Building without forms

[Larry Westlake]

Greetings, all.
New member here, first post.
Long-time lurker, though, so I feel like I know the place.
I have seen occasional interest in these forums about "open mold" wood-canvas canoe construction, and I have built two canoes that way (as well as several rowboats - it's basically the same system).

Something that’s even more fun is building with no plans, molds or jigs whatsoever – you work right out of your head, shaping the wood to match your own ideas. I call it the "free molding" or "mind bending" system. It’s the ultimate in both freedom and responsibility for a designer-builder. I can find no real discussion of this here, with only one detailed mention by Greg Nolan of no-form methods for skin-frame craft. The boats I’m building, however, are standard wood-shelled canvas-wrapped canoes, not drum-skinners. I’m now working on my second mind-bent canoe, and am about to start planking it.

Here's a picture of the first one at the wrapper stage. It's curing in the rafters now.

I didn't invent the system. It's old hat for bush builders, similar in concept to bark construction, but very different in procedures.

Is anybody interested in a description of the process?

 

[Dan Miller]

I suspect there are a number of people interested in learning more about your techniques. Feel free to elaborate. You might also consider submitting an article on your methods to our journal, Wooden Canoe.

Looking forward to more,
Dan

 

[beaver]

Greetings, all.
New member here, first post.
Long-time lurker, though, so I feel like I know the place.
I have seen occasional interest in these forums about "open mold" wood-canvas canoe construction, and I have built two canoes that way (as well as several rowboats - it's basically the same system).

Something that’s even more fun is building with no plans, molds or jigs whatsoever – you work right out of your head, shaping the wood to match your own ideas. I call it the "free molding" or "mind bending" system. It’s the ultimate in both freedom and responsibility for a designer-builder. I can find no real discussion of this here, with only one detailed mention by Greg Nolan of no-form methods for skin-frame craft. The boats I’m building, however, are standard wood-shelled canvas-wrapped canoes, not drum-skinners. I’m now working on my second mind-bent canoe, and am about to start planking it.

Here's a picture of the first one at the wrapper stage. It's curing in the rafters now.
View attachment 19155
I didn't invent the system. It's old hat for bush builders, similar in concept to bark construction, but very different in procedures.

Is anybody interested in a description of the process?

"The Indians in the far north have been building canvas covered canoes without using a form for many a moon. Its all done by eye using simple tools and materials at hand. For some details on the construction see........AITNANU by Serge Jauvin, 1993 and CANOE CONSTRUCTION IN A CREE CULTURAL TRADITION by Garth Taylor, 1980."

 

[Greg Nolan]

I, for one, would be very interested in seeing your technique -- either here, or as Dan suggested, in an article in Wooden Canoe.

 

[Craig Johnson]

Count me in on the interested to see more!

 

[pklonowski]

Given enough detail & pictures, I can imagine a series of articles in the Journal... Do it, please!

 

[Larry Westlake]

How I do it


OK, thanks all. I'll go ahead with a brief.
Thanks particularly to "Beaver" (a voice crying in the wilderness), whose advocacy in these forums for the oft-forgot genius of back-woods builders has been a great pleasure to me in my lurking.

Here’s how I did the first two, but the method is quite flexible, and does not have just one 'best' solution.
No drawings are needed. Gunwales, stems, and ribs were pre-bent by eye to shapes I just knew would work. Smaller ribs were bent inside larger ones so the shapes coordinated. The assembly of gunwales and thwarts was the only building base. Stems were mounted to that and braced to each other with a keelson strip. The keelson was strutted to the thwarts to fix the hull depth. Then the pre-bent ribs were mounted in their places, and stringers lashed inside to align them. Ribs that didn’t line up perfectly were dipped in boiling water and tweaked till they did. Most clamping was by lashing – its cheap and plentiful, doesn’t mark soft cedar, and doesn’t add weight that can distort the light structure.
I started planking at the centreline as usual. Ribbands and lashings that were in the way were removed, the area longboarded, and the plank fitted, set, and tacked. Clenching was completed immediately, before doing the next plank. By the time you are done planking, all the temporary stringers and struts are out.
Everything else is the same as usual.

Almost everything is very easy as long as you don’t make any mistakes (and some of them are easy too!). The only part that really is tough is fitting and fairing the endmost ribs. The middle half of the boat lines up without hassle, but the end quarters require a lot of artistry and painstaking attention to manage the transitions of form smoothly. The ribbands are your guides and must be followed. If you try to fudge things there is hell to pay later. On the plus side, you can fart away at it for as long as you want (and probably much longer) until you are sure it’s right, with the ribs all kissing the ribbands relaxed and unforced. It doesn’t do a sudden-death time-out like some critical operations on boats – not like steaming on a carvel garboard, f’rinstance. The shorter and fuller-ended the canoe is, the harder this area will be to fair. The current canoe is a chubby 10-footer so the job was very difficult and took most of a day, with several ribs botched and re-done. On the previous canoe, a rather fine-ended 12-footer, this job was fairly easy.

Once that job is done properly, the remainder is a piece of cake, and does not require any different knowledge or skills than the factory method.
　
Because I am new at this method, and don't live near any surviving experts (if there still are any) that I could learn from, I did break my own "no artificial aids" rule on these first two canoes. To bend the ribs I used a crude box frame of scrap wood that was marked on both sides. This is shown below with the ribs all in place (note the flat-strap cloth ties that don't mark the hot cedar). Those marks and a centre-mark were transferred to the ribs before removing them from the jig to make it easier to achieve symmetry during frame-up.


I can't make image formatting work the way I want in the forum's WYSIWYG editor, so I am going to have to make a web-page with photos of the building process for the two full-sized boats. I'll send a link in a day or so.

In the meantime, have a look at the existing web page for one of the several models I built to self-teach before risking large amounts of valuable material.
Link: http://users.eastlink.ca/~westlake/Rat Canoe Model Web page.htm

Larry

 

[greenvilleguy]

Wow! Very impressive.

I'm wondering if I couldn't make some rib molds from plywood based on known plans, bend the ribs to specs and then construct without a full mold as you describe using the dimension from the plans.

 

[Rob Stevens]

Very interesting! Are your thwarts morticed, lashed or bolted?

 

[Larry Westlake]

Wow! Very impressive.

I'm wondering if I couldn't make some rib molds from plywood based on known plans, bend the ribs to specs and then construct without a full mold as you describe using the dimension from the plans.

I'm sure it could be made to work, after a fashion. It negates two things I like about the method; simplicity and directness. But it would not quite achieve two major benefits of molded methods; control and predictability. You'd probably only be able to bend a couple of pairs of ribs (4 ribs) on each plywood form, if you wanted to stay reasonably faithful to the design, so for a fairly normal number of ribs (40 to 50) you'd need ten or twelve forms. It would not be possible to stay 100% faithful to the chosen design in any case, since ribs bent on such forms would be without bevel. When they were canted into place to produce the effect of bevel, they would no longer represent the designed sections. You'd have a similar boat, and that might be OK, but you wouldn't have the same boat as the design. If anybody lost me there, it's the same as what happens when you slice a carrot on the diagonal - you don't get the circular theoretical carrot cross-section, you get an ellipse.
Instead of plywood forms, consider drawing the rib shapes onto a ply backboard for the ribjig cheatbox, spaced away from each other about the thickness of the rib pairs so you can still see them after initial ribs are in place.
It would not eliminate the need to painstakingly fair the ribs, since a lot of the tweaking is to correct for the fact that the nominally required cant does not produce the ideal bevel automatically at every point along the length of the rib, so they need to be checked & strongarmed into full compliance.

 

[Larry Westlake]

Very interesting! Are your thwarts morticed, lashed or bolted?

On these two boats, butted and screwed. For such small canoes, that is adequate for a long time, but when it fails it is very difficult and annoying to get at & fix. These two canoes are research & development canoes, and the next one will be too. I'm taking as many shortcuts as possible on my way to the target issues, which are the issues I want answers to. The canoes will be saleable, but the price will reflect the rough-and-ready approach. Once I get really good at the method, and can be certain I won't have an otherwise perfectly good canoe spoiled by a major error, I will take more care for the things that have nothing to do with the current research goals.
As you will see when I post the construction pix (not tonight, maybe tomorrow) and compare them to the model report, I have never done everything the same way twice. I don't want to know only one way that works, I want to know what DOESN't work, as well as having a clear understanding of different benefits to different approaches.
Rob Morris's book on skincraft has almost all the information a person would need to build a boat this way with all joints lashed. He doesn't cover the issue of lashed edge-contacting planking, since (if I remember correctly) his boats are all what I call drum-skinners, but the problem has been dealt with. Not only are there many lashed-planked boats in other parts of the world, but the very earliest fur-trade canoes built for trading in BC and along the Columbia River were all-cedar all-lashed plank-built because the birchbark here was unexpectedly too crappy to make freight canoes out of after they'd hiked over the mountains. Actually, I got some of my ideas, information and appetite to try this method by reading David Thompson's journal accounts of how he built those boats, under severe duress, way back in 1811.

 

[greenvilleguy]

Thanks Larry. I forgot how much the ribs are actually canted.

 

[Larry Westlake]

OK, got the editor figured out. Process pics follow.

First pic is an important detail for accommodating the second canoe’s combo of shorter length & absence of tumblehome. On the first canoe I allowed tumblehome, which much simplifies the rib-bending. I didn’t want TH on the second one, so I had to estimate frametop widths to ensure that my topsides ended plumb or nearly so. With the gunwales assembled, and the number of ribs known, I marked positions and determined what the top widths of the various frames should be, from the gunwales. Then, as I was bending the ribs into the cheat frame, I inserted spacers (visible) to obtain the desired top width for each frame pair. (That’s my best shop helper ever, showing off the ribs. We bent this bundle together on her March break from university.)



Second pic is the no-mold method of bending glu-lammed stems. The plastic wrap keeps the glue contained but also applies some glueline constriction as the lam-bundle is bent, tho the surgtube wrap supplies most of the required clamping force. The wrap all comes off when I run the thing through a tablesaw. The chunk of straight scrap clamped at the heel ensures a straight section for mating to hull midline.


Third pic shows the wrap method of hygenical glulam-bending applied to a normal form jig (this is not for one of the mind-bent boats, but for an ‘open form’ canoe). Note there are two separate sections in each bundle, one will be used as a wooden outer stem. The wrapper used here is superior to the building poly used in the other pic – it has tensile quality better suited to the job. Cut +2" wide, wrapped as spiral. Available free in huge quantities from lumberyards, used for wrapping lumber during shipping.


Pic 4 is the first free-molded full-size canoe. The square chunk of scrap is just a brace to keep the heights correct, everything square, and the keelson centred till the ribs are in place. The way I lashed the struts at first was not satisfactory, the lashings got in the way of the garboards. Its better to lash thru holes in each end of the strut, so that the strut stays in place even when the keelson lashings are released to allow the gdb to be installed first. Stem/keelson connection also proved inconvenient. Note butt/screw thwart ends and simple deck fastened thru gun’ls. Note also that the gunwales on both these boats are laminated to curve. Done double-wide, wrapped & clamped to bench, ends wedged up to whatever desired curve, sawn into two when cured. No hogging problems will occur with these boats.


Pic 5 is the second canoe. Have not yet replaced first-try struts with the improved holed ones. Better deck design. Better stem heel design. Note that these two boats, like the two open-mold canoes I built use keelson only because their intended use is for double-paddling. Keelson is best way to attach removable floorboards, seat, & foot stretcher. For standard W/C construction w/o keelson, just use a temporary one, a ribband even. Notched keelson is glued up, no slower, easier, more accurate, and less wasteful than any hand method of notching a one-piece keelson.


Pic 6: Better deck/breasthook design on second canoe – probably not something that would be a good option for the classic mold method, but it works here. Eliminates need for tapered shim out to tips of canoe, allows use of shorter gunwales, is easier to locate & assemble single-handed. Gives far better bite & bury for stem top screw. Since bookmatched, uses only a tiny chunk of wood.


I'm at my attachment limit, so that's all for tonight.

Enjoy.

 

[Larry Westlake]

Continue thread: Building Without Forms

Continuing on about building without forms...

Pic 7: First canoe, first ribs going in. No, they don’t look exactly right, but they soon will.


Pic 8: First canoe. More ribs, still looking wonky. The middle ones are fixed in position, so the brace has come out. Fear not.


Pic 9: First canoe. Ribs faired to lashed ribbands. Note that ribband tips need to be stepped to fair to outside of stem and inside of ribs. Stem & keelson not yet bevelled. Endmost ribs not yet notched & fitted.


Pic 10: broadstrakes and gore planks on. The shape is now locked, and there are no more aids in place. Wish I had done the garboard first - thought I needed to keep the top post lashings, but it turned out that there was a better way. Complicated clenching - I needed a helper. Note notching in progress for halved ribs.


Pic 11: All planked up, still moist from cupping them into place. Note that stemface is very wide beacuse I will be using deep hardwood cutwaters instead of metal bashbands.


Pic 12: You cannot be a boat designer without thinking A LOT about buttocks.


Everything from here is "by the book".

Larry

 

[Greg Nolan]

Impressive. Thanks.

 

[Larry Westlake]

Second no-mold canoe

Here is the second no-mold canoe. I just finished planking it this evening.
I intend to make this canoe my first foray into filling the canvas with latex based compound.

Larry Westlake

 

[Danroy]

Wow I'm really impressed by your way of doing things and the canoe you have curing is really beautiful. Haven't been to Sechelt in a long time but if I'm ever going through I would love to see your work up close. Thanks for sharing your story.

 

[Larry Westlake]

Launch

One of the free-moulded "Rat" canoes has finally been finished and taken for a few jaunts.
Here's a pic.