Canvas Decking - Again (but with a twist)

[ARW123]

I have a 100+ year old 30’ River Cruiser (sail) that has had the deck covering replaced with the ubiquitous “Trakmark” over planking, which is now completely shot. I have been researching alternatives which will exclude the modern Trakmark equivalent as it is now supplied in 1.2m (or 2.4m) x 0.9m sheets not a roll, and also I will not be contemplating the much vaunted epoxy over ply solution.

This leaves me either linoleum or canvas. Having read with great interest Jay Greer’s posts on this subject, canvas seems to be winning the argument. I have however a few questions:

· Trakmark I’m sure will have been affixed with some horrible latex type contact adhesive – will this need to be removed (I think I know the answer to that one!), If so what in your experience is the best method?
· Does surface preparation of the deck require priming / sealing?
· If sealing is required – what would be the choice and does this depend on the bedding compound used?
· If covering in one piece is not possible and joints cannot be avoided, what is the approved method of a achieving a waterproof solution? I believe locally this would have been achieved by covering the joint with tacked copper “tingles”, I do not know if a lapped or butt joint is required though.
· Would you advocate the use of a modern flexible sealant under the quadrant surrounding the base of the cabin sides or under rubbing strakes? If so any thoughts? (I have tried Sikaflex under steamed oak gun’lls before and not been impressed with its shrinkage – Wurth “All Weather Sealant” however seems to be very tolerant, but I’m not sure of the technical specs or name of this type of material)

[Thorne]

More info will help -- what is the current deck materials and dimensions of same? Gaps, splines, caulking, etc?

[ARW123]

Thorne:

Current material - softwood possibly redwood, T&G over deck beams about 1" x 2.5" and 18" centres.
Dimensions of planking - Width: 4". Thickness: unsure current covering still in place and planking not exposed.
Gaps - minimal.
Caulking - unsure current covering still in place and planking not exposed.
B.T.:

Thanks, awaiting download.

[Bob Cleek]

Yea, I just skimmed the article in the latest WB. It's nicely done and well written, but there are a few critical errors, or shall we say, questionable practices there.

First off, I am completely familiar with Arabol, which actually was pretty much the same stuff as Elmer's Glue. It was, in fact, at one time manufactured by Borden's Dairy Products, which makes Elmer's out of processed milk, I believe. I NEVER saw anybody who used Arabol on canvas decks, EVER. I'm sure somebody may have tried it, but were sure sorry they did. Canvas decks are saturated with paint, not glue. Canvas decks are NOT glued down with Arabol or anything else. They are laid, ideally, on top of Irish Felt and are not stuck to the deck underlayment in any way and then sealed with paint. (Fibreglass cloth and Dynel are 'glassed or epoxied to plywood underlayment, canvas is not.)

Arabol was used as a lagging adhesive, to coat the lagging on pipes and exhaust systems. It was also used on work boat decks (and this was a really "quick and dirty" method used only on dying boats to wring a few seasons more out of them.) When applied to leaky work boat decks, it was laid down over a yellow colored polypropelene mesh or screening material called "Yellowjacket." It was then painted over with oil based paint. If a wood deck had Arabol on it, the conventional wisdom was it was sure to be full of rot. Whether the Arabol caused the rot or simply covered what rot was there to begin with is anybody's guess.

IF you are going to fasten canvas edges down with staples (as opposed to copper tacks), it is important to use monel staples. Any staple material that corrodes will weaken the cloth and your staples will soon create a "tear on the dotted line" effect.

IF you are going to use canvas and staple the edges down, you'd be well advised to drive your staples into something other than the edge of a sheet of plywood. You want them to hold "first time every time," not just when they feel like it.

IF you are going to drive staples into the edge of plywood deck material, you need to devise a way to make sure those staples won't permit moisture to find its way between the laminations. (I have no idea how this might be accomplished.)

Otherwise, it was a nice article.

[Jay Greer]

I have seen decks that were fastened down in Arabol. Without exception the ones that were made of natural canvas rotted out in a few years. If Arobol is to be used, the deck should be made of synthetic material. Although not to my liking, some even use plastic fly screen. The bottom line is as Bob Cleek so nicely put it, the canvas must remain independent of the surface it covers in order to allow the under surface to expand and contract without cracking the canvas. While this can be accomplished by the use of Irish felt as an underlayment, I prefer white lead as felt does allow the surface to become a bit uneven as well as allowing the canvas to rupture when a hard item or shoe hits it in the wrong way. In addition, white lead will not support rot or mildew spores.
Jay

[John Meachen]

Trakmark adhesive is one of the most tenacious contact glues.It will be a nightmare to remove all traces as it will clog abrasives and severely test your patience with a scraper.Is there nobody with a roll of Trakmark on a shelf in a dusty shed?A complete recovering exercise will be quite an extensive project and May is probably late enough in the year to have an impact on the prospect of getting afloat this year.Good luck and welcome to the forum,from a nearby member.

[ARW123]

Thanks John, that's rather what I was fearing....do you know if it is of the "Evostik" type or epoxy? If the former I know the vestiges can be loosened / removed with petrol. I really don't want to repeat the past errors of Trackmark - or Treadmaster as the modern equivalent.

I was chatting to the chap at "Traditional Boat Supplies" in Beccles the last night - he lays the canvas directly onto a base coat of oil paint & stipples through followed by a couple of coats thinned. Anybody experience this method (not on a Javelin obviously!)?

As for launching this year I have already written that off: I have to modify a trailer, bring her back home, knock a hole in the end wall of a barn to house her, replace a plank, a dozen timbers, make a new hatch cover for the mainsheet well, replace the foredeck planking and forepeak hatch surround, re-deck, strip and revarnish, strip and re antifoul, remodel the berths and cabin arrangement....and that's before I find any other little gems during the process.

[Andrew Craig-Bennett]

In the days of my youth I covered a deck with "Trakmark" and I stuck it down with Bostik type stuff. Might even have been Bostik.

I have also laid canvas decks onto paint.

Yes, use old style mastic behind the quadrant mouldings but be very sure that you have painted the faying edges with a couple of coats of primer first. Otherwise the oil in the mastic migrates straight into the wood.

I am a convert to modern gloop, thanks - either ply and glass cloth and epoxy or Coelan.

[CarlZog]

My experience is limited to one boat, but through it, I have become a strong believer in the traditional white lead paste method.

Adhesives in general seem to cause more trouble than they solve, especially (in this application) when the canvas eventually has to be repaired or replaced.

The "lay it in paint/soak it in paint" methods eventually result in cracking, in my experience.

Carl

[John Meachen]

Trakmark adhesive is the stickier cousin of Evostik and I was unaware that petrol would remove a contact adhesive.I knew that toluene would work but you would be unlikely to find anybody willing to sell you any,and in the event that some could be acquired,you would be doing yourself no good while exposed to it.From the list of other work it would seem as though a good deal of time may elapse before the boat sees rain falling on the deck and testing its integrity.

[stevedwyer]

Is there a reference/resource on how to apply the white lead paste?

[floatingkiwi]

My experience is limited to one boat, but through it, I have become a strong believer in the traditional white lead paste method.

Adhesives in general seem to cause more trouble than they solve, especially (in this application) when the canvas eventually has to be repaired or replaced.

The "lay it in paint/soak it in paint" methods eventually result in cracking, in my experience.

Carl
Yes mate, I agree with the paint thing. I soaked a layer of sacking material wit paint and sandwiched it between le ballast and keelson upon reattaching and , well, you can imagine a thick layer of brittle paint and how well that would keep leaks out. What a crappy idea man. I cut it all out.

[ARW123]

John

I agree, even if I could, I wouldn't go anywhere near toluene! Petrol does soften and remove thin coatings of Evostick (discovered after an unfortunate experiment some years ago).

I think I will play a heat gun over the Trakmark first and pull off with the aid of a wide scraper in the hope that the goo prefers to stick to the underside of the TM and not the planking. Perhaps I will score the TM first into 6" strips with a Stanley knife to make removal more manageable...

Begining to get alarmed at the white lead option with 3 kg costing £35...can't think that that will go too far.

[Andrew Craig-Bennett]

Any self respecting Mate of a chemical tanker nicks a few tons of toluene from any parcel cargo that he carries - wonderful stuff for tank cleaning. (Don't ask me how I know that - and don't ask the UK's Registrar-General of Shipping and Seamen either...;))

If the stuff won't come off any other way, recourse may be had to your second best jack plane and a well sharpened iron - trust me, this works!

The white lead paste bill need not be so very alarming - remember that you will already have got the deck sanded and primed so the surface will be quite smooth.

[seo]

There are old-timey instructions in how to lay down a canvas deck in L.F. Herreshoff's "Sensible Cruising Designs" in the article on building the H-28. I followed those directions when renewing a canvas deck on an H-28, and had good luck with it. One of his prescriptions is to not use glossy paint, because it's slippery, and dries so hard that it cracks the varnish. I used yacht flat paint, and would go to the paint store and have them tint it to a color chip that I picked out of their endless selection. Worked fine.
I have also tried a method of creating a "non-skid" surface by putting on the final coat of paint fairly heavy, with the paint of thick consistency, and while the paint is still wet sprinkle it with epsom salt from a "salt-shaker" can with holes punched in it. The salt causes the paint to wick up around the salt pieces. After the paint is dried the deck is washed with water, the salt dissolves and goes away, leaving a crater of paint. Pretty good traction, and nothing hard in the paint (like silica sand) to make it hard to prep for painting later.
Try it on a scrap to see if you like the effect...
Monel staples aren't hard to find, or terribly expensive. $23 US for 1,000 3/8" staples at Jamestown Distributors.

[seo]

Best way I found to fit the pieces of canvas together is by sewing. I think we used what's called a single felled flat seam, with three rows of stitching. Done by a sailmaker in about ten minutes. If you do it at home with a home machine, I think I'd get sailmaker's dacron thread. It's a lot stronger.

[ARW123]

Joints it seems will not be an issue - I have found a supplier of deck canvas who sells it off a roll 9' wide. My boat has an 8' beam. That's some serendipity for you!!