Making new cockpit coamings

[christopher]

Apart from not being able to remove the existing cockpit coamings, they are a little rotten at the ends. I'm decent in woodworking and have all the tools. If I were to fab new ones, should I use teak planks? The B29 has a pretty mild bend in the board, not more than 8-10 degrees. Whatever material I use, anyone see a problem bending a solid plank to fit the curve?

Here's a somewhat decent shot of the line of the coaming...

[Tim]

No problem with the bend. If you need to, build a little jig using a scissor jack or whatever you have to press the new coamings into position (one at a time).

This was the first one I used, improvised with the jack from my truck.


This dedicated coaming-bending jig that I built many years ago isn't working so well lately and needs to be rebuilt. It's just a cheap scissor jack and some 2x4s. I've modified it a few times for different boats, which is why it's become weak and requires the extra boards and clamps in the center to hold it more or less straight.


Use teak if you want to spend a lot of money, or mahogany at a much lower price (if you plan to keep them varnished).

[christopher]

Very cool! Thanks Tim. I may not have to use the jig as there is a boltup 60% of the way forward of the cockpit at the winchbase. I suppose it might not hurt to put something there just to keep the stress off the fiberglass behind though..

I've seen most fab them with mahogany... How much is a lot of money for the teak ones? I'm early in the goings so the wife is not yet disgusted by the amount of money I spend on this thing :)

thanks!

oh yeah, I may have asked this but what is the appropriate agent to seal the coamings once bolted in? Someone told me "caulking" once but that's pretty generic. I'm guessing I don't just go to the hardware store and buy garden variety tub and sink caulking. I've used siding caulking with great success where a flexible seal is necessary in plumbing projects.

[Tim]

I don't seal mine since I remove them each year for maintenance.

[Hirilondë]

I may not have to use the jig as there is a boltup 60% of the way forward of the cockpit at the winchbase. I suppose it might not hurt to put something there just to keep the stress off the fiberglass behind though..

No matter how you attach them I would use some form of jib to force them into shape. This way there is no strain on the fasteners until they are all in place and can share/distribute the load.

I've seen most fab them with mahogany... How much is a lot of money for the teak ones? I'm early in the goings so the wife is not yet disgusted by the amount of money I spend on this thing :)

Teak is probably around $30.00/board foot now. African Mahogany is about $5.00/board foot or a little more. Teak would definitely promote disgust on your wife's part faster but would require less maintenance.

[christopher]

Okay - yeah i think I can fashion something to put some opposing pressure on them.

@ 30$ a foot I think I'll opt for mahogany. I don't really need to spend 300 some bucks on wood. That's an appreciable percentage of what I paid for the boat.

[Quetzalsailor]

I would suggest less 'inventive' jacks. How about ordinary house-type Lally (actually, the wrong name; I should have said 'adjustable') columns? The concentric thinwall pieces of tubing with multiple holes and crosspins, a threaded jack end and bearing plates. I have a bunch of cheepies with rolled threads and one older good one that has square threads and a thrust bearing. When jacking the house, I'll use two side by side and advance each alternately. Presuming you control those crosspins, they're not prone to causing embarrassment or undue excitement.

I think you ought to give yourself a little more thickness to account for material loss over time due to weathering or successive wooding and finishing. I think Quetzals' were closer to 7/8" when new; they're less than 3/4" in places after 40 years. I think that, if there is any sort of significant force to be used, I'd build a jig and avoid stressing the boat. Ditto if the board is unwilling to make the bend, I'd steam it. The curve is usually more toward one end. Simply shoving in the middle of a stick will give you a parabola, not a semi-circle or other curve which continues to the end. (That's why brick arches on houses built by unknowing carpenters and masons are flatter at the ends and more curved in the middle.) Means that your jig has to be more curved at the end to compensate for the board's natural unwillingness.

Wood choice is a matter to be decided by taste and pocketbook. Teak and Hondouras Mahogany are now 'protected' woods and thus good stuff is expensive. Plantation Teak is, in my experience, not as dense or pretty; it does not even smell like Teak. Less oil, I suppose. It's the same species but not grown in the same part of the world, and not to a natural density or age. However http://www.fpl.fs.fed.us/documnts/pdf2001/willi01d.pdf is a US government document which seems to say otherwise, perhaps paid for by Bolivia.

[bcooke]

I don't really need to spend 300 some bucks on wood. That's an appreciable percentage of what I paid for the boat.

The boat was cheap because it needs a lot of $300 pieces of wood. You pay up front or you pay in the end but either way you always pay. Someday teak coamings will seem like a cheap upgrade...