Planking and epoxy

[F.H.B.]

Well, there seems to be a lot of different opinions out there about the old fashioned strip planking (carvel) and adding epoxy. Studies show that moisture in the form of vapor does get in to any wood even when coated with lots of layers of epoxy. It takes about a year to do so instead of a few hours, but going to the tropics for a year or more then to the hard some place dry, there will be expansion and contraction.

So, I am looking for a way to save money over buying plywood and gobs of epoxy (Sue me ) yet still having a low mainenance boat that does not look too ugly (IE planks on a diagonal showing through the finish would be a ugly). Planking flat sides and bottom with two layers of dimensional lumber saves about 66% material costs over equivelent thickness of plywood. Now factor in the several $k of time and epoxy for of those layers of plywood and strip planking looks mighty good. Strip planking is a KNOWN factor of hundreds of years! I just don't want to mess with caulking, rot, etc.

So, I ask, since I can't find a book that combines strip planking with epoxy coating, "what is the method for this?" Should I be planning to coat every plank with epoxy and letting it cure up before adding the plank to the hull? Can I just epoxy bond raw wood planks to raw wood frames then after adding fillets (are these even needed?) just paint inside and out with a couple of layers of 2-part epoxy paint that has been proven to be as effective as epoxy coating in the studies? Can I still use nails or is that a no-no under epoxy? Do I need fiberglass inside and out over planks or will just epoxy paint do, (since Buehler says it goes on plywood because ply crazes and checks)?

Anyone want to chime in on planking with 2x12 and 1x12 and epoxy on flat sides and bottom? Surely someone has done this and has some tips?

Thanks!
- John

[PAR]

You know, it sounds like you've read a couple of books, probably older and not especially current ones at that and now you think you're armed with the information necessary. One of these books has to be Buehler's boatbuilding thing.

a couple of layers of 2-part epoxy paint that has been proven to be as effective as epoxy coating

You're kidding right? I don't know of a single test that would suggest this is even remotely true. I don't know where you heard or read this, but try to avoid these places in the future, as they are grossly incorrect.

since I can't find a book that combines strip planking with epoxy coating

You're kidding again right? Have you found any books about strip planking? Strip planking is a general term for several distinctly different building methods. I can think of at least a dozen different strip plank methods, most of them require 'glass sheathings of some sort.

Studies show that moisture in the form of vapor does get in to any wood even when coated with lots of layers of epoxy. It takes about a year to do so instead of a few hours, but going to the tropics for a year or more then to the hard some place dry, there will be expansion and contraction.

Do you understand what you're reading about moisture vapor penetration? Look the simple truth is, for all practical purposes, if a piece of wood is properly epoxy encapsulated, it becomes moisture stable and does NOT move with changes in moisture content. Again, I'm not sure if you're reading this stuff, hearing this stuff or just reading too much into things, but epoxy has revolutionized several industries, with it's ability to resit moisture and maintain it's grip on something.

I can go on and on with the above post, but since you seem to be fairly new at this and also on this forum, I'll be nice.

As for your 2x12 or 1x12 planking schedule, this is sounding an awful lot like Buehler again. 2x12's epoxyed together will not work, but 1x12's will, though I have no idea where you'll get reasonable vertical grained 1x12's without selling your sister for a few years. Secondly, you'll need a developed hull shape, that will permit these wide planks. Or you could double plank which is fairly common, but does require some real boatbuilding skills. In short, do what the plans say, unless you're capable of engineering the scantlings differently.

Maybe it would be easier, if you asked what you wanted and stated what you'd like to do, because at this point, your knowledge of the methods, materials, physical properties and design aspects are lacking, or are sufficiently ill informed that making reasonable decisions about your choices will be most difficult.

Let's start with which set of plans you would like to work from.

[F.H.B.]

Gotta start somewhere, Par. Remember that you were new at things at one time too and there were less technologies and techniques to familiarize yourself with back then.

Here is the study, http://www.fpl.fs.fed.us/documnts/pdf1987/feist87a.pdf and you are correct that it is vapor based. Since our boat will go to many climates for years at a time in each one, we wanted to make sure we are going to keep dimensional stability. After all, if the only consideration is keeping liquid water out, hundreds of years of knowledge is available.

No plans. We can't find what we want so figure the next best on a limited income is to use "design it yourself" books. A dory or other "flattie" is what we are after for a lot of reasons I won't go in to. Suffice it to say that we like them and it suits our purpose.

There is a lot of info on strip planking on the 'net, but I can't find anything for large boats regarding whether I need to coat each plank with epoxy first, how heavy of glass to use, do I need glass on the inside too, whether I still need fillets, etc. To me, this should be easy. After all, strip planking has been used for at least two centuries. All I am doing is protecting the wood with epoxy, but I want to do that right. What book do you recommend for strip planking with epoxy on a large boat?

[Steve W]

You seem to be confusing carvel planking with strip planking,they are two different things,which are you considering using?If you are looking for a dory type hull there are plenty of plans available,try Jay Benford, Bolger and Reul Parker for a start,you should not design your own boat until you have accumulated a lot of boatbuilding or sailing experience. Strip planking dosnt make sense for the type of boat you want,plywood does as does carvel planking.Why dont you narrow down the design brief for us and maybe someone can steer you toward a suitable existing design which will then make the construction method decision for you.
Steve.

[F.H.B.]

What we are after is the ease and low cost of carvel planking but the potection of epoxy. This is why it seems I am confusing the two terms. I have quite a bit of sailing experience and an engineering background. The scantlings aren't the problem so much as the technique for applying the planks. Scantling wise, we need 2.25" of planking.

We'd like a 48' motor sailer. We like how fast and inexpensive to build the Bolger advanced sharpies are and we like the Benford dories. The expense of building up layers of ply is getting to us, however, and we can't find the technique for using planks and epoxy. The scantlings are easy to find in many books, but the technique isn't. If we did a sharpie design, I would think that very wide planks could be used to make planking go quickly. But, do we need to coat each plank with epoxy first? Do we use fillets? Do we need fiberglass inside and out?

Does this help?

Thanks so much!

[sabahcat]

Heres a good start for you

Very good book, not overly technical, easily understood pictures and there is no bamboozlement with useless information

http://boatcraft.com.au/simpson.html

http://boatcraft.com.au/SimpsonBuilding.html

[TollyWally]

I've read Buehler's books a few times and have never got the impression he would recomend anything along the lines of what's been described. He favours things simple, cheap, and hell for stout but this scheme isn't his. It would take a misinterpretation of epic proportions to come away with this idea from reading his work.

FHB,
I say this without malice. it is obvious from your postings you are unaquainted with some of the elementary charactoristics of wood as a building material. Do yourself a huge favor and build a dinghy to be used by the "mothership" first. You will need one anyhow and will have a much firmer grasp of wood by the time you have researched and built your little skiff.

Best of luck.

[PAR]

How could you possibly know what the planking thickness should be? First of all, 2.25" of planking is ridiculously thick in most applications. Coming from an "engineering background" you should know better then to make such grand assumsions.

I'm not sure what engineering background you have, but very wide planks cause a whole host of issues, assuming you can even find suitable planking widths. Not even George Buehler would do this, though 2.25" thick planks would be just his style.

The "sealed up hull" (a commonly referred to stage of the build, where the hull is built and the decks are on) will take about 10% to 12% of the build effort on a 48' motorsailor. This is actually a fairly liberal estimate, it'll likely be closer to 8%. So, the economies you are attempting to employ in the hull build, to save, costs, effort and time are not only ill advised, but not going to make much of a dent in the big picture of the project.

More then anything you need a professional to design a 48' yacht for you. The other two options are a stock plan or a semi custom plan (a modified stock plan). Of course then you build to the plan. This is the most economical way to build 48' yachts. Screwing around with methods, techniques and scantlings you don't comprehend are sure fire ways of ending up on the evening news on launch day, assuming you ever complete the project.

Thee is nothing fast about building 48' motorsailors, regardless if designed by Bolger or me. For what it's worth, plywood is the widest planks you can get. It's much more stable, it's not prone to check, split or have internal stresses, like solid limber is. For a sharpie style hull, particularly a 48' one, plywood, if not steel or aluminum would be a far superior choice then solid lumber planking. A quick look of the physical properties (general engineering work) of plywood, will bear this out, which makes me wonder what type of engineering background did you come from. Railroad engineer?

http://woodenboat.com/forum/showthre...ght=architects This thread (read the whole thing if you want a good laugh) is a clear and classic example what happens when someone who isn't qualified designs or makes major modifications to a boat (both where done in this case).

[sabahcat]

Originally Posted by PAR

How could you possibly know what the planking thickness should be? First of all, 2.25" of planking is ridiculously thick in most applications.

Holy ****, 62mm thick planks

Are there enough trees left in the world to build a boat of those epic proportions?

[sabahcat]

Originally Posted by TollyWally

Do yourself a huge favor and build a dinghy to be used by the "mothership" first. You will need one anyhow and will have a much firmer grasp of wood by the time you have researched and built your little skiff.

Best of luck.

But look at doing it out of 6mm and 4mm ply instead of 12 mm and 25mm

[TeddyDiver]

Originally Posted by F.H.B.

No plans. We can't find what we want so figure the next best on a limited income is to use "design it yourself" books.

The amount of funds for a "design it yourself" library is not too far from a deasent stock plans. About 1m/3' of book shelf of boat building/design books.. it's some 10000 pages to comprehend sometimes a bit contradictive information..
The most important factor to DIY design is that you don't find any meeting you desires, and then you got to príority the most essential of them and have a trade offs with the rest.. but for sure yuo can't have them all in a single boat.. never. Unless you really don't have any more specific desires than 48' motorsailor, and in that case you can just buy any plans fullfilling that description. And by the way, a 33 auxiliary sailboat might be even better for you. You just don't know it...
And if you don't know what you really need you can aswell buy the cheapest boat you find and start sailing.

[F.H.B.]

Thanks for the pointers. We keep looking for existing boats and I have been on a lot of different designs. I fed the info you all provided here and other posts to the wife. The wife wants a certain layout so that made the size.

So far, the best bet for us in terms of space and ability to lay out how we want was a motor sailor named Lady Emily. I will try to post a pic if I can find it again. It was based on a sharpie design but we can't find the maker.

We also heard about another sharpie design being 48' long that had a 23' coach over the top and full living space under the coach, if you can believe it. Hearing that, the wife made the layout. Yep... serious windage at almost 14' above the water line. We know we would sacrafice a LOT of sailing performance, but as long as it will get us places reasonably, we are happy. 1200sqft of sail made it _possible_ to use sails only. Since it has been done, we hope we can do it.

We are not against using an architect like Par who has made many sharpie designs but thought we would try it on our own first. So far, the theory parts are easy but the actual "how to" is getting to be too much. A set of plans would be great Would anyone want to design such a beastie or does anyone know anything about this existing design?

This had bilge keels for sailing instead of center board like most sharpie designs and drew a little less than 5' of water. It could also be loaded down with a LOT of fuel, water, and food. 200gal fuel/500gal H2O/206cf of food storage in the bilges and other places. It was built HEAVY - on the order of 45% ballast 40k lb dry weight. So far, our stab at designing the same thing comes in about the same weight.

Many have asked why we want to build anyway. The answer is a bit unique for us. We simply can't afford to buy a boat. We CAN afford to move in to the shed, take 2 years to build enough to get it floating, and keep adding to the interior over the years.

Thanks for your patience!

[TollyWally]

For what it's worth you can buy a used one much cheaper than you can build one.

[sabahcat]

Plans for older designs are so cheap

http://www.hartley-boats.com/sailboats.htm

http://www.bruceroberts.com/public/HTML/PLANS4.htm

[PAR]

Yep... serious windage at almost 14' above the water line

You just can't do this in a sharpie hull. This is likely the most sensitive hull form there is to excessively tall structures.

You should get some practical experience aboard 50' yachts. Most novices insist they need and must have a large boat, but after years of experience, they find that 35' yacht is a much more practical craft to own and operate.





This is a 45' Atkins design. The stock plans are $400 which is more then cheap. Of course the scantlings and other spec's are nothing like what you think they should be, but frankly I don't think you are very well equipped to spec out a boat. The interior of this boat could easily be rearranged to suit different needs and most importantly of all it's a founded design.





Next is a 50' yacht from Glen-L and again ridiculously cheap at $700.





This is another Glen-L design a power cruiser of course. These three yachts are across the spectrum of available stock designs in this size. The first is a traditional motorsailor, the next a sailboat with substantial accommodations and the last a powerboat.

There are plenty of designs available. Your insistence on a sharpie in this size seems at the very least inexperienced.