bottom (floor) cleats - replace from top?

[Thorne]

Gosh - from the design to repair forums within hours of buying that 18-year-old Chamberlain dory skiff!

;- )

As on my previous Banks dory, the oak floor cleats (the crosswise pieces of flat oak that hold the three floor boards together) range from a little to very rotten from water damage.

Since the new dory has a very well-attached second bottom of plywood, I'm interested in cutting the rotten cleats out and replacing them with new oak -- fastened from the top.

If I dry all the wood well, and use our local Smith's brand penetrating expoy sealer to kill the rot, then epoxy and screw the new cleats to the floorboards - think that will work?

http://www.smithandcompany.org/CPES/index.html

The thick oak frames and thinner steamed oak bent frames are in OK shape, a few of the latter have cracked where they bend up to the sheer strake.

http://luckhardt.com/closeupframes.jpg

[Bob Smalser]

Originally posted by Thorne:
Just bought a boat tonight that seems to be a Chamberlain dory skiff. Fir over steamed white oak frames, built at the SF Maritime shop in the early 90's for a class. I'd go over the rest of the boat with an icepick thoroughly....it's pretty new to have those kind of rot problems already.

I don't see any floor boards. I see a dory-built boat with a traditional, cleated, 3-board bottom.

If those are your cleats, then CPES won't kill anything except your lungs. Get the boat level on sawhorses and remove the old cleats one at a time. If there's any softness or punkiness, then use them as patterns to make new ones using White Oak or Doug Fir heartwood. Don't try to save them. Make bigger limbers while you're at it.

Rot is very contagious. If there's any sign of rot or softness in the bottom planks beneath, then they'll need repair, too. If they are hard but just discolored, then those are the spots to use CPES on, to seal in any remaining rot damage:

The plywood dory bottom below doesn't look bad after the punky frames were removed, does it? Just a little discolored, right?

http://pic3.picturetrail.com/VOL12/1104763/6771586/112592880.jpg

Well if I'da bought into that wishful thinking, I'd be repairing that dory again in a few short years instead of twenty or thirty:

http://pic3.picturetrail.com/VOL12/1104763/6771586/112592879.jpg

Coat your new cleats in red lead or copper bottom paint if you can't get red lead and then bed them to the bottom planks using more red lead. Then alkyd enamel paint atop.

Forget the epoxy in a crossgrain plank to frame joint in solid wood. The planks will crack without the "give" of fasteners and bedding. Dunno if that plywood false bottom will cause the same problem...but it isn't a good practice atop solid and it might if they also glued it down.

Wood screws have to go from soft to hard. If your cleats are of harder wood (like oak or fir) than the softer bottom planks (like pine or cedar), then the screws go in through the plank bottoms into the cleats so the threads hold in the harder framing wood. No exceptions. You can remove any false bottom or you can screw through it, countersinking and plugging the holes.

If you screw hard framing members into the soft planks rather than vice versa, you don't have either framing members or planks...for very long, anyway. ;)

And while I was in there, I'd also replace any cracked bent frames I see between the sawn frames.

[ 09-21-2005, 02:42 AM: Message edited by: Bob Smalser ]

[Thorne]

All very good advice!

I'll probably end up pulling the false/second bottom so I can get to the bottom planks from both sides.

The boat is built almost exactly to Gardners plans, which include the use of a false/second bottom made of sacrificial plywood, fastened from the bottom up into the floor/bottom planks.

One exception is the rail/gunwale cap, which is build of three pieces and easily 4" wide. I hope to strip and epoxy/varnish this to show off the construction.

It also has a 3" wide, 5/8" by 4' long cap underneath the two rowlock pads -- the previous owner was a BIG guy. I'll probably pull this to make sitting on the cap more comfy whilst sailing.

[Bob Smalser]

Also install a drain plug in either garboard or bottom to prevent recurrence of water collecting in the bottom, causing rot.

http://pic3.picturetrail.com/VOL12/1104763/6771586/112605343.jpg

These are floorboards.

[ 09-21-2005, 09:41 AM: Message edited by: Bob Smalser ]

[Thorne]

Yeah, I've seen Gardner's mention of that plug for other boats -- I'll certainly have to install one
!

Does anyone know if the 'sacrificial' plywood bottom on these dories should be treated in any way? I'm tempted to at the very least soak it in penetrating epoxy sealer, and even more tempted to seal it in epoxy on both sides.

Yes, putting real wood and plywood together can cause issues, but so can having the plywood rot and infect the rest of the wood. And since Gardner himself suggested it...

;- )

[ 09-21-2005, 02:01 PM: Message edited by: Thorne ]

[Bob Smalser]

I wouldn't waste that kind of money on a sacrificial bottom. Anyway, it's already painted and nothing but paint's gonna stick to it well. But with al the rot already there, it probably should come off for a good inspection.

Pull it off, sand, prime it and the 3-board bottom with red lead followed by alkyd paint and screw it back down using an oil-based, non-adhesive bedding compound like Dolphinite.

[Thorne]

At this stage I've got several choices:

In any case I'll pull the ply bottom off, treat the bottom planks inside and out with penetrating epoxy sealer, attach the new cleats from underneath (soft to hard).

A. Replace ply bottom with new marine grade ply, and bed in non-adhesive compound, then paint outside.

B. Replace ply bottom with two oak planks running fore and aft on either side of the main floor plank -- this is shown (I think) in Gardener's plans. Bed as above.

One issue with choice A is how to treat the plywood - should it be sealed or left alone? Since it will swell and shrink differently from the fir bottom planks, does it make much difference how I treat it?

The issue with choice B is that I've had a dory with bad bottom planks, including worm damage where they join the garboard planks -- and that is a serious problem in a dory! So the temptation is to protect those bottom edges as much as possible, and the ply bottom does just that.

[Canoeyawl]

I have bedded sacrificial plywood planking using soft copper bottom paint with good results. Most bedding compounds seem to thick for that much area and caused "pillowing" or a quilted effect when fastened.

[Bob Smalser]

Originally posted by Thorne:
At this stage I've got several choices:

In any case I'll pull the ply bottom off, treat the bottom planks inside and out with penetrating epoxy sealer, attach the new cleats from underneath (soft to hard).

Treating anything with paint/sealer residue on it with CPES is a waste of a whole bushel of money. Confine CPES to sealing up residual rot in raw wood before graving in new wood. The rest is mostly marketing hype....red lead and alkyd paint will serve just as well.

I'd have to pull that false bottom off to see whether I'd replace it with oak or DF, more plywood, not replace it at all, or simply reuse it.

Getting it off without further damage isn't a given.....hope it's not glued down with 5200 or worse. I'd have a length or piano wire handy rigged as a garrote to "saw" it off if I had to.

If the bottom planks are 7/8 DF or thicker, I might leave it off and fabricate triangular bronze or SS skid plates around 10" long fore and aft to protect the garboard-bottom joint where they first hit gravel.

If I were expecting to regularly skid the boat via winch above the tide line, I might add the two runners you describe behind the skid plates.

Or I might just reuse the plywood if it were sound and I wanted to economize. Insure all faying surfaces are primed and painted and you can bed it in about anything non-adhesive that's inexpensive.

Copper bottom paint and its regular maintenance are what prevents worm damage. False bottoms protect from abrasion and add a lot of weight....depending on how you use the boat, you may not need one at all.

[ 09-25-2005, 11:43 AM: Message edited by: Bob Smalser ]