water resistance
i se that this table of water resistance is for kayaks, is there one for canoes?
He said “faster”, not “better” NM
3 Knots
Whenever you read that you have to have some idea how it was measured. I average somewhere around there for a 3-4 hour outing but that’s because I paddle at 4-4.5 knots for stretches and then bob around resting and looking at wildlife and river traffic in between.
Depends on where you are paddling, on the Hudson here I’m interested in covering some distance each time I go out. Would not be happy with such a short boat.
Mike
The same
OK, it’s not better AND not faster. 
Good point
"Average touring pace" may not be the same as “typical paddling speed”.
And as another post said, it’s important to match the boat to the paddler and the intended use, not just look at numbers. My small, non-athletic wife is faster and happier in a small boat that fits her than she was in her previous longer boat. A strong fitness paddler would move in the opposite direction.
Silly argument
There IS a difference in terms and is does matter.
What’s silly is the limited relevance of this tired old argument about short boats being faster at slower speeds. Faster at slower speeds? Makes no sense. More efficient maybe, but who cares about resistance at around 3 knots or less where most kayaks intersect or are very close on the drag curves. The differences are too small to matter. Few would even be able to feel it. Your talking ounces of force in most cases. At 4 knots and up your talking pounds. That matters and longer boats rule.
Not just water resistance
How about wind and waves? There comes a point when extra leverage out at the ends becomes a real issue, especially with the wind forward of the beam.
I’m hearing this from a 21’ ski paddler?
Tell me it ain’t so! L
This ain’t a best/better/ultimate boat thing. Not talking about anything universal. They all have pros and cons. Trade-offs. Balance. More about design intent/intended use really.
If you want to go really slow and are weak/feeble, or are fit and want to aggressively play sit 'n spin in a washing machine - I certainly won’t say go long.
In 2-3 foot wind wave chop I’ll late my 700 over our Pintail any day though. A lot more fun ride. I like to actually paddle in open water, not cork around. In surf, probably the other way around. Someday I’ll get to try a surf kayak and a WW boat. It’s all good.
Ski is a LOT of work in big stuff
Example: my Monday spanking. I knew the wind had come up, wasn’t paying as much attention as I should have to how much it had come up. I’m out of shape and just starting to work semi-hard at getting back into shape, which meant I had exercised pretty hard both Sat. and Sunday (running and then surfing) and didn’t have a lot left on Monday. So I get out on my downwind run, and about when I get to the most exposed part of it, I’m starting to run out of gas. By the time all was said and done, I’d had three swims, one of which took probably 10-12 re-entry attempts before I got up again, and a paddle that should have been around an hour and fifteen minutes took a little over two hours. Why? Because if you’re not moving the ski well, it’s twisting and hobbyhorsing and pointing the bow at the sky and all kinds of stuff that isn’t getting you closer to where you’re going, and every time it gets stopped on the back of a wave you have to accelerate it again. And that’s downwind. Upwind is actually HARD!
Contrast at the extreme other end of the scale: a couple of months ago on a similar day, I paddled my little Wave Witch out to the Diamond Head buoy just for the hell of it. Now, there’s no way a 9’ boat is ever going to qualify as fast, but it was totally unaffected by the wind and moved about the same as it would on flat water. It was kind of fun to be sitting there amid those big piles of water with the wind blasting on me and not be fighting the boat.
If I’m going to be out in big stuff for an hour or two, yes, I want the ski. But as the pace starts to come down from pushing hard to something that’s sustainable for several hours, I have no trouble at all believing that I’d be faster in a shorter boat than a longer one for the same level of effort, and the level of effort I’d be putting out is still quite a bit higher than the average pond paddler.
You have to go really small to see
To see a big difference in speed for touring boats you have to go really small. My blackwater 11.5 is really fast compared to white water kayaks with a top speed of 5.1 MPH and a cruising speed of 2.8 MPH. It’s much longer and much faster than the other boats and I’m strong enough to paddle it at its top speed.
Copare it to a 16 foot touring kayak with a top speed of 6 MPH and you can see a big difference. Once the boats get longer than that I just can’t sustain the effort to keep the boats going any faster than 6. And in all 3 to 4.5 MPH is my reasonable paddling speed for any period of time over an hour.
thanks
to all for the input
Another thing to think about
Nothing scientific here, but I have the sense that if you added a 50 lbs of cargo to a 13 foot boat and 50 lbs. of cargo to a 17 foot boat, the shorter boat would have a greater increase in draft (and wetted surface) and would begin to bog down at speeds of even 3 knots, while the longer boat would be much less affected by added cargo weight.
Silly?
“Longer, skinnier, and lighter is faster with the same motor paddling.”
If the motor doesn’t have much power, a shorter boat can be driven faster than a longer boat. That’s all I wanted to say. Starting point was the water resistance at different speeds. At low speeds shorter boats need less paddling power, if everything else is constant. I’m not speaking about their maximum hull speed.
The initial question was if it’s true that shorter boats can have lower water resistance in speeds up to 3-4 knots, and if this is a typical cruising speed. The answer is yes. If you want to be faster, you need a longer boat, sure.
Factor in beam…
… and you get a bit closer to reality.
To make any real sense you have to add “at same beam” - but even that isn’t enough because a shorter boat with same beam will sink deeper with a given displacement!
You have to think 3D & 4D, not 2D.
Short boats are nearly always fat boats. Fat boats plow, skinny boats glide. Paddle what you want.
I do
I do, and my P&H Vela isn’t fat.
Short and long boats with same beam
Comparison of short and long boats with same beam
(from http://keelhauler.org/khcc/seakayak.htm ).
Speed/knots - 2/3/4/4.5/5/6
(16’x20.625") - 0.96/2.10/3.88/5.22/7.11/12.6
(20’x20.625") - 1.00/2.14/3.77/4.86/6.22/10.3
As you can see, they are within 0.04 lbs (just over 1/2 ounce) of force at 2-3 knots. At 4 knots the difference is still only 0.11 lbs (1 3/4 oz)- but the advantage is to the long boat already, and it increases quickly beyond that.
I can understand someone not really caring about going over 3 knots if they never do while paddling (if you can call that paddling!), but below that there is no real advantage. Certainly not a reason to pick a shorter boat. There are other good reasons, but efficiency of forward motion is just not a factor.
If you really still think there is some serious efficiency advantage, I suggest you download Matt Broze’s drag prediction spreadsheet and plug in some numbers.
http://www.marinerkayaks.com/mkhtml/downloads.htm
Lots of kayaks already on it to compare. The Vela isn’t (and no Sea Kayaker review), but the Neck Elaho isn’t too far off for LWL/BWL (Vela should be just slightly slicker) and here are it’s numbers at the same 2/3/4/4.5/5/6 knots marks as in the example above):
0.90/1.92/3.71/5.62/8.76/14.07
Compare that to the examples above - and again the "advantage below the crossover with longer boats (which again is at close to 3 knots) is extremely small - even when using a 20’ boat for comparison. Barely over an ounce at best point on the curve (around 2 knots or less), and that is at an already VERY low effort range where no one would notice.
Claim your “advantage” if you like, but if you think the longer boats are at any real disadvantage at 3 knots or below I again suggest you check the numbers and think about what the values (particularly under 3-4 lbs) actually mean.
For cruising efficiency/energy saving you’d be far better off using a lighter paddle than a shorter boat. Doesn’t change the pull much (though most lighter paddles are also better designs and do pull better too) but the effort saved on the return is far more than any minuscule drag break you’re gaining with a shorter LWL.
i wish you could paddle
my phoenix pelican, 14’x22" with a lot of flare, maybe 18"wl beam. no not a typical boat but there are a lot of generalizations being thrown out in this discussion.
From the article
"The shorter boat has less drag at low speeds, the longer at higher speeds, as expected."
“Shorter boats have less friction at low speeds, longer boats have less residual drag at higher speeds”
The difference at higher speeds is bigger, sure. But there are much more things affecting speed, as you said already. If you want to paddle fast, you need a long, narrow boat. If you stay within the 3-4 knot range, you also can use a shorter boat. OK?
Less yes - but ridiculously less L
– Last Updated: Sep-09-05 11:44 AM EST –
I'm not saying it's not true - technically it is. I'm saying it's insignificant and of no real use to anyone. The numbers are quite clear on this.
Absolutely you can use a shorter boat - at lower speeds it makes no real difference in effort.
I'm not saying everyone should be in longer boats. All I dispute is the so called advantage of shorter hulls at lower speeds. It's a meaningless technicality that people hear about and think it is a reason to get a short boat. As I said already - there are lots of good reasons to get a shorter boat. This just shouldn't be one of them.
agreed
I’ve got boats from 16’8" to 21’8" sitting on my deck. Up to 6mph I can’t really tell a difference in drag on any of them. Back when I had a 14ft boat it felt the same as the others up to 4mph. It is only at and above “hullspeed” that drag matters. Like Greyak said, there are plenty of good reasons for a shorter boat but hydrodynamic efficiency gains at lower speeds are nominal.