Hull Restoration

[Flitch]

Hey Guys,
I must concede that you have tired of my thread, "Hauling the Skyla Brianne", despite my excitement.. that's okay.. but you left me with my pants down in a manner of speaking... I have more jobs on the go than I can shake a stick at! That being said I will post my problems under separate threads, praying for your collective wisdom...
I have had the 16 ton Skyla Brianne in my backyard for a month and work continues as work and family allow.. sigh.. the starboard side is pretty much scraped and sanded to bare wood and I have begun replacing the dead wood (skid plate?), if that is what the 2x7 under my keel is called. The front deck is clean of winch and skylight and last weekend saw me on a road trip from Gibsons to Victoria shopping for goodies... I spent $12,000 on everything from a new skylight, new hatch, davits, spot lights, new diesel stove, diesel furnace, 280' of 2" manilla rope, a new trailer to haul it all home on and lots of seam compound (3m 4200), oakum, cotton and packing (Oh and a rebuilt Nissan Diesel engine for another boat I have on the go)...
Anyway, that brings me to my hull... red cedar on oak frames, been drying out for about a month... here look:
http://www.flickr.com/photos/kootena...7602065016923/
I have been cleaning out the old seam compound, tightening up the oakum which is starting to show daylight, and then running a bead of 3M 4200 seam compound... it's $18 a caulking tube and going fast... as it cures I am sanding off the excess and it's looking good... so here are the questions....
1. Am I doing anything wrong? Should I leave the daylight between the old oakum and frames and just seal it up? It's seemed natural to use a thin dull chisel to knock it in about 1/4" but of course that mushrooms it...
2. What shall I do with my nail holes? Below the waterling I can just use the excess 4200 to refill them (I have picked out the old compound and shined them up)... What do I do with them above the waterline? clean them up, paint them with a couple coats of stain killer, fill them with...?

Okay... Thanks... Now on with my Rudder Project Thread...
Flitch

[pcford]

1. Am I doing anything wrong?

4200 is not an appropriate seam compound. Polyurethanes are too stiff.

[Ian McColgin]

4200 is stiff enough that it’s likely to over-compress the planks, stressing the fastenings, when she gets wet and swells again. If you can see daylight, there's no caulking. I mean by caulking the oakum and then cotton roping that’s tapped in between planks. This could be a very big problem, even if you’d not started with the 4200.

A carvel hull is a skin compression structure where once swelled the planks need to exert a little strain against each other. Something purely hard won't work as the boat had drying cycles and it's hard to get something hard to final set just as the wood reaches final expansion. (There is a role for cement as a seam finisher below the waterline but I won't go there.)

You need something that, when it and the boards and all have swelled, is almost like direct wood on wood contact. This is what keeps the fastenings from wriggling about and failing early.

This rigidity is much more important in sailing boats, with their wracking strains and all, than it might be in power boats. I'm taking it that since you see daylight, there's no caulking. I’m not a qualified marine engineer and maybe old trawler hulls can get away with stuff that’s death to sail boats so . . .

First thing is the boat's history. If, in pow-wow with a competent surveyor, an honest record of the boat's history, and a look at some fastenings, you find that this construction can work without oakum, then use whatever glop the surveyor recommends and G'luck.

I think you'll need to get a caulking mallet (nice thread down in recourses) and appropriate sized iron and a few miles of oakum - seams look large enough to start with oakum, add cotton over that, and then a seam slick. There is a good chance that one here – Dave Flemming? – can give a general essay on what sizes of oakum and cotton you need for whatever planking thickness, but you may need one of the standard books or a caulking rabbi.

It's well to red lead the seams before doing anything and run a little red lead on the cotton before adding the seam slick.

I like good brand underwater seam compound mixed about 50/50 with roofing tar - makes a slick that really works. The slick can be loaded into a grease gun for better squirting than dabbing on with a putty knife.

Hope this does not over discourage but you’re off all my charts right now.

G’luck

[kulas44]

After awhile you kinda figure out where and what to buy so the money flows out a little slower. Just because something has a boat on the container doesn't mean it's the best product for the job. Take 3M 4200 for example, good stuff but 18 bucks a tube ? You won't be able to tell the difference between it and PL Door&Window at 5 bucks a tube, they are identical as far as I can tell, and yes I have compared them, side by side. A lot of carvel planked boats have been "caulked" with polyurethane (the 4200 is pretty soft, so it can compress, it leaves a bulge when the planks take up) and it has helped save some of them. A good way to do it is to clean the seams out with a skill saw or router, getting to clean raw wood. The urethane sticks to it much better and it gives a bigger gap so the goop can handle the take up compression better. I do think however, that these are last ditch efforts to keep an old boat floating, and if possible you should use a traditional approach, i.e., dry it out, reef the seams and recaulk.

[oakman]

I will have to second the opinion that polysulfides are the wrong thing to use in the seams for all the above reasons. Return the rest of your stock and buy a couple cans of Dap 33 glazing compound, mix with some linseed oil and red lead primer to thin and help keep from drying and use that below the water line. Much cheaper, lobsterman use it in Maine all the time and I have used it with much success on my own 1915 Crosby Catboat.

Prime the seams with red lead before you start caulking and paint them after you are done. Then apply the compound. In the end you will be much happier.

[Ian McColgin]

Still worried about whether you can really see through - no okum and cotton - or whether that's metaphorical. . .

[Flitch]

Relax guys... no I am not seeing full daylight through all my plank joints... just a couple spots where the oakum wasn't as thick. For the most part my oakum is good and with a month of warm weather on her, I can see the joints have opened up about 1/16". With the removal of the old seam compound, I have about 1/4" deep joints and the 4200 seems to stick good and remain flexible yet sandable. My question was whether to use the seam compound over the oakum with it's 1/16" spacing or to use my mallet and iron to mushroom it in a little further first? Bear in mind that this is the dryest boat I have ever owned... she had only one spot right on the nose at the waterline where the oakum took a shot and I have repaired that. I will shop around for PL Door&window as well as Dap 33... No idea where to even start looking for red lead!
PS What about my nail holes? Is there a better filler for above the waterline?
Flitch

[oakman]

Flitch

The Dap 33 is a window glazing compound and I use it because it is an oil based putty. You want to put something in your seams that will stick, ye is fairly easy to remove. Suppose you get somewhere and she springs some oakum and starts taking on water. Well you have a tide and can get to the spot but now you were wishing for a heat gun to soften that 4200 or worse you split plank edges getting it out because you have to reef so hard. You will then wish for a putty that has not dried and has just enough stick to hold it in.

You will regret using the PL as it is glue.

[kulas44]

PL door&window is a SEALANT. PL Premium is a GLUE. PL d&w is as much a glue as 3m4200, just way cheaper.

[Flitch]

She's a fresh water boat now... no tides here in the interior and the lake I run (Kootenay Lake) is usually like glass. I will try the PL Door&Window as well as the Dap 33 and report back. What about my nail holes above the waterline?
Flitch

[Lew Barrett]

She's a fresh water boat now... no tides here in the interior and the lake I run (Kootenay Lake) is usually like glass. I will try the PL Door&Window as well as the Dap 33 and report back. What about my nail holes above the waterline?
Flitch

Bungs if large, fairing epoxy if small. Put some sort of sealer on the nailheads if you can. Attractive design you have there.

[Flitch]

Found something interesting...
http://www.rotdoc.com/L/BoatL/QA047.html

Funny they would recommend 3m 4200 the same way I have been using it. I knew I read it somewhere.
Flitch

[oakman]

Yes Flitch, of course you can find references for polysulfide use in seams all over the place. That does not mean it is the proper thing to do. Overall the beauty of wood boat, in my opinion, is their repairability and anything that hinders that for the future should be carefully thought about. That is why I have tried to give you scenarios to think about. Here is part of the issue, that polysulfides while flexible, will only compress to a point, after that the wood will compress and the next time she is hauled and she goes through the dry, swell process she might not return to water tight. If you use a compound that never dries, it is squeezed and will not damage the plank edge. It is the three elements that keep the boat water tight. Swelling of the planks, swelling of the cotton and oakum, and to a lesser extent the seam compound.

Also, who knows what products are soaked into your planks? Good clean bare wood is a good bonding surface for your polys but do your have that? On my boat I way able to pull the polysulfide they had used out in long strings because after a couple years it had let go. A proper oil based putty seam compound may be comprimised in an area but the whole seam filling is not chemicallly bonded so you do not risk the whole seam if one area fails.

Also, if you do get good adheasion and you need to make a repair in the future the stuff can cause a great deal of damage in reefing it out. Bottom line is oil based putty works better, is better for the boat, and cheaper. OK last of my comments on seam compound.

oak

[Jay Greer]

My favorite material for filling nail holes above and below the water is a mixture of micro balloons and epoxy. Often a tape dam is needed around the hole to prevent the mixture from drooling down the hull.
If you are interested in preventing an iron fastening from rusting, once it is cleaned, it can be painted with a liquid galvanizing primer known as "Devcon-Z".
http://www.devcon.com/devconfamilypr...d=115&catid=21
Jay

[Flitch]

Hey Guys,
I found some Dap 33 and gave her a try today... wasn't nearly as sticky as the 3m 4200 and I have my questions if it' s the right thing to do... have a look and see what you think.
http://www.flickr.com/photos/kootena...7602065016923/
http://www.flickr.com/photos/kootena...7602065016923/

I have two gallons of cpes coming on the stage coach next week so I'll apply CPES and compare Dap 33 with the 3m 4200.
http://www.flickr.com/photos/kootena...7602065016923/
I tried to pull some of the 3m 4200 from a week or two ago out today and it sure bonds well... great adhesion and when I pulled some excess off it's quite elastic... like a tough chewing gum.. I still think that it will absorb the expansion of my planks and simply bulge out a bit without stressing my fastenings.
Here's a pic of an untreated joint (after sanding and old compound has been removed).
http://www.flickr.com/photos/kootena...7602065016923/
Flitch
PS NO PL Door&Window in my area... lots of PL Adhesive. Oh and thanks Jay.. will find some Devcon-Z.

[oakman]

No, the Dap will not be as sticky as the 3M for sure, but you don't need that much stick here anyway.

BUT, you should be priming the seams with red lead before you drive the cotton and oakum and then it is critical to paint the cotton and oakum with red lead directly after it has been driven. This helps to keep the products from moving while the planks swell and also serves to prime the fibers so that they will not absorbe the oils from the putty. Once you have applied the putty, the excess should be scraped away from the seams and a slight concavity presssed into the seam so that when the planks swell the seam will push out flush to the plank surface and not crack your bottom paint.

I usually work in the following order: prime seams, caulk, prime caulking,finish caulking entire hull, prime hull, pay seams, apply bottom paint.

Once the cotton has been painted you can wait to pay the seams for as long as you like. Remember that the beauty of the oil based putty is its repairability and removability with minimal plank edge damage.

[Flitch]

Thanks Oakman,
I have a line on Red Lead from Vancouver so I will try it your way.
Flitch

[oakman]

I find the Dap out of the can to be a little thick, thinning with some linseed oil and a little red lead will help and make it a little stickier, the red lead will give it a little poisionus bent which the organisms don't like.

[Green Boat]

between the seams use epoxy and sand dust and for the fastening holes make plugs out of the same material as ur planking.