coaming replacement - wide boards

[rwsouthwick]

I'm having real trouble finding mahogony the right size to replace the rotted coamings on commander #179. I need about 14" of width at the widest point, and nearly 11' of length. My local yard can mill a couple of boards to this size, but at nearly $15 a foot all in :eek: (I'm in SF).

Another option is to get narrower boards and glue them together to get the necessary width. Has anybody done this? Opinions about strength, durability, looks, and where the joint should be?

thanks,

-- R

[Bill]

I did not "do it," but the coaming boards on #76 are made from two pieces of teak.

[ebb]

Mahogany comes wide, should not have any trouble finding it. McBeath, Hand Loggers, Mt Storm. Not cheap any more, especially Honduras, what you are looking for. Wide or narrow it's the same price, for 12 footers. But one never knows. Maybe find a deal. Just bought some teak & mahogany - they were the same price. About $15.

I've seen three Ariels (mine included) with the coaming split at the aft end in one piece original installations. Since the aft end is not supported it could easily get cracked by a foot or something. The front is supported by the rounded block (and the winch pad/block) on the Ariel - haven't seen a crack there in one piece boards. I would create a small block like the front one to support the aft end. Help keep the refit healthy.

Could possibly make an arguement that coamings glued together in strips butcher block style would make a stronger piece. Might be less likely to warp. Don't think mahogany is very warpable - it's stable. The other problem with glueing exposed wood is the glue line. Resorcinol makes a black line, gorilla glue has problems, brown glue is not really exterior, yellow #2, don't think I'ld trust my coamings to it, epoxy is out of the question. Just kidding about butcherblock coamings! Under 6-8 coats of varnish (LeTonkinois) thin black glue lines (Cascophen resorcinol) aren't really noticeable anymore under the amber bling.

If the lumber comes from the same tree, glueing up would not be too noticeable paying attention to the grain. Personally I would avoid it - it's more work and the result probably disappointing. Coamings will be looked at, I would spring for the full monty. Also find port and starboard boards from 'the same tree'. Same color and density. As much vertical grain as possible. Slab sawn is sometimes cheaper. You can find book matched boards at yards that sell to furniture makers. Or get an 8/4 piece and have it resawn. It is also possible to make a deal on bent pieces, which isn't what a tabletop guy wants. But you can pass them thru the planer and sander just fine. Coamings are 7' long, about 11" high, and at least 3/4" wide, wider is much preferred, like 7/8s. A single board 15-16' cut in half insures the coamings under varnish are familiar with each other. 8' boards at the yard may be easier to find. Sometimes Honduras is cut, rough milled, dried and shipped to the yard in 'log' form. It is possible to find 'butterfly/bookmatch' pieces in the stack. It would then be possible to have coamings with matching grain pattern on both sides with the same match as to light reflecting off the varnish.

The bigger the lumber yard, the better the deal. And selection. Good luck!

[rwsouthwick]

Thanks for the tips -- I found some 14" wide boards at Van Arsdale, at about $100 a board, so no gluing, which I agree would have been a pain.

-- R

[ebb]

Fantastic!

Got spar spruce from them a 100 years ago.
And close-grain air dry redwood, purple as a plum.
And later, making decks, patio grade alaskan yellow cedar,
which never raises a splinter - some culls of mostly clear
I hope to mill and put in a bit of ceiling in 338.

[Scott Galloway]

The coaming boards on Ariel hull #330 were replaced by a previous owner with teak. The boards are single piece teak boards. Although they had been grey for some time and were growing lichen when I adopted my boat, they cleaned up nicely with a two part stripper and remain in fine shape with the use of Semco Teak Sealer, which also seems to work satisfactorily on the remaining mahogany hatch trim. I have done some other projects with teak. (I replaced the hand rails, replaced the hatch cover trim piece added a handle to the hatch trim piece, added boarding steps, and built pin rails). My Local lumber company stocks teak various lenghths and widths in one and two inch teak. If I had to do it again, I would use teak.

[ebb]

'Lo Scott,
Teak is the best, no compare.

What's your lumber yard down there?

[Theis]

I like the mahogany over the exterior teak - hands down. But teak looks nice on the inside, as long as it is oiled

But one other issue about laminating two boards - although your issue appears resolved. The glue line is most likely where rot will occur. On my coamings, where the big block at the forward end joins the boards is where the rot started and then went into the mahogany. For outside stuff, wher strentght is not an issue, use single boards. Forget gluing two together.

[willie]

Hey, while we're on the subject....
Working on 5th coat of epifanes, fun fun fun. But worth it. Wow, do they look nice. Guess i was lucky, my wood is in great shape, coamings one piece mahogany. So a couple questions, which are pretty minor, but still questions.
Do i need to sand between coats now? It makes it easier to see where you have new varnish, but takes time ya know...
Also, need some wood plugs for the bolt and screw holes. Guess i just need to dig around and find a supplier, unless someone knows of one? Looks like 7 1/2'' for each side, and 3 approx. 3/8'' for the screw holes to the winch pads. (X2)Don't really want to buy them in bags of 50 or 100...

Also, when putting them back on, i guess the smart thing would be to put the sealer on the boat, then position the boards? Wondering how to go about it without making a mess on my new varnish!

Also have some sunbrella on the way for making some covers. Still looking for thread????Has anyone used velcro for holding them on? Don't really like the idea of snaps everywhere....

Also need to repair my main, must have pulled a little hard on the outhaul, as it has a tear on one side at the clew. It's several layers thick there, and still wondering what to do with it. Any experts in sail repair, help!

Guess that's about it for my current projects. Wish i had her back together, we'd go sailing! Nice monsoon here in the nw. :cool:

[dasein668]

Just bought some teak & mahogany - they were the same price. About $15.

Well compared to our prices here in Maine that teak is a steal, but the mahogany is about triple! 4/4 Honduras Mahogany is about 5.50 a b/f. When I replaced my coamings (I bought 12 foot boards, 14 inches wide, 4/4) the total was about 150.

Just picked up a board that was 17 feet by 6/4 by 10 or 11 inches wide (!! that's a big board!) which I'll be ripping down for my new toerail, and the price was 6.57/bf. We are lucky up here to have a really great hardwood dealer who caters to the boatbuilding trade, so I'm sure that helps especially with wide boards.

Teak, on the other hand, was running about 24 bucks a board foot last time I looked. OUCH! :eek:

[ebb]

oh gee Bill, buy a bag or two, drill a few more holes.
What are they $2, $3 a 100? They're nice to have around, great conversation starters.
.................................................. .................................................. ....

Sealer?
Bedding compound, rubber goop? Put it on both surfaces evenly with a spatula, use too much you will have a lot of squeeze out.

Probably the best way for the first timer is to circle each screw hole with a bead - and run another bead across the top at deck level. If you are using Dolphinite cut the squeeze out off when a sets up.

With D. you can experiment. Spread it on, try the pieces, take it off, add some, scrape some off, put it back on, take it off, etc, til you get it right. Try that with Lifecaulk!

If you insist on glueing, you are on your own. Try to find a solvent that won't remove the nice varnish. If you are using clear rubber, you let it set and cut it off.
.................................................. .................................................. ....

You can get a special UV treated thread at a price that will last as long as Sunbrella, which is saying a lot. Normal polyester thread will fry in a couple years.

Cruisers have peel and stick repair patches for emergencys. Maybe you can add some round stitching with a needle and palm and some more of the special treated thread!

If I didn't have the special thread, I would find the waxed thread used for whipping, comes in tidy kits with mansized needles, and the palm, not to forget the palm, that's what I would do. Of course.

[tcoolidge]

Sailrite.com has everything you could ever want or need to make or repair sails. Prices were relatively sane last time I dealt with them. I might be able to find an unused small spool of sturdy sail thread around here somewhere if you don't need a lot. Hand sewing is easy but the stuff is hard on machines that aren't made for heavy stiff thread.
Tom

[ebb]

Lo there Dasein,
That's incredible mahogany prices. Wonder what direct connection you guys hsve with Central Am up there. I'ld look around for the best stuff, buy a quantity, and store it like an investment. Real Honduras (so we hear) is becoming as rare as real teak.

I'm with Theis on mahogany for the exterior. Am I correct in thinking that Ariels originally came with M. coamings? That could influence my choice. And which method of harvesting is less destructive of the forest each wood comes from. I don't think there IS a difference any more.

We suppose that Honduras mahogany comes from plantation grown trees. That may explain the price difference. Plantation teak is so obvious a different wood than 'old' growth eveybody can recognize it. Wouldn't you think the widest boards are from old growth and therefor have the preservative and lasting qualities needed for boats.

Teak and mahogany are a dream to work with. They can't be characterized as 'hard' wood. Modern carbide tools make it very easy to shape these two.
Finishing very easy too.

Environmental alternatives might include locust, yellow cedar, port orford cedar (I have heard that the Canadians have a third world attitude about their marketable stands of cedar, etc.), old growth cypress, southern cypress, yellow pine. The super hard woods (packing crate) comiing out of Australia: jarrah, marranti, what's that great stuff Geoff is using?

Teak hardly moves once you get it in place. Mahogany moves some. When you put the coamings into the rabbet of the front coaming block, where any piece is touching another part, to help avoid rot down the line, BED all pieces! Try to keep sweet water out of the joints. Drive the screws in wth something too. There is good arguement to completely cover the pieces first (ie, befor they are put together) with thinned low viscosity epoxy or CPES. Then put your favorite finish on after assembly.

Sorry, don't know why I get into this......................... :confused:

[dasein668]

Not sure if the stuff is plantation grown or not. I do know that it is generally nice dense stuff with pretty straight grain and generally runs close in price to cherry.

I buy from these guys: Maine Coast Lumber (http://www.mainecoastlumber.com/) Great prices, quality inventory at the local shop, reasonable delivery, and generally excellent quality wood.

When I built my new coamings I replaced the end blocks as well and they are now an integral part of the coaming itself.

http://www.dasein668.com/art/projects/coamings/varnish01.jpg

The replacement of the coamings is detailed here: Coaming Replacement (http://www.dasein668.com/proj/ext/coamings.shtml)

[commanderpete]

Nice work Nathan.

I wonder if Teak or Genuine Mahogany is a stiffer wood than the Philipine Mahogany that Pearson used.

Is there a way to "relax" the wood by slowly bending it over time before you varnish and install it?

The coaming boards need to bend quite a bit on the Commander

[dasein668]

Hi Pete,

It doesn't look like your Commander has any more curve/bend to the coamings than on my Triton. I didn't really have any trouble getting the boards to conform to the shape. I used a jack the first time, but they have been off the boat every year since, and I've had no trouble pulling them tight just with screws. I start in the middle of the board and bend it as far as I can (usually leaving just a small gap) with my knee while I drive the first screw. Tightens right up with no problem.

[ebb]

Aside from suspending boards at ends with weight in middle.

Have a flat wood surface, or metal table? Could bend the uncut boards, full width, using shelf supports screwed to the table in a fair curve smaller than the curve needed. Start clamping, using the deepest throat clamps around and full width vertical pieces under the clamp against the mahogany. Screw the clamp in a little more as resistence lessens. Leave it for awhile in clamps, days, weeks.

If you faircurve a bend in longer wood than what you want for the coamings, like a couple feet, I'ld guess you'ld be more likely not to get the straight runoff on the ends that Nathan mentions. You'ld waste the end pieces (good bread boards) but you'll have curve running past the ends so to speak when you cut the pattern. Probably get better results in a warm room.

.................................................. .................................................. ....

Haven't done this:
Same clamp mold as above and in a warm shop. Mist with water, heat with heat gun - creating steam. Do this to both sides. Jackson Pollock ballet. You might get the plank to relax this way. If you can remove the clamps and lock the wood in with more shelf standards that would be good too, I think. Use wood cleats between work and metal. Especially after you do your first steaming and see if anything has happened by taking it out of clamps. If the chord looks permanent, you could put it back, spray and heat some more, lock it in with all shelf supports. Steam some more.

.................................................. .................................................. ....

Build a steam box out of cheap exterior plywood and galv grabbers just big enough to house both planks, stickered, separated. Using campstove, or electric plate if indoors, and water in a gas can, attach nozzle with hose and some kind or plumbing fitting to one end of box. Make it removable, as in Lid. This will really get hot. The box won't. much. Never tried this: but wrapping that 6" wide shrinkwrap around the box might seal off everything until the job is done (water comes out everywhere.) - two, three hours? You need an exit hole too out the far end which you have tilted a bit to get runoff, you can stuff with rags. See Roy Underhill, Yankee Woodshop.

You really can't put both pieces in the same mold, so maybe you decide to do them separately. Steam one board at a time. Your temporary set up has to last that much longer. Now, the classic fire drill. When you think it's cooked (the plank good and hot clear thru) use oven mits and throw it into the clamping mold as quickly as you can. Quicker. You have all your pieces ready to go: clamps, cleats - you hopefully will be real surprised how easily it bends. Hold that bend at the deepest with a clamp as you force the plank flat on its edge to the table. Now clamp from the middle out to the ends, fast. Make adjustments after it's in the form.

When we did it an age ago, we included a try piece in the steamer we could pull out and test. We got hot 2 X 2 white oak to wiggle when we shook it!
I can't attest to water stains on mahogany. I haven't bent M. nor a wide plank. I think steam time was one inch an hour but a wide plank might take a little longer. Generally clamping pressure is modest. Don't want to distort the wood under the clamp. Or in the mold. Eye the piece to see if the curve is fair.

If the mahogany keeps the overcurve once you release it, that's a plus for installing. You may want to keep it in the form, loose, til you work on it.
Most wood favors a side it would want to bend on. You can tell by sighting its length on edge which way it'll be more comfortable. The curve shows up.
Once cooked long teak rails in a steamer (sort of successfully). Had to take the pieces out to reverse them, as the steam didn't keep all its hot down to the far end. It's really a gas!

In terms of steambending, the curve of the coaming is very very modest. Once you get them bent, store them bent. Good luck.

PS. Just occured to me that somebody might try a flat mold. Both coamings could be done same time, by screwing cleats of graduated heights to the table that would make that nice fair curve (a little tighter and a little longer) you'ld bend the planks over the rack, securing the ends. Then pour boiling water over all. Lots. Any tendancy for the work to raise, screw a cleat down over it into the cleat under. I think you'll get better results bending full planks before shaping. I would get the thickness close, tho. Think it might work?

[ebb]

New work or 'wooded down' -
Pretreating the wood befor assembly with thinned epoxy is IMCO the best rot preventative. There isn't much penetration of any liquid into the pores, but 2-part epoxy does help protect the wood better than plain varnish or alternatives that sit on the surface. Use the epoxy to prepare the varnishing surface by sanding between thin coats. If you get the pores filled at this stage the finish will come out like glass. With less coats.

If the varnish has UV inhibitors in it that will help the epoxy last as the weather degrades the surface between maintenances. Maybe avoid wooding down all together.

Epoxy is very good at protecting end grain where there is some penetration.

[Theis]

A word of caution about using epoxy on wood. It will keep the wood from breathing. Any condensation on the inside or existing moisture will not be able to evaporate. If that happens the wood will either rot or the portion will pop off. This is a particular problem in these cold climates where we experience that white stuff and our boats are on skids six months of the year.

[ebb]

Talking about, in this application, epoxy used as a primer.

Exposed epoxy by itself as a finish could be a problem where it has been built up as a coating. Putting a boat up wet might create a raft of other problems. The boat should not be closed up but have air moving through at all times. Constant fresh water damp will get through ANY finish.

If you are worried about you own mix of thinned epoxy, buy CPES which is formulated to be flexible (ie, work with the wood.) You can't build up with this stuff - if you try it will get gummy. Also, you need warmth for CPES to go off properly. It has been known to blush. CPES is made with some bad solvents, that's why I don't use it any more, I used to bathe in it. "Penetration" into sound wood is a myth. Well: microns more. that's what 'protects' the wood surface. But it will stick better than the finish.

Therefor make your own up from 100% solids low viscosity laminating resin with slow hardener adding a small amount of xylene. Each man's epoxy is probably different. Each man's climate situation, different. Each man's method of application, prep, materials. Each man's lay up facility. Too many varibles.

If you insist on varnishing your exterior teak or mahogany, your finish is better off on a (thin) primer base of 2-part epoxy. And your maintenance of the film must be impecable. You probably shouldn't cover a boat, whose woodwork suffers from the last season's wear, without a new coat of varnish.

If the thinned epoxy is sticking to the wood, and you fine sand the cured epoxied surface in prep for the varnish, then your varnish will stick to the surface better than it'll stick to plain wood. You are looking at wood here with something thin soaked in on it - not a coating of something on top of it like the varnish will be. The varnish will be less likely to pull away from the wood. I'm sure the wood will breathe when it has to.

However, 20 coats of varnish may make wood unbreathable.


[The way I understand it, for what it's worth, the finish job will last as long as you keep the sun and weather from getting to the surface of the mahogany. UV inhibitor(s) in the film is the only way to go. With regular light sanding and touch up coats. Keeping the tops of the coaming boards and hand rails shiney. I sure didn't invent this epoxy primer business. So far as I know it is accepted practice. Don't know what the first steps are for systems like Epiphanies or Bristol. The above works for traditional 'soft' varnishes: spar varnish. Helps the finish last longer. I find 'wooding down' failed or tired coatings very disagreeable.]

[Stephan]

Coaming Repair -

My coaming boards are both cracked about half way from the stern end. They are still holding together, but I'm worried that if I don't try fixing them they will only get worse and completely break sooner or later. What to do? Simply put glue (Gorilla glue?) into to crack and somehow press them together?

[Bill]

A possible fix:

A previous owner ("PO") attached brass plates at each end of the coamings on Maika'i. (Approx 1" by 6" fwd and 1" by 3" aft, if I remember correctly.) They support (in my case) the two boards that make up the coaming assembly. I'll take photos next time I'm at the boat.