Fiberglassing wood masts

[San Juan Sailor]

Greetings,
I'm a new member. I recently bought a Mariner 32 as a project. Has anyone had any experience or have any opinions about fiber glassing wood masts? I'm considering this as a way to add strength and maybe reduce maintenance. I'd varnish over the glass and epoxy. I also have a San Juan 24 that I restored seven yrs. ago.

[imagine2frolic]

I can't tell you yes, or no. My boat is wood with a skin of glass on it. I don't see any difference. One problem being adding weight?

[AnchorageGuy]

Aside from the additional weight, you will not be able to assure moisture can not get in through hardware fasteners, etc. and now you have trapped it inside the wood and rot will accelerate. Not a good idea, IMO but many do seal wood masts with epoxy.

[Steve Rust]

I agree with Chuck here. I don't see how fiberglassing a mast would add enough strength to make it worthwhile without it being to thick and heavy. Epoxy coated and then varnished for UV protection might be worthwhile. You can drill the fastener holes oversize, seal with thin straight epoxy, and then fill with epoxy thickened with high density filler. Tap the new holes in the epoxy and use course thread machine bolts/screws for fasteners. Do not paint it, you want to be able to see what is going on under the finish.

[Pblais]

With a wood mast you need to "see the wood" to get a better idea of how it's doing. It may be the one advantage to a wood mast. Covering it won't really change the structural value of it and the wood still will flex and expand and contract just like it always has. The fiberglass just gets in the way of the wood.

[Boracay]

If your mast is engineered in the normal manner then the wood part is going to be under compression and (of course) the wire and rope part will be under tension.

The mast may flex or bend to some extent so it is possible that some things that you do may be detrimental.

Fibreglassing may carry the risk that the slight flexing of the mast could cause it to delaminate allowing fresh water to reach bare wood.

Past a good slightly flexible surface protective coating, ensuring that all components are in good condition and properly mounted and checking that water cannot pool anywhere it is hard to think of anything that you can do to "improve" your mast.

[David M]

Wood and fiberglass have two different rates of flex. Wood swells with moisture and fiberglass does not. I think you would be asking for delamination problems.

[Wotname]

Hmm... quite a few opinions here.... let me add mine.

The mast is under compression staticly, but when it bends, one side is compressed and the side is under tension.

Epoxy is good in compression but not so good in tension however glass is very good in tension.

Would I epoxy and glass a wooden mast? Probably not as I would be worried about the weight aloft (especially considering its moment arm). I am assuming the scantling of the wooden mast was sufficient to begin with.

Would I epoxy it (without glass)? Maybe if I was sure that I could truly encapsulate the wood COMPLETELY with epoxy, i.e. no surface to be left uncoated and all fixing treated as per Steve Rust's post.

When encapsulated, the moisture content of the wood remains the same as the day it was when it was encapsulated. So make sure it was DRY when it was epoxied. Typically less than 12% moisture. Doing this will ensure the strength of the mast will be optimium.

However, it ANY surface is not epoxy coated, then the moisture content of the wood will vary and also the wood will shrink and expand accordingly. IMO there is no advantage in using epoxy on the mast UNLESS it is encapsulated completely.

BTW, even encapsulated wood will shrink and expand slightly due to normal thermal conditions as would any other material. An epoxy designed for timber will have a similar coefficient of expansion as timber. This is quite different from the shrinkage and expansion on timber due to moisture content.

[rebel heart]

I have my wooden mast off the boat undergoing some repairs at the moment. I don't agree with the "you have to be able to see the wood" statement. That implies you need to have it varnished, and not painted, and plenty of painted wood masts are happily keeping the rigging alive and well.

Rotten patches are pretty easy to spot even through paint; you'll see the paint blistering and peeling much the same as you'd see the black rot in the natural wood. Beyond that, plenty of varnished masts are painted at the mast head, which is one of the most common places (that and at the spreaders) to get rot. And the same vigilance that will have examining your mast with a tap-tap sounding out for hollows you would need to do for a varnished stick anyway.

Previously our stick was varnished, and it was a maintenance nightmare. You have to have *a lot* of time at your disposal. You can't just pick a day and varnish, because the wind might be too high and you'll splatter your cabin top with the stuff from 50' above.

And again, even with the varnish, the only way to really detect rot was to go aloft and tap around, which works the same for paint. If you have fifty feet of good wood, and six inches of bad wood, the bad stuff will stand out like a sore thumb, regardless of paint or varnish.

I wouldn't fiberglass either; there are a lot of smart wooden-boat-people involved with my mast right now, and the idea of fiberglassing to them is crazy talk.

I'm epoxying and painting mine, which will make it much more resistant to rot and topical damage, but not quite so sealed in that it's unrepairable at a later time if need be.

Another good move with epoxy is that (this might just be my belief) it stops and / or slows down termites. They come in via tiny little rot cracks, or any opening where they can get a foothold. If the stick is *fully* epoxied and painted, you're set. The same should be true for raw wood and a varnish, but even the best varnish is likely to have a few flakes here and there, especially near fittings, which is where rot (and termites) like to pop up. That same area would be epoxied, if the wood was treated as such.

[Amgine]

Epoxy is not generally the first choice for an external finish due to its sensitivity to sun, as well as the many other issues noted above.

I *do* politely disagree with Rebel Heart regarding paint vs varnish. Sun damage and water damage other than rot, as well as termites, do not show up under paint, but they do show up under varnish. That said, the upper third of my mast was painted and I never even considered stripping it off.

[Wotname]

Originally Posted by Amgine

Epoxy is not generally the first choice for an external finish due to its sensitivity to sun, as well as the many other issues noted above.......

If you are referring to epoxy as a clear finish coat then I have to agree totally; however as a first coat on exterior wood, epoxy is king - providing the other sides are also epoxy coated and all exterior surfaces have sufficent top coats to provide UV protection - IMHO.

[San Juan Sailor]

I guess the consensus is that glassing masts is not a good idea.

On the subject of bright or painted, personally I want to see what's going on under the finish and I like the look of wood. I think sealing with epoxy before varnishing helps in the long run. That's been my experience on other wood I've treated that way over the years. Of course many coats of varnish helps. Wood= maintenance, no way around it. I'm thinking full boat cover.
Dan

[jaga]

Couple of comments:
First, I just finished re-varnishing my mizzen with 10 coats of varnish. It's a lot of work when needed, but worth it. Ongoing, however, you can quickly add an additional coat once or twice a year by simply scotchbrighting on the way up, and varnishing on the way down. I have a lot of wooden boat friends that do that routinely, and can keep a major refinishing at bay for a good while. Frequency will depend mostly on your climate.

Second, my main and mizzen are originals (old growth spruce) on a 53 year old boat, and in excellent shape. Well maintained they can last a long, long, time. They're not painted for the very reasons mentioned above, though when I head back to the south pacific I may paint the upper 10' or so, just to ease maintenance.

Where in the islands are you? I'm anchored in Roche right now, just off the customs dock.

Scot

[Amgine]

Sweet design, Jaga! Where was your boat built?

The best part of the painted top of my mast was night sailing: it was much easier to see the top of the mast with the white paint.

My boat is currently on the hard in Anacortes, Fidalgo Island. I was hoping it would be going back in today or tomorrow, but things are taking longer getting a new shaft milled.

Are you anchored east of the marina? I love Roche Harbor, great restaurant, but it does get a bit expensive on the dock. I think I've only stayed on the dock during winter rates, and those won't kick in for a couple more weeks yet.

[jaga]

Originally Posted by Amgine

Sweet design, Jaga! Where was your boat built?

The best part of the painted top of my mast was night sailing: it was much easier to see the top of the mast with the white paint.

My boat is currently on the hard in Anacortes, Fidalgo Island. I was hoping it would be going back in today or tomorrow, but things are taking longer getting a new shaft milled.

Are you anchored east of the marina? I love Roche Harbor, great restaurant, but it does get a bit expensive on the dock. I think I've only stayed on the dock during winter rates, and those won't kick in for a couple more weeks yet.

Built in Vancouver in 1955, but she's not a 'pure' Ingrid as the scantlings were 'updated' by Laurent Giles (a personal friend of the original owner/builder), so with an Atkin/Giles design she has quite a pedigree...

I'm about 200 ft square off the customs dock/marina office, right off the marina. I think that works out to northwest. Been stuck here all summer waiting for a new engine, so it's been a bummer of a summer sailing wise. Had nothing to do so I stripped and revarnished the mizzen with it standing. That's been interesting, but made a good show for many of the 'yachts' passing by. Should have charged admission for watching while I hang off the mast with a varnish bucket - could have bought a lot of beer

I'm actually sitting up close waiting for the marina to open for the winter moorage, but will haul out in November for the repower at Jensens in Friday. I'll have to get a tow down there. When the engine's in I'll be back to Roche for the rest of the winter.

If you have a chance read Jaga's history on my website. There's lot's more I can't put in print since the principles are still around...

Scot