Repair mast step mounting core and cabin deck?

Leeward Rail · Oct 15, 2015

oh man.. that sucks. sorry to hear that James.

justsomeguy · Oct 16, 2015

IF the rot doesn't extend much beyond the immediate area, and considering it's a deck-stepped mast with a compression post underneath, you may be able to simply remove the rot and replace it with all glass.

Start by sounding the area with a plastic hammer or screwdriver handle to get a feel of how far the moisture has traveled from the tabernacle.

Leeward Rail · Oct 16, 2015

In my case all I did was remove and rebed the mast step. No Rot and No fibreglass required.
Cloud or hawk are probably the guys to talk to to. I don't doubt they'll chime in.
I can't see why you would need to do anything inside the boat.
The trick in my opinion would be to determine where the rot ends. That way when you fibreglass the panel back in place you have less repair to do.
Most tutorials I've seen used a series of small drill holes to determine the extent of the rot. Once repaired, the holes can be used to inject epoxy if needed. Similar to what I did when filling the space between the deck and liner where my furler cleat is.

Like justsomeguy says, if it's a small area, you may be able to remove the rot and fill with epoxy.

EDIT: I just checked the C22 Sailing Association Technical Manual, and there is a full write up on fixing deck rot around the mast step area on an early C22 on page 133.
I didn't find much with a complete forum search. Some threads mention repairs but none that I found explained the process.

Leeward Rail · Oct 16, 2015

On my new style the mast step is bolted through the deck to the compression post.
Your photos almost look like one of the fasteners was a large screw, and the other a bolt ? If so I wonder where the nut for that bolt is located

Leeward Rail · Oct 16, 2015

jmczzz said:
The compression post trim has some metal pins or bolt ends showing up in holes in the trim ring. Is that normal?

No idea. Your boat would have a wood compression post, whereas mine is stainless steel and doesn't have a trim ring at all.

Edit: I did a C22 compression post search on google and found this thread:
http://forums.sailboatowners.com/index.php?threads/compression-post-repair.144400/

In a couple photos it shows what the bottom of the liner looks like with the post out.
The lag screw goes into the middle of the post, with that trim ring around it.

Depending on the condition of the post, you may want to take the project further and make sure the whole step+compression post setup is in good shape.
Especially with your upcoming long trip.

Some threads, and the info on CD's compression post install kit, mention drilling a pilot hole, and using a longer 3-1/2" stainless lag screw, if the original is loose. it also suggested putting epoxy in the hole and re-drilling it if the hole is stripped.
http://forums.sailboatowners.com/index.php?threads/compression-post-bolt.170415/#post-1199620

If you had to do that, a better idea might probably be to epoxy a stainless threaded insert into the hole and replace the lag screw with an actual bolt.
http://forums.sailboatowners.com/index.php?threads/mast-step-lag-bolt-broke.140031/

If you end up having to fix the post, you may want to check out the bottom of it.
Besides the top thread I linked to above, another thread in the CD forums also mentions the support for the bottom of the post, inside the fiberglass trunk top being bad, rotted, or not even installed at all when the boat was built.

Leeward Rail · Oct 16, 2015

No worries. You may wish to check my previous post again because I was editing it when you were posting.
Reading further, it seems that on early C22s you can feel/inspect the support for the bottom of the compression post with your hand inside the forward seat.

Here's a photo from that other thread, showing the fibreglass cut away. You can see where there is an opening into the locker under the seat that should allow you to inspect it.

May as well check it all while your doing the deck section.

CloudDiver · Oct 16, 2015

jmczzz said:
lots of good info thanks for the help. James

James,

The rot in my deck was only around the electrical connector, water must have gotten in around the degraded bedding and screws. It seems that is probably what happened with yours, just only around the mast step bolts. It is likely that any rot is only isolated to the immediate area around one or both holes. The forward bolt should be a 1/4" bolt that goes through and has a washer and nut on the back just forward of the compression post on the inside overhead. The one that is center in the mast step should be a stainless 1/4" lag screw. If that thing is loose then the wood in the center of the compression post may be rotted, but it is teak so that shouldn't be the case.

Hopefully any deck rot is isolated to the area just around bolt holes, maybe both or maybe only one. You'll have to take out the compression post. The trim ring should only have three small stainless #6 screws, if there is more than that then it is a P.O. mod. Other than that there should just be two scows going through the port bulkhead plywood into the square body of the post. There should be no other fasteners besides the lag screw from the mast step. Take the bolt out from up front and then back that lag screw out. If the lag screw slips try an impact driver in reverse.

Use a small jack in the cabin, set it on a piece of lumber on the keel truck as far back as you can, then put a 4x4 block on it that goes up to the overhead. You pop top and companion way hatch should be removed when you do this but I think it would be ok to leave them on, it won't hurt anything. Careful placing the lumber, you don't want it to pop out under pressure.Just jack up the overhead just a little, it will flex the roof up just enough to slip the compression post out.

CloudDiver · Oct 16, 2015

Once you have the post out and mast step plates off you can figure out what is up with the two bolt holes. Don't jump ahead too far and drill out the holes bigger from the top, keep in mind you always need to be able to locate the exact position of the hole again and the way to that is to preserve the liner on the inside of the cabin. I'd drill out both holes to 3/8" first. Use a flashlight to look while you tap with a screwdriver handle or something. If the rot is isolated to not much farther you can tape off the bottom and just fill with unthickened epoxy. If you find the rot going farther out step up to a 1 inch or 1 1/2" forstner bit or hole saw, but only go through the top layer of glass, don't drill through the bottom! Once you have a bigger hole somewhere between 1 and 2 inches round you be able to pull out any rotten plywood until you start to find clean bright wood. If that is where it ends just tape the hole off inside the cabin and brush the void with unthickened epoxy first and let it kick off and get tacky, be liberal when you brush it on so it soaks into whatever wood is around the edges. While its tacky mix up some thickened epoxy and fill it almost to the top, leave just enough room for a few fiberglass patches. If your hole is only 1 to 1 1/2" inch in diameter you wouldn't even need the fiberglass, but if your hole gets bigger than that I would do it.

CloudDiver · Oct 16, 2015

I'm not sure if you have paint on your cabin or still the gel coat, but either way I hope the holes you have to drill into the top layer don't go beyond the area the mast step will cover... that way you don't have to worry about repainting or anything, the mast plate will cover the repair.

Anyway, if your compression post or trim ring is messed up let me know, I'll send you mine. They never go for more than $40 on ebay anyway, i wasn't even going to bother trying to sell it.

Leeward Rail · Oct 16, 2015

Luke, you rule.
Did you ever check the post's support on your boat ?

CloudDiver · Oct 16, 2015

I think there are pics of that somewhere in my thread. When I was fixing the gel coat voids I dug into the corner right next to the compression post. Other than the extra glass I packed into the void I was pretty happy with what I saw. There is a 2 x 4 laminated into the structure vertically and it had not gotten wet. The small corner of it that was not coated in resin did get coated with the new glass when I packed the void. That 2x4 takes all the stress from the compression post sitting on the support, and the layers of fiberglass of the cabin liner and the keel trunk make a pretty thick sandwich.

I wish I had taken a pic of what the inside looked like, but this gives you the general idea. Behind that glass patch I soaked shredded glass scraps in resin and stuffed them inside the void. What you see isn't actually that close to where the post bottom sits. The 2x4 is in there and sits square under the post. I used polyester resin because I needed the polyester filler and gelcoat to be able to stick to it. Gelcoat won't stick to epoxy, or so I have been warned... I've never tested that theory.

Leeward Rail said:
Luke, you rule.
Did you ever check the post's support on your boat ?

Leeward Rail · Oct 17, 2015

While my mast step area is nice and solid, this has me wondering what the deal is with the new style compression post's support.

It appears that Catalina used wood 2x4 supports on some of the their other boats too, and on the Catalina 27 and 30 the owner discussions mention that many of them rot.
I guess it really depends on if the guys were paying attention to the details when building the boat.
Hopefully the C22 new style's support is easy to inspect. It looks like it should be.