Thread: DIY Canoe - Plan advice

My 33 year old fibreglass canoe is about that length, but is less than 800mm wide.

It is extremely stable, but your design would probably have about the same stability in spite of its extra width. That is because the ends on yours are finer, so only a short section in the middle is close to maximum width. Mine has fuller ends so more of its length is close to maximum width, which gives greater stability.

As the canoe gets wider, it becomes more difficult to paddle efficiently, so it might be worth considering making it narrower but making the ends a bit fuller to retain the stability.

Are you planning to paddle it as a double or solo? At that width, paddling solo would be awkward.

900 beam is about the maximum you see.

When trying to survey approximate dimensions for canoes with different purposes I found pages like this on the internet to get a feel for approximate dimensions.
Canoe Buyers' Guide - Paddling.net

You can go reasonably wide with a single if the canoeist is skilled - they won't be swapping the paddling side very often - or if travelling with gear you usually end up migrating towards one of the ends of the boat with the gear in the middle. For example the Chestnut Prospector canoe is a high volume canoe that is well regarded for single paddling

Bill Mason's Chestnut Prospector
Prospector by Merrimack Canoe Company - Paddling.net

It is a little narrower than the 900 though.

I don't mean the Prospector as a perfect model - just that a wider boat can be Ok as a single if it and the paddler are both good. But this is probably well away from the normal level of use of the average OZ paddler.

Best wishes.
Michael

Have you tested the hull for "developed" surfaces yet? How'd those broad strakes look when you did?

Rather then design your own boat, you should pattern it after a known design and make cosmetic alterations, until you understand the nuances of the shapes involved.

What you've drawn in a fairly well burdened "freight train". She'll carry a load and go in a straight line good. If these are the goals of your concept, then you've nailed it. If you'd like a little more maneuverability, maybe an easier to paddle craft, then you should revaluate the profiles and plan of the garboard and broads at the very least.

Thanks Guys.

anewhouse ~ "As the canoe gets wider, it becomes more difficult to paddle efficiently, so it might be worth considering making it narrower but making the ends a bit fuller to retain the stability."

Thanks I hadn't thought of that. I had tried to keep a single arc through the whole thing but will look at fatter ends now to see how it looks.

Boatmik ~ "I don't mean the Prospector as a perfect model - just that a wider boat can be Ok as a single if it and the paddler are both good."

From one of the images that linked to the person paddling did seem to be riding on the side of the canoe. It looked a little odd, however I do plan to be doing tripping with another adult, I think thats the term for taking stuff with you for camping. That as well as fishing.. Mostly on calm lakes or rivers.

Par ~ "Have you tested the hull for "developed" surfaces yet? How'd those broad strakes look when you did?"

I didnt know what a "developed" surface was but searched for the term just then. I had actually done this it turns out. However I was not happy with the result the software I used gave me. I used autocad Lt to produce the plans and then imported it into Blender. I made the 3d model of it in blender by wraping each section point to point, then using the unwrap feature that is usually used for painting models on a flat surface.I know I should have used curves but thought I could fudge it by overcutting. I now know(think) blender does not correctly calculate the unwrap to a flat surface, It just looked so wrong. So I planed to work it out in cad using some math along with it. I dont know how successful it will be but if I over cut a bit then wrap my skeleton frame with it and trim it and then re-import the result into cad I will be able to tell if Blender was giving me a realistic result.

Par ~ "Rather then design your own boat, you should pattern it after a known design and make cosmetic alterations, until you understand the nuances of the shapes involved."

Im not feeling the DIY spirit within you ;-) I was wanting to do it from start to finish )

Par ~ "What you've drawn in a fairly well burdened "freight train". She'll carry a load and go in a straight line good. If these are the goals of your concept, then you've nailed it. If you'd like a little more maneuverability, maybe an easier to paddle craft, then you should revaluate the profiles and plan of the garboard and broads at the very least."

I had to lookup what garboards and broads were also ). That was very helpful, I was wondering a lot about how it would travel. It was the idea to be able to carry a load of camping and fishing gear and go for a trip. I dont think Id trust it dodging bolders or trees so maneuverability was not a major concern. It does still make me wonder how un-maneuverable it would be.

If I put up some more versions would you mind terribly evalulating them. If not could you reccomend some software that evaluates if a boat will track straight V's maneuver well.


Thanks very much for you comments Par, Boatmik and anewhouse !!!

Must admit I am with you on the fun of doing your own design. The Huls software comes with a ton and a half of earlier designs to play with- from catamarans to house boats - fairly old fassioned but seems extremely good at what it does, which is generate the cutout patterns for a spline across a bow plate, 3 bulkheads and a transom with as many chines as you want. Not particularly good at creating a round stem though. Not sure how compatible it is with the other stuff you are using.


Carlson Design Plotter/Cutters

The basic problem with all software packages, particularly the free and low cost offerings is it will generate all sorts of boat like shapes if you play with it, but it will not tell you if the shapes you've selected or drawn are well suited to the goals of the design. Some software packages attempt to address this with primitive VPP and other resistance analyses, but it still can't tell you what you don't understand.

This is where the education part comes in. Unlike the other engineering disciplines, yacht design has a fair bit of black magic, guess work and experience involved. There's only so much a mathematical model can develop, before you have to rely on intuition and abstract concept understanding.

Fortunately, canoes and other small craft are quite plentiful and are literally just what the budding designer cuts their teeth on (studying previous designs). If you screw up and it's a pig (because you ventured too far out on a design limb), well it's only a canoe and you can make adjustments from what you've learned on the next version.

Every designer I know has modeled their first efforts after someone else's well known design. This is principally because they want to have a success right out of the box. They'll learn things from this design and expand their understanding on the next version of the same design.

You can wing it if you like, it's not a lot of materials, effort and money if it turns out she's a bear to paddle or can't turn very well. This is a haphazard approach, but not an unusual one. It's the way I started when I was 12. Though by the time I was 16, I'd learned if I didn't want to get passed, out on the water by other boats of similar configuration, I better start "paying attention" to the successful designs and incorporating the hard learned lessons the designer's of these boats had earned, before me.

In short, you may very well be able to teach yourself how to extract your own wisdom teeth, but the wise prospective dentist, might want to study the subtleties of the procedures, before taking the pliers to your own mouth.

It's a boy thing.

Ok well I have now looked a fair bit at designs and went to something modeled off the prospector but with ply strips.


I'm going to go with this design and see how I go. Like Par has said the materials are cheap for a canoe anyhow and I have enough for two anyhow.

I think that is a significant improvement on your original version.

Just reporting back in for the curious.

I am getting there.. Wired up loosely in this pic.

Making good progress.
What software are you using ?
cheers
AJ

B.O.A.T ~"What software are you using ?"

Autocad LT - (not ideal as its 2D only)

Using Gregg Carlson's "Hulls" myself.
Pretty simple 3-D
Not 100% accurate in the panels it develops.

I am (or have been) in the same situation as yourself - an absolute novice
who wanted to build a boat from his own head, not someone else's. Despite
Hulls' inaccuracies, I've built 5 kayaks from it which didn't let in water, and
performed more or less as expected.

For serious racing, for edge-of-the-world stuff, or for big ticket boats, I'd build
from a 'real' designer's plans. For the other 99-point-something % of my boating,
the whole DIY from idea to 3-D has been more rewarding, albeit at some risk.
all the best.
AJ

strong familial resemblance to Freeship