Type of Wood for Hull

[stevey_frac]

Thanks for your thoughts.

I would classify myself as a 'dreamer' without the requisite 'craft skills' to properly build a boat, which is exactly why I selected a strip planked hull design in the first place. While I can rely on my father to help me build the cabin a bit, it would be awesome to be able to say I built the hull at least by myself.

I'm in the great lakes area, close to Toronto. What local woods would you recommend?

I do plan on doing a lot of reading! I've purchased some books already, and I'll have studied many more before I start making any 'chips' as S. Weaver stated.

EDIT: Two questions... doing a bit more reading, I find that white oak is a pretty decent boat wood, and its local to these parts. Why can't I use white oak?

Second: Why can't I wrap this thing in fiberglass? Seems like it would improve things in pretty much every way?

--Steve

[preaton]

Steve,

Don't let the purists put you off. I have built a strip planked hull (Golden Bay) on Selway Fisher's web page. Strip planking is an excellent way of building a beautiful looking durable round bilged hull without needing to take too much time out from your day job to get the requisite skills. It is one of the best ways for the amateur to turn a dream into reality.

That said, it is mucky, uses lots of epoxy and requires hours and hours of sanding to get a fair hull. The strip planks act as the core of the hull which is usually fibreglassed inside and out. It makes a strong, light hull. A 30 foot Edwardian would be a difficult one man project, simply from handling the long strips. You will have plenty of time to hone your woodworking skills with the cabin and interior joinery.

The advantage of western red cedar is it is very resistance to rot (should your fibreglass be perforated), it is very light and easy to work. It should be fairly easy to obtain and in the end will be only a very small part of the investment you will be making in your boat.

What machinery are you planning for the hull?

Cheers

Paul

[stevey_frac]

For machinery, I've been looking for a compound, and I plan on making my own wood-fired monotube.

I started doing the calculations for the boiler design last night, but my thermodynamics are a little rusty. I'll have to think about it a bit more before I start cutting.

--Steve

[Bob Cleek]

Well, this thread may be a little stale, but I can't resist... Your fiberglass (or expoy/Dynel) sheathing will be "perforated" as soon as you drill your first hole to screw on a fitting. In reply to your thought that "fiberglass sheathing" seems like a great all-around solution, just google "balsa core + fiberglass + rot," click on "images," and see what you bring up. Plastic sheathing of wooden boats is a viable alternative if the boat is dry-stored indoors, and sometimes the best option if a small boat is going to be regularly trailered. Beyond that, it has serious limitations. Practically speaking, there is no way to "encapsulate" wood so that moisture cannot find its way into the wood. People who sell resins, fabric, and plywood, etc. will say so, but it isn't so at all. It's also, as even its proponents who are honest will readily admit, a very labor intensive, nasty way to build a boat. (Huge amounts of toxic fumes, nasty sticky stuff you can't clean off of yourself without bathing in noxious solvents, interminable sanding and more noxious dust, and so on.) Your mileage may differ, but for my money, and time and labor, it's a lot easier to build a planked hull traditionally than a sheathed stripper. It's also a lot easier to repair a traditionally planked hull, if that time comes, and it will. And, frankly, I don't believe it is any more difficult for a first timer to build traditionally than with sheathing over strip planking. Strip planking has its own learning curve, which may be a bit less than learning how to spile and hang plank (which isn't hard if you follow the directions in the books,) but what it lacks in skill demanded, it makes up for in the builder's need to master the technology of polymer chemistry! If you are scared off by what somebody has told you about the skill required to hang traditional carvel plank (yes, it used to be an arcane art... craftsmen didn't give away their secrets because that's all they had to sell) just visit the WoodenBoat Forum (http://forum.woodenboat.com/) and read the lamentations of guys whose 25' boat bottom is covered with expensive Dynel and epoxy resin... which refuses to cure because the temperature was wrong or the moon was in the wrong phase when they mixed it or whatever. You'll may well spend a lot less money on materials building traditionally than with strip and sheathing. Epoxy is very expensive stuff.

So... I'm "just sayin'" It's worth thinking a lot about it before you make the leap. At the end of the day, you aren't really going to save anything building with strip and sheathing. It's a lot of work to build a boat any way it's done, but ask anybody who's done it both ways and I'm betting they'll tell you they'd rather hang carvel plank any day of the week.

[malcolmd]

Get a copy of Selway Fisher's book on strip plank building it's good.

- I think the design expects to be clad inside and out with Epoxy and Cloth (fibreglass or kevlar etc.) and according to Gougeon Brothers book (the people who invested West Systems Epoxy and composite construction) - ((this is freely downloadable here)) this will render the wood impervious to rot and water... On this basis Paul Fisher (Selway Fisher) comments that he has seen hulls built with almost ANYTHING, including low grade deal as a core.

My only other thought is that from my reading English Oak (which may be a whole other animal) contains oils that will play havok with glue and epoxy adhesion - so you might want to stick with the WRC or some other timber..

My final, final thought is that most people reckon (and my own estimates for the boat I am building agree) that you will have spent about £10,000 ($15,000) minimum by the time you have finished - so attempting to save money might be (to abuse the saying) "spoiling the ship for a few bucks of timber"!!

Mal

[marinesteam]

It looks like many woods can be used to build a successful strip built hull. As it's been noted the epoxy and sheathing encapsulates the wood making the rot resistance less of an issue. That said, you would still like the core to be more rot resistant than less as water can still get to the wood in case of skin failure or damage and since the core is now encapsulated it's less likely to dry out. I'm currently researching building methods as well and from what I've found there should be locally available woods that are acceptable other than oak. Oak would be low on my list due to it's tendency to rot and it's heavy weight. Douglas fir and tulip poplar are often cited as good, economical strip woods. I think it's important to note that a LOT of effort will put put into building the hull, and epoxy will be the big expense, saving a bit with a poor wood species or quality selection is false economy.

Ken

[Lopez Mike]

Something I've been unable to determine is what the weight differences are between strip or plywood with glass sheathing in and out v.s. traditional carvel planked construction.

Most of the traditional hulls I've seen are really heavy. I have a plywood 24' hull right now and it is relatively light. This makes for a number of good things such as a lighter trailer and tow rig as well as better performance.

The Devlin boats (plywood and epoxy) are well built and have no incidents of rot.

My current hull has several strikes against it. It is severely esthetically challenged. Straight sheer and really horrible workmanship. And the materials were rejects from some sort of failed goat shed project. Sad. Why bother.

I have seen a lot of plywood boats built over frames and stringers with no epoxy or glass beyond what was needed for bonding. No sheathing. Some of them were really old and the ones that had been cared for were sound.

Thoughts?

[DetroiTug]

What rots wood is trapped moisture. I agree with Bob above, but only when epoxy encapsulation is poorly done and it is not properly cared for. There are many examples of older boats of wood core and either fiberglass or epoxyglas construction that are holding up just fine.

Sure Carvel is a great traditional means of boat building. I don't agree that Carvel construction is not all that difficult, the rabbeting of the stem alone is far out of the scope of the novice woodworker. The fitting of compound angles takes years of experience and know-how. The reason some still favor carvel is they are typically built from the proper woods and generally better cared for. Any hull construction type can enjoy longevity if properly cared for. All of these different hull types require different levels of maintenance requirements. From low to high, I would put fiberglass construction at the lowest levels and Aluminum and steel just below that and painted plywood at the highest level. Then the gamut of various cored and encapsulating hulls somewhere in between

Back in the 60's, wood boats were plentiful and fiberglass was in it's infancy in new boat construction and fiberglass as a repair medium was first being experimented with. Simple construction of plywood over frames - then sealed and painted, held up just fine for many years. The problems were that people had no idea how to care for them or just didn't. Even when many did take care of them, they overdid it. Pulling the hull from the water wet and then tightly tarping it up and not allowing it to dry out, some of these hulls lasted only a few seasons. Whats worse was most of these tarps were actual tarpaulin which was muslin and every time it rained, it leaked and re-moistened everything. Which gave wood boats and especially plywood boats a very bad reputation. I own a 1964 ChrisCraft Speedboat of Bruynzeel plywood construction. The hull was fiberglassed to the bootstripe at the factory 51 years ago. It still has the original bottom in it with the same fiberglass covering. From the interior/bilge side it looks just fine. This boat has been properly cared for. Ironically, the only wood that has been replaced was the section of the sides directly under the foredeck. A thin strip where water wicked in from the deck surface and was always in the shade and never dried out in the sun like the rest of the hull. The guy that owned it before me (pre 1991) would let it dry out every fall and then pull it outside and spray the entire bilge with mineral spirits.

According to some of the YouTube boat repair experts and there are several, since about 1990, boat manufacturers no longer seal or glass-in the floor timbers between the hull bottom and floor. They are simply glassed in where they contact the hull and no other sealing is done to them. Then the floor is laid down unsealed and glassed over the top only to the gunwales or sides. If any moisture gets in this cavity, it wreaks havoc in a very short time. There are several boats around that look like new and the whole floor and linear timbers are completely rotted out. And it is a major undertaking to repair this damage. It's obvious why the manufacturers do this if one has ever priced the resins, it saves a lot of money.

I think the most important consideration with core wood is it's expansion rate by temperature. There are charts that show which have the least amount of expansion. This is important because as the wood expands, it's going to crack (if too weak) the much more brittle encapsulation and render the whole sealing process futile. The other issue that causes early failure is there is simply not enough encapsulation used. By the time a layer of West system is laid and faired, there really isn't much left in the way of it's structural integrity. It's pricy and in the drive to save money, the whole project is sometimes sacrificed. If done properly and cared for, it works just fine.

-Ron

[S. Weaver]

Mike -

I can lift my stern up off the rear jack stands by myself without the machinery in it, and my hull is fairly robust. I'm guessing the overall hull is @ 700 lbs for 24' LOA 6' W 1.25' D. Most folks know, but a picture is here:
http://www.thesteamboatingforum.net/for ... ?f=4&t=566

I got a pass from Bob because I'm trailering it ...