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
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.
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.
Fee yes, numbers no
You don't have to put registration numbers on your canoe when registering it in Minnesota (people tend not to believe me about this, so I refer you to page 6 of Minnesota's current rule book). All you need is Minnesota's registration decal. Also, the boat just needs to be registered *somewhere*. It doesn't have to be registered in Minnesota, so that leaves you the option of registering it in your own state instead.
I understand the gripe about paying for registration, but saving a mere $8 per year wouldn't be enough to make me choose a design that performs poorly ($8/year is 15 cents per week, which is less than you can pick up off the sidewalk on any given day). I know it's the principle of the thing, but at least be aware of the registration options above.
Amen…
I’d forget principles and pay the $8 rather than trying to have “fun” with a 9 ft. canoe.
Already
I already have other canoes registered that I could use, a 17’, 19’ and others smaller.
If I were to register them all to use in Minnesota I would have 8 canoes/kayaks to do.
Plus I am looking to the challenge of doing all that I can with 9 ft.
I also want to build a 13 ft canoe that is extra wide, perhaps about 40 inches to handle rough lakes, yet fit in the bed of my pickup.
Rough lakes, width, paddling method
Okay, no more worries about length from me.
I'm not a boat designer by any stretch of the imagination, but I'm thinking that for rough lakes you might consider one with a hull that is rather rounded in cross section. As my screen name implies, one of my double-ended rowboats is an Adirondack guide-boat, who's profile as seen from one end is very rounded and broadly flared. The boat's "footprint" in the water is a lot narrower than its overall width. I routinely take that boat out in waters far more rough than what I or most people would do with a solo canoe (though much of the trouble in a solo canoe at those times is the strong wind, something that a rowboat handles with comparative ease). Even with a height amidships of only 12 inches, this is by far the driest open boat I've ever used. Some of the reason that boat feels secure in big waves is the low seating position (about five or six inches off the bottom, I think), but a lot of it is the rounded hull. A rounded hull profile means the hull is not all that stable "as it sits there" (people usually call this primary stability), but it also means that the water can tilt beneath it and it doesn't get rocked back and forth. As far as the seating arrangement goes in rough water, I'm not sure a high seating position would work so well in a canoe, but kneeling certainly would.
My other double-ended rowboat is smaller than the guide-boat, with a most peculiar bottom profile having reverse curvature each side of center, creating a sharp chine on each edge. It's not designed to have low primary stability like the guide-boat, but the primary stability is low on account of the overall small size of the hull and the fact that (for someone of my weight) it's easy to lift one chine completely out of the water, so it also does quite well in chop.
Pictures showing the hull profile of these boats would not be hard to find online.
One of my canoes (Novacraft Supernova) has a bottom profile that's quite rounded, and though I've only used it as a tripping boat on rivers and for whitewater, I think it would do well in rough waves on a lake, if not for the fact that it's also my least wind-friendly canoe (I probably never will try it in big lake waves on account of the wind issue, at least not intentionally).
If not in rough water, a rounded hull profile (and narrower "footprint") would still be faster and more efficient, but it sounds like that would not be a design goal for you.
I had one final thought on width. My double-ended rowboats are very wide, I believe the guide-boat is 38 inches and the small boat is 36 inches across at the widest point (width of the hull itself, minus the gunwales would be a couple inches less). At that width, solo paddling either boat with a single-blade paddle would be out of the question. Do you use a double-blade paddle or a single? A double-blade would make paddling such a wide boat do-able. If you are a single-blade paddler, I still agree with those who've suggested you try a really wide solo canoe before building one.
extra wide 13’ canoe
I had one of those. Just to back up what GBG said, width doesn’t necessarily = stability on rough water. My 14’ x 28" solo canoe with shallow arch bottom is far more comfortable on wind waves than that 13’ x 39" with flat bottom.
At the risk of being redundant, I also agree that at under 9’ you’d have much better performance rowing a guide boat or “Whitehall” style.
paddle
I generally paddle alone with a double blade.
I have a small 11 ft X24 inch solo canoe but have to sit flat on the floor to keep it upright. It is very fast though and will go as fast as I can crank the paddle.
Stability
In case you are unaware stability increases as a cube of the width(all else being equal) so your proposed 35 inch wide canoe will have more than three times the stability of a 24 inch so it may be a bit of overkill.
With regards to speed you should easily reach “hull speed” in a 9 ft canoe so I would suggest a prismatic coefficient around 0.65 to give a higher top speed.
There is a free design program you might want to play with at http://www.blueheronkayaks.com/kayak/software/software.htm
It’s meant for sea kayaks but you don’t have to build the deck.
need
I need the width for flotation since the canoe is so short.
also
also when you paddle in a swamp or shallow river it’s nice to stay shallow with the hull.