAST. You don't have to haul the boat out to remove the mast. Find a recommended rigging person, hire them to remove the mast for you, they can put it back up for you too, it's worth the $200 for each way. If you are going to do the repair, you are saving plenty of $$ by not paying a contractor to do the repair. I found with all of the repairing required it was safer and easier to work on the area.
I did this repair with basic knowledge, mechanical ability, wood and fiberglass craftsmanship. If you can use a jigsaw, sawzall, hammer, chisel, skill saw, mix epoxy and polyester resin, you can do the repair.
1 quart or polyester resin and catalyst
3/4 inch marine plywood, smallest portion you can buy, you don't need much
Colloidal Silica- West Marine 406
Low Density Filler- West Marine 407
14 X 10 X 3/4 Teak board
24 X 10 X 3/4 Aluminum Plate
Can Self Etching Primer
Can Black paint
So, here is the problem on my particular boat in the below pictures.
Basic procedure, after mast has been removed, I cutout a section of the cabin sole a little over twice the size of the aluminum plate I was installing. You need an area large enough to put the plate down and then slide it under the wood post and bulkhead. I cut out the two cabin sole mast supports, fiberglass in new supports, installed the plate, and lowered the cabin top. I then removed the bolts from the bottom of the metal post. I then jacked up the cabin top again. I removed the metal post, cut out the counter top, replaced the counter top portion with a teak piece, and the problem fixed. I have to replace my cabin sole, but with planning, you could still manage to save the cabin sole.
So, the first few things to do to prepare the area before jacking up the cabin top. I removed two pieces of the trim on the counter, one long piece of trim along the head door and meeting at the counter, I removed the head, head platform, and the angled wood and trim by the wood post. I removed the table from the screw on bracket at the slide bar.
I cut off the 1/4 teak cabin sole plywood, I will be replacing the cabin sole. I cut the floor back to the next aft floor support from the two under the compression post. I used a 1 1/2 diameter wood drill to drill hole I could then use my sawzall to make the cut out.
I plan to make the access area for the bilge, keel bolts, and compression post plate, as two doors instead of one door arrangement originally. While I believe my plate will last many years, I still want to be able to visually inspect it from time to time or replace if needed.
Floor cut out in the head
Floor cut out in the Cabin Sole
I used a non-hydraulic because I can control raising and lowering better, and the jack won't have the risk of bleeding off. I didn't get pictures of how I rigged the jack and boards because I was busy during the procedure with too many variables to snap pictures.
I put a 3/4 piece of plywood against the port sautee across from the head at the most forward portion. I then put a short piece of 2x4 several inches away from the plywood on the cabin sole, to create an even surface this is where the cabin sole on the port side starts to angle up and in. I then placed a 3/4 piece of plywood on the 2x4 and braced against the other plywood. I put the bottle jack on the plywood, placed a small piece 2x4 beside the jack between the plywood and jack to keep the jack from "kicking out". From there I measured the distance from the jack to the metal post by the flange by the bolt, cut a 2x4 a little shorter to have room to put it all in place and jack up. Make sure you have the head door "OPEN", the whole time doing the work. I then jacked up the cabin top about 1 inch, stopped when I heard the bulkhead cracking back by the starboard sautee. I was able to move the cabin sole portion under the wood post too. I then put wedged shims under the bulk head back by the starboard suatee and under the head door floor seal. I then let the jack down and removed the cut out piece of floor. I had a screw in the piece of wood to be removed right under the wood post. The manufacture obviously installed the 3/4 cabin sub-floor before putting in the bulkhead and compression post. So, I had to use a sawzall to cut the screw to be able to remove the piece of wood.
I then cut out the Two compression post supports and prepared the bilge and cabin sole area for epoxy.
Cabin floor aft support removed
Aft support after removal, you can see the supports are made of 3/4 plywood. The aft support was 2 pieces or 3/4 and the forward support was 3 pieces.
Head area ready for epoxy
Bilge and Cabin sole area ready for epoxy
I then applied the epoxy to the areas. I used epoxy to seal the area from water getting in to the areas. After the epoxy cured, about 24 hours, I then roughed up the epoxy, and then used polyester resin to glass the supports in place.
I used some flexible wire to make a pattern for the supports. I used polyester resin to glass 3/4 plywood, 2 pieces for the aft support, and 3 pieces for the forward support. I traced the wire and cut out the supports. I made my forward support the same height as my aft support, mine were not at the same height from manufacture, and the forward support did not make contact with the cabin sole on the other side of the bilge cutout. I had to sand the supports until i got them at the same level, and close to the original height of the aft support at original manufacture.
I had to add some support blocks under the cabin sole on each side of the bilge forward of the forward support to support the cabin floor. You need to do this prior to glassing the supports in.
I mixed up some polyester resin with West Marine 406, be careful on how much you add, too much, and the resin will harden to quickly. I then glassed in the forward support, mixed more resin, and glassed in the aft support.
Resin with 406
Glassed in supports
I then put some auto wax on the bottom of my aluminum plate, I want to be able to remove the plate if I need to at a later date. I then mixed up some polyester resin with 407, used for fairing out hull imperfections, etc, hard but sandable. I used this to "bed" my plate to the two supports. I then jacked up the cabin top, an installed the plate.
Plate installed cabin sole
Plated installed head area
I then let the jack down. I removed the screws from the bottom of the metal post. I then put a 2x4 cut to length to go between the bulkhead and the metal post. I had to do this to get the top portion of the cabin top to jack up some what evenly to be able to remove the metal post. This is the main reason for removing the mast, to fix the compression post, you need to replace the plywood between the metal post and the wood post in the head. You can get creative I suppose, and not do this, but I found it better solution. I used 3/4 teak wood to replace the counter top, they used teak between the cabin top and metal post, and it looked fine, so I went with it. I cut 14 inches from the corner at the head over. Getting the post in and out takes two people because of the wires running through the metal post.
Counter top fixed
I replaced the wiring for the mast at this point, mine were so corroded several lights didn't work, and the wiring was the problem. Just another reason to remove the mast during this fix.
One of the problems facing with the metal post, is where to bolt it to on the counter top. I used the old counter top wood to get an approximation, then I used a square placed next to the post. I had the square level and looked to see if the square was parallel to the post, did this from several sides. Once I was happy, I marked the bolt holes, removed the post, drilled the four mounting holes and the center hole. Put the post back up, used one through bolt for the mast ground wire, and three #14 wood screws for the others. I then let down the jack. I then put the teak trim pieces back on.
Squaring up the post
Cabin Top After Fix
Sorry for the lengthy post, but I wanted this topic to be covered in one post to give members who have an Islander 28 to see one of the few manufacturing flaws of the boat, and a way to fix it. I said manufacture flaw, not the designers flaw, the designer had the mast stepped at the keel, at least from what I have read about the boat. Bottom line is, it's worth fixing, I just love my Islander 28!!
Thanks for reading my lengthy post