Designing a 9 foot canoe

I would like to design a 9 foot canoe with about a 35 inch width. Have any of you done this?



I see most of the small pack type canoes as miniature racers and instead want it to be more stable and hold more weight.



At the same time I want a light weight canoe, not like the “floating trash can” cheapo kayaks.



Any advice?

Well,…
It’s your design, correct? So what do you propose?

pic
http://pad3.whstatic.com/images/thumb/d/de/Build-a-Plywood-Canoe-Intro.jpg/670px-Build-a-Plywood-Canoe-Intro.jpg

I
I have given a few guidelines, just looking for more wisdom before I start.

To be real
about your proposed dimentions,at 9’ with a 35" beam you are looking at a floating tub. The same with any 9’ kayak.

look
out…look thru:



http://www.thecheappages.com/boat/bolger_sbj.html



http://councill.home.mindspring.com/sbjournal/sbjindex.htm



https://www.google.com/webhp?ssrp=1#q=small+boat+journal



If Bolger and friends stopped short of a 9’ canoe there should be something in a tugboat or frigate near 9


Why so short?

– Last Updated: Jan-15-15 6:34 PM EST –

I wonder what your reason is for wanting such a short boat. You may have a good reason, but I suggest that you make sure you understand how slow such a boat will be, and if that's okay with you, great.

Years ago I occasionally paddled a "duck boat" that my dad built back in about 1960. It was made of quarter-inch plywood and was probably similar to many plywood canoes. I wish I could remember its length. I think it was 10' but I'm not sure. I didn't remotely understand in those days what the reason was that it moved through the water very nicely with minimal effort as long as the speed was very slow, yet no amount of paddling effort would make it go as fast as I was used to going in a regular canoe. I wasted a lot of effort trying to make that boat go at a normal speed, not knowing that it was impossible. You should know that a 9' canoe won't go any faster than about 4.5 mph no matter what you do, and the practical maximum cruising speed will most likely be about 3.5 mph. Your fastest reasonable cruising speed in a 9' canoe will be about the same as that which people in boats 12' or longer can do with very minimal effort. If you only use the boat on a little pond where you simply can't go far, a 9' canoe may be fine.

I currently have a sweet little rowboat (double-ended like a canoe) that's 12' long. It's lively and a joy to row, especially on small waters, but as far as speed goes, it "hits the wall" at 5.3 mph, though with great effort it will go 5.5 mph. The maximum cruising speed is 5.0 mph and a practical long-distance cruising speed is about 4.5. If it were paddled instead of rowed, the maximum cruising speed would be a bit less. What's my point in telling you this? Figure out how much farther one goes for each hour of cruising in a 12' boat compared to a 9-footer and it becomes clear why that little bit of speed difference matters quite a lot, unless you have nowhere to go.

I only weigh about 165, and under no circumstances that I've experienced would I consider a canoe less than 12' long (specialized whitewater boats could be an exception, but I don't do extreme whitewater). Again, I'm not saying you might not have a perfect application for a 9' canoe. I'm just hoping you know what you are getting into, as far as traveling efficiency goes.

Oh, be aware also that a lot goes into stability besides just the width, and that from a given starting point, adding length has much the same effect as adding width. Have you paddled any of those pack canoes that you think are built like racing boats? Not knowing anything about your size or experience, there's no way to be sure about this, but you may find that with a bit of time to get used to them, they change from something that feels tippy to something that has you feeling confident.

Paddle some successful super-short
canoes, if you can find them, and see if that is really how you want to go.



You don’t need to add width to get stability. Adding length can do the same thing. Think about what that length does to steady the hull.

Hmm…
Not sure I agree with that. If you have a 30 inch wide, 10 foot canoe, and a 30 inch, 15 footer, I think you’ll get a lot less extra stability that you would with a 35 inch wide, 10 footer.

No one is saying anything like that.
No one is tying to pin down the specific relationship between increased length and increased width. No such linear relationship has been stated or implied. You may be right about the specific example you have chosen to make your point (but even in that case it will also depend on the overall profile of the hull, both as seen from the end and from the top or bottom), but that doesn’t change the fact that for two boats of the same width, the longer one will have greater stability and greater load capacity, just as the OP is looking for. Given the OP’s idea that pack canoes are similar to racing boats, it seems likely that he hasn’t actually paddled one, and the idea stated by EZ and myself may be worth pointing out. The main point is, choosing a boat that’s exceptionally short and exceptionally wide (for a solo, anyway) won’t provide anything that can’t also be provided by a more versatile boat that’s a few feet longer (unless the boat does not need to be paddled far, and the user needs that short length for some other reason).

Perimeters

– Last Updated: Jan-16-15 8:36 PM EST –

Speed is a function of length, conditional on the paddler having the horsepower to drive the hull. The rough formula id the square root of the length, in feet, multiplied by 1.55 yields potential, two wave wash forward speed in mph. the OP's 9 footer will top out around 4.5mph with rational cruising speed, the point where wave making resistance starts to become a factor, .6 of that maximum, a little under 3mph.

Tracking, or course keeping, best correlates with block coefficient, but length to width ratio is a useful approximation. Most hulls that track well have L/W ratios between 6 and 7, the op's proposed hull has a L/W ratio of 2.74, guaranteed to provide a nice view of all sides of the lake. There are things a designer can do to improve tracking, involving large skegged aft parts that heroically increase skin friction, significantly slowing the hull and also compromise maneuverability.

It's not likely to paddle well or sell well, but who knows? It's helpful to think outside the box occasionally, but in this case the problems bubble up pretty quickly.

maybe what you really need
Is a rowboat.



http://gaboats.com/boats/whitehalljr.html


short canoes
I paddle an eight foot, 4 inch long canoe on whitewater with a beam a little less than 28".



There are ways to make a canoe that short go where you want, but they require more focus and attention and don’t make for the most relaxing way to paddle flat water.



Apart from the speed and tracking limitations of the short length, a midships beam of 35 inches is quite wide for a solo canoe and will make achieving an efficient stroke, or executing cross strokes considerably more difficult.



If you don’t care about going far or fast your design parameters might work fine, but I would agree with trying out a short, fat canoe before you decide to build one, if you haven’t already done so.

Any advice? Yes. It would be . . .
. . . a crappy canoe for any purpose. A small pig. Almost a coracle.



Consider an Old Town Pack canoe. They are wide and stable and fairly light. Popular for decades. Not a serious paddler’s canoe, but very satisfactory to many recreational canoeists and fisherfolk.


You’re right…
a lot depends upon the hull shape. I just think that you have to add a lot of length to gain a whole lot in stability. But I agree with everybody else that adding the length is going to give you a far better boat than widening a really short boat.

Or,
The OT Pack catalogs at 33 if memory serves, not worth looking up as OT is pretty productive with the keyboard in that regard; the published number ~worthless. If the boat must also be light, compare dimensions and weights from Adirondack Canoe & Kayak, Hemlock, Hornbeck, Slip Stream and Swift C&K for hulls between 12 and 20 lbs, 10 and 13 feet.


I would agree in general…
regarding OT’s published “specs” but my OT Pack did indeed weigh just that - 33#. Their fisherman version is noticeably heavier with its bulky barcalounger seat and other accoutrements.



Mine is an older version that came with but one thwart. I use this boat for pond photography but wanted a bit better performance out of the little tub. I made new slender thwarts and moved the seat forward where it should be using an Ed’s contour. I then narrowed everything by 7%. Canoe paddles nicer for me now and still weighs in at 35#. Initial stability took a minor hit but its still plenty stable at a standstill for my photography.


Nine foot pack canoes are not unheard of
See the Hornbeck 9 footer and note the width http://www.hornbeckboats.com/boats_trad_09.php

35 inches wide in ANY boat is an unwieldly width and would call for a monstrous paddle that even if light has considerable resistance due to the length of the paddleshaft.



Flare enhances stability too. I urge you to look at all the Hornbeck boats to see hou they incoorporate flare.



Hull shape is the dominant factor in stability; not width or length



Avoid an abrupt turn of the bilge… In any width boat such a feature dooms the paddler.




had me a 8’x27" canoe,
definately a ww boat. Slow on the flats, slow to attain thus making it hard to make it into play features, never took it out on big water, did fine on class II-IV creeks, It was what I would describe as twitchy. Kept you on your toes, like paddling a cork. It became even more so when I jacked the saddle up 4 or 5" to help with my bad knees. It promoted a cab forward style of paddling. Meaning I got in my swim practice if I hit a rock without my weight forward in the Taureau. My problem was I had to get my center of gravity up real high to have any comfort level in the boat. I probably paddled it on a dozen runs in wv before I figured it was time to sell it- paint creek, upper mill creek, upper new at medium and low flows.



A boat that’s uncomfortable is a boat that doesn’t get paddled. I sat in a “Ledge” when it came out. I knew instantly it wasn’t for me. I can’t get that low anymore. Bad knees have me limping around even on a good day on dry land.



http://www.esquif.com/en/whitewater/taureau/

Reason
The reason for the 9 foot design is that I’d like to take it to Minnesota where boats less that 9 feet ned no registration and I don’t want to pay them off just to have a little fun.



I have a collection of small canoes/kayaks and just don’t want to get numbers for them all.



I realize it would be a little slow to paddle but so what? If I wanted speed I’d build a small airplane!



I appreciate any comments about things like hull shape, deck design, entry lines, seat height and type, etc.



I plan to build as cedar strip/fiberglass which has worked well for me in the past since they turn out very beautiful and still are fairly light to carry.