Pure wood, no leaks?

[Kaa]

Is it viable to build a small boat with the following specs?


Built out of pieces of wood. No plywood. No laminations.
No impermeable wood coatings -- no epoxy, no glass, no varnish.
Can alternate between living on the hard and being on the water without leaking. Say, spend a year in a barn, then be launched and be dust-dry inside without a take-up period.The basic issue is whether there is a design (or a construction technique) that will allow for the wood to move without compromising the integrity of the hull.

Kaa

[Mrleft8]

In theory, yes. Consider the Birch bark canoe.

[Kaa]

In theory, yes. Consider the Birch bark canoe.

Well, yes, a dugout canoe qualifies as well :-) And rafts. But I was thinking of something closer to conventional boats or dinghies.

Kaa

[P.I. Stazzer-Newt]

You'll have looked at a riven Malmo oak stave then?

[Andrew Craig-Bennett]

This is strictly theoretical and I am not actually suggesting it...

Going on from Triturus' riven oak staves - the Viking construction where the stakes are rivetted to each other along the laps, but lashed to the frames, might achieve it. The stakes will move together and the lashings might accomodate the movement between frames and shell planking. I fancy I would want to cut the planks out in pairs, for this.

[Don Z.]

Well, I think you could build it tight enough that it wouldn't need to take up... but then the wood would soak up water, and expand, and well, there goes the frames!

It may be a technique, but I don't think it's the preferred method.

[erster]

edited:

post not applicable because of the no paint build...

[outofthenorm]

You may have gone too far when you specified "no varnish" - assuming that means just raw wood with no coatings at all. It's the coatings that minimize or equalize transfer of moisture, so bare wood will move around more than coated wood. But if you allow paint in your system and some shellac, I'd think that a carefully constructed double-planked riveted or screwed hull (a la Herreshoff), with shellac between the layers and the whole well painted, would serve.

- Norm

[boylesboats]

Is it viable to build a small boat with the following specs?


Built out of pieces of wood. No plywood. No laminations.
No impermeable wood coatings -- no epoxy, no glass, no varnish.
Can alternate between living on the hard and being on the water without leaking. Say, spend a year in a barn, then be launched and be dust-dry inside without a take-up period.The basic issue is whether there is a design (or a construction technique) that will allow for the wood to move without compromising the integrity of the hull.

Kaa

Ain't ya gonna paint it?

[Andrew Craig-Bennett]

I think that first growth teak, built carvel, could achieve this - Mirelle is so built and whilst she is indeed painted she hardly leaks after an 18 month spell ashore.

I don't know if this comes within the "no laminations" ruling but the old P&O lifeboat method - double diagonal teak - achieves the result quite easily.

Besides lifeboats on P&O steamers (which had to stand passing through the Red Sea in 40deg C and then the North Atlantic a few days later and not leak when launched, RNLI lifeboats and many RN ships boats were built this way.

[Daniel Noyes]

the answer is yes, most of the traditional methods when built with care and maintained meticulously will pass your test.
The big test comes with hard use and here the Dory built method was found to be superior. The dory is famous for the amount of abuse and neglect it could take and still stay tight on launch.

[SaltyD from BC]

Spline planking

[StevenBauer]

I've done it. :D Harry Bryan's Thistle (his Fiddlehead with pedal powered fin drive) Sometimes there are a few drops of water in her but I think they drip down from the paddle I use for reverse. She's got some varnish but, like paint, it isn't impermeable so I think it counts. ;)


http://im1.shutterfly.com/procserv/47b7cc24b3127cceb2432cafd8d300000036100AbNnLhizaOW KA


http://im1.shutterfly.com/procserv/47b7cc24b3127cceb243597198af00000036100AbNnLhizaOW KA

http://im1.shutterfly.com/procserv/47b7cc24b3127cceb2435de8190400000036100AbNnLhizaOW KA

http://im1.shutterfly.com/procserv/47b7cc24b3127cceb243f333198800000036100AbNnLhizaOW KA


Steven

[RonW]

I think it was invented about 120 years ago.
It is called traditional strip planking...
and a couple of links to show how it is done...

http://www.pulsiferhampton.com/

http://www.westpointskiff.com/J_Construction_%20page3.htm

[Kaa]

Hmm... interesting responses.

First, a bit of clarification -- yes, no paint. I have in mind something similar to what Michael Beckman is talking about in his Traditional Finishes thread -- bare wood, probably oiled, but that's it.

I am also not looking for methods to fix a leaking boat (e.g. spline planking). I understand that with proper maintenance of the seams most any properly constructed boat will survive wet <-> dry transitions, at least for a while, but that wasn't the question. The question was about building a boat that needs no seams maintenance at all.

It's been a surprise to hear from ACB that a carvel boat does well after a dry spell on the hard. Perhaps old-growth teak moves very little -- but in any case, there's not much of it left and what's available is likely to cost a completely unreasonable amount of money.

Strip planking -- hmm... I'm not sure. Note again -- a small boat, no epoxy, no coatings. If you're just nailing strip planks together, the hull will have to be quite thick.

Double diagonal -- is that double carvel? Same problems as with the Mirelle example, is it viable without old-growth teak? And is there supposed to be something in between the two hull layers?

Traditional flexible Nordic boats -- that, I guess, is what I had in the back of my mind. They are designed to move and the frames do not lock them into a rigid structure, so presumably they would be able to handle the dimensional shifts well (especially with the use of riven planks and such). But I am curious what happens in practice. There are enough traditionally build (nailed, no epoxy) faerings and similar boats -- do they leak for a while after a spell on the hard?

Kaa

[Paul Pless]

http://www.soomaa.com/pildid/galerii/pilt_65.jpg

[Daniel Noyes]

the answer is yes, most of the traditional methods when built with care and maintained meticulously will pass your test.
The big test comes with hard use and here the Dory built method was found to be superior. The dory is famous for the amount of abuse and neglect it could take and still stay tight on launch.

Its quicker than saying it again in different words...

Think well maintained boats, high speed river transport, eg wherry's, white halls, gigs, the very best of the best, kept under cover in boat houses close to the river with relatively constant temperature and humidity.

Why are you asking? because really staying dry on launch was not very important to most of the old time working craft, it was how much could they haul, how fast could they sail and row, how $, and how long did they hold up under the abuse before going to pices...so staying bone dry on launch was not really one of the characteristics designed for.
Dan
http://dansdories.googlepages.com

[Kaa]

Why are you asking? because really staying dry on launch was not very important to most of the old time working craft, it was how much could they haul, how fast could they sail and row, how $, and how long did they hold up under the abuse before going to pices...so staying bone dry on launch was not really one of the characteristics designed for.

Yep, that's why I didn't ask about old-time working craft. I asked for a technique that will produce a small wooden boat with no coatings, one that would tolerate frequent changes between being on the hard and being on the water with no leaks. I understand it's a different spec from the historical small wooden boats.

Kaa

[RonW]

Well I think you failed to define what you think is a small boat.
In the west point skiff link I gave above, he builds a 16 x 6 skiff.
To me, that is a small boat.
If you are thinking something smaller, like a 13 x 4, such as a peapod for example, then look at lapstrke.

[Frank E. Price]

A coracle, with tarred canvas replacing the walrus hides. Probably not what you have in mind, but would work. Plenty of skid strakes over the bottom. Could be framed with wood off the beach, but the canvas and tar would have to be imported. Size and shape are much more flexible than most might have in mind regarding the type.

A dinghy built like a canvas covered canoe would also work, though it probably would not get along without paint.

Getting seams accurate enough to survive a year in a barn before launching and then not leaking a drop from an amateur builder is a very tall order. Especially if the cycle is to be repeated for several years and still not leak on launching. What have you got against a little bilge water? Don't forget the raw linseed oil. Hiscock indicates it can be done, but his dinghy probably wasn't built by an amateur. How disappointed will you be if it does leak a bit on launch? Or if it leaks quite a bit for a week or two?

Frank

[Keith Wilson]

I asked for a technique that will produce a small wooden boat with no coatings, one that would tolerate frequent changes between being on the hard and being on the water with no leaks.No leaks? No can do, short of a dugout, and even those check. Wood moves, and because trees are only so big and a wooden boat has to be made out of lots of little bits, joints move too. Some species move much less (like Andrew's example with teak), but for NO leaks, something else besides wood is required. Canvas (like a wood-canvas canoe), tarred something (like a coracle), or double-diagonal planking with something waterproof between (canvas in white lead?). Traditional lapstrake does pretty well because the joints allow some movement, but a small leak isn't no leak. Wood's great stuff, but you're asking it to do something it can't.

If you have to have absolutely zero leakage, build it cold-molded, or strip-planked with sheathing, or use plywood (and a cold-molded boat is just a large funny-shaped piece of do-it-yourself plywood).

[StevenBauer]

I really don't understand the whole 'need' for 'no leak' boats. People justify using plywood to fill this 'need' but I just don't see what the big deal is. So your boat leaks a little. You stay dry up on the floorboards. So what if there is a little water down there below them. Even if the boat doesn't leak a drop you still end up with some water down there.

Steven

[P.I. Stazzer-Newt]

I really don't understand the whole 'need' for 'no leak' boats. ...

Its the difference between a maths problem and an engineering problem:
Take for instance the infinite L-Pad resistor problem - this classic calls for an infinite supply of identical resistors and a good supply of Zero resistance cable.

Any engineer with the wit god gave a housebrick looks at the spec and says "One, One and a half, -no - about 1.6 - that'll do." takes about thirty seconds.

The Mathematician on the other hand - notes the similarity with the recurrence in a fibonacci sequence and produces the exact answer - pointing out that it is irrational and contains an term of root five.

It will take him anything from a month to twenty years - and provide boundless joy... and is totally without practical application.

[dmede]

Yep, that's why I didn't ask about old-time working craft. I asked for a technique that will produce a small wooden boat with no coatings, one that would tolerate frequent changes between being on the hard and being on the water with no leaks. I understand it's a different spec from the historical small wooden boats.

Kaa

I think what's at the root of this issue is that even if it is possible to get a boat that meets your build specs and does not leak upon launch after a full season or longer out of the water, what's the point? What do you gain if the work required to achieve that is X number of times more difficult and costly than current techniques that take advantage of the fact that wood will swell when wet and close any leaks in short order?

Taking up may seem like a defect or deficiency in design but I think it's really an elegant solution the very problem your asking about.

[Kaa]

Interesting how the opinions here range from "no big deal" to "flat out impossible" :-)

More clarifications. I am not thinking of a boat that would spend half a year in the water and be hauled out for the winter. I'm thinking of a boat that would live on the hard and would be chucked into water, say, every week or a couple of weeks for anything from an hour to a few days. That's a lot of dry-wet-dry cycles.

And, by the way, on a conceptual level I don't think boats should leak. Period. Yes, it's not necessarily fatal, and yes, you can live with it, but to my mind water in the bilge indicates a problem that should be fixed. Maybe I wouldn't make a good engineer... :D

Re skin-on-frame boats -- yes, they are also the type (along with dugouts, rafts, and such) which would stay dust-dry. Thanks for reminding me of them. But again, I'm wondering about wooden boat building techniques -- I know how proper kayaks are built :-)

And also again, I know how to make a leakless boat. My current one, being ply-epoxy, is quite dry. I am interested in whether it's possible to make one under limitations listed in the first post.

Oh, and what do I mean by a "small" boat? Hmm... let's say beachable. If a couple of men could drag it up and down the beach, it would qualify as "small".

Kaa

[RonW]

Kaa- I don't believe you got the disscusion you are looking for.
I say you can use any traditional method, strip-lapstrake-board on batten-double planked- or even carvel. But the problem is the dimension of the lumber and the lumber being properly dried or acclamated. You need a moisture meter and lumber that has been fully dried and shrunk to it's smaller dimension. About 10% moisture.
You can't use air dried lumber or construction grade lumber that has a moisture content of around 16% and not expect it to continue to dry and shrink as you build the boat or leave it sit on the trailer. Then you end up with gap city, and thickened expoxy seems to be a favorite forum fix. There are plenty of people and professional botbuilders building small traditional trailer boats that do not require sitting in the water for days and being bailed till they swell up and quit leaking like a sieve. Go for it........

[Charles Burgess]

The traditional Ashcroft method works very well. Planking is two alternate diagonal layers with linen cloth that is soaked with boiled linseed oil (BLO) in between the plank layers...that is the traditional laminate that will bond the plank layers together rather than the expoxy/fibercloth used today. Then coat the hull inside and out with BLO; steam bend the oak frames in and then coat them as well. You can substitute Tung oil for the exterior coatings if you desire.

The heavy use of BLO will help prevent water absorption to a large degree, and helps keep the wood stable as well. Get a auto-drip coffee maker, pour the oil where you normally put water in and turn it on (do this out of doors) and the coffee maker will heat up the oil into the coffee pot to help it penetrate the wood deeper and faster. Having the heated oil in the coffee pot, which has a nice handle, just makes the job so much easier and less messy.

[Bruce Taylor]

Get a auto-drip coffee maker, pour the oil where you normally put water in and turn it on (do this out of doors) and the coffee maker will heat up the oil to help it penetrate the wood deeper and faster.

That's a handy tip. Thanks, Mr. Burgess.

[Charles Burgess]

That's a handy tip. Thanks, Mr. Burgess.

One day I poured myself a cup of fresh coffee from my auto-drip coffee maker and sat down in my mouning chair to figure out how to make applying BLO to a hull easier and less messy...I looked at the mug of coffee...I looked at the coffee maker on the bench...a lot of answers come while on the mouning chair - don't build without one.

[Keith Wilson]

And, by the way, on a conceptual level I don't think boats should leak. Period. Yes, it's not necessarily fatal, and yes, you can live with it, but to my mind water in the bilge indicates a problem that should be fixed. Maybe I wouldn't make a good engineer... I am an engineer, and I say as long as it doesn't leak faster than you can comfortably bail it out, what's the problem? :D

Y'know, maybe your best bet would be traditional edge-nailed strip planking with good tight-grain cedar planking and lots of little steamed white oak frames (unless you want to take out a second mortgage and buy teak). That was the standard way of building lake fishing boats all over the Midwest until the ubiquitous tin skiff came along, and the way they were used was pretty similar to what you're describing. You'd have to be very careful fitting the planks, and maybe you could use the old trick of compressing a groove in the plank edge with a roller and then planing it flush; the squashed zone will seal tightly as it expands. Is paint OK, or does it have to be oil? If you tried to keep the wet-dry cycles as gentle as possible (don't let it sit upside down in the hot sun, don't let water sit in it) that might be OK. Weston Farmer has a good discussion of this method in his book, or maybe it's in the article with the Dolly Varden plans.

[ChrisF]

Francis Herreshoff built a kayak by sawing out hollow lifts, gluing them together, and carving out a boat with the grain running all the same direction. Sort of a glorified dugout. Wouldn't be a particularly light construction, and you'd need goop, but it wouldn't have to be epoxy.

But I don't think anything made of wood can get by very long outdoors without coating. Even teak goes away gradually if exposed. And oil finish on a boat, in my experience, is a snare and a delusion.

Anyway, I'm with Keith: you won't dissolve, I bet. If you're having any fun at all in a small boat there's a little water getting in through that big hole in the top, anyway.

[TommyD]

While it might be possible to build a boat such as you propose, I would not want to go to all the trouble to construct a tight vessel that has a shortened life span. I have been earning my living in wood working for over twenty five years and regardless of the application I have learned the single most important bit of information about wood. It never stops moving! Even wood work in dry homes tend to move, blowing joints and compromising the strength and asthetics of the project.

I recently completed a 17' solid Mahogany Barrelback runabout. We used conventional construction techniqes with state of the art epoxy adhesives and coatings. Plank on batten construction glued and screwed is exceptionaly strong and durable. The entire hull is a solid entity. While we do not have a huge gas motor on board, there are 840lbs of batteries and several hundred pounds of Electric motors and shafts. The interior is sealed with epoxy clear coat and the exterior is many coats of varnish. This hull will still be in excellent condition many years from now.

So my personal choice would be to build a solid hull and seal it with at least two coats of finish not only for protection and stability, but the finish also brings out the beauty of the wood which is why most of us love wood boats so much in the first place.

Tommy