waterline vs. paddler weight

As a small paddler, I have wondered if a longer waterline is more efficient than a shorter. Longer boats flow thru smaller waves if you have enough engine. Shorter boats tend to behave as a cork,

going up and over verses thru.At 3.5-4.5 kph is a longer

boat really that much more efficient? Talking about

< 130 lbs with gear & 14’ vs 17’. thanks.

I have a boat that at 230 mlbs, I am
like a cork in. It doesn’t even know I’m there.It does a fine job straight into or out of small waves but gets spooky if they are quartering. It has a 17’ waterline,but it is a canoe.

Overall Volume Counts for a Lot
Too much volume is hell to paddle on a windy day regardless of how long it is.

Personally I would pay more attention to the maximum recommended load than length.

design displacement

– Last Updated: Jul-13-08 8:35 PM EST –

is also a factor: paddler weight + gear weight + boat weight; too much more or too much less than the boat's design displacement, and the boat's performance may not be optimized. Not all manufacturers make design displacement data available.

Also useful is information from the designer (i.e. the "design statement") on what type of paddler the boat is designed for, as well as how and where the boat is intended to be paddled.

Ultimately, it's how you "feel" padding the boat, but objective info can't hurt.

To my understanding …

– Last Updated: Jul-13-08 11:59 PM EST –

.......... a boat will displace the exact weight of water , that the gross load is equal to , when at rest .

Given two different canoes (kayaks shouldn't be any different here) , and each model weighs the same theoretically , add the same payload to each (paddler/gear), and the "cubic inches" of water each displaces should be exactly the same , by my understanding . So weight is weight , no getting around that here . The cubic inches of water that must be displaced for the canoe/yak as it moves through the water are the cubic inches , no getting around that here either .

Given the same paddler w/the same paddle (power) , this becomes an equivalent as well . So what makes one hull design more efficient relative to speed in a straight line , than another ??

I believe it has to do with "how" those cubic inches of water are displaced while moving (ie., the design shape of the hull) . I know of two forms of drag , parasite and induced , and believe how the canoe or yak hull deals with these is also a big factor .
I don't think induced drag could be countered in any noticable way for a noe/yak , but parisite drag certainly should be able to be countered by design . And I believe the cross sectional of the hull would be the greatest factor in the management of drag , making the longer , but narrower hull have the least total drag .

I think this drag works both perpendicular and linear to the reletive direction of the hull as it moves through the water , which when combined equal the total resistence in the opposite direction .

I picture a wide V going through the water , and then a much narrower V . I see lines of drag coming off each V shape in a perpendicular direction .

data point

– Last Updated: Jul-15-08 8:41 AM EST –

A few years ago my 5', 120-lb wife replaced her Avocet RM with a Tchaika Pro -- 2' shorter, but also narrower, lighter, and with lower decks. She found it much easier to paddle at her relaxed pace, and more comfortable because there was less boat to work around.

The problem for smaller paddlers is that most shorter boats are also proportionally wider and deeper, and that has a huge negative impact on efficiency for a small person.

For reference, you might want to demo something like a composite Necky Eliza -- it's a 15' boat specifically desgined to be efficient at moderate speeds with smaller folks.

From the Necky site:

"A little understood phenomenon in our industry is the balance between speed
and efficiency. For years smaller women with less physical power have
been placed in longer kayaks under the notion that longer hulls are faster. It
is true that among hulls of similar design the longer one can be pushed to
higher speeds. In fact strong paddlers can benefit from that potential when
sprinting to catch waves, fight current etc. But this benefit is lost on smaller
paddlers who do not have the strength to drive these longer hulls.
The truth is that longer boats offer little to no advantage at touring speeds,
which for the vast majority of sea touring kayakers, rarely exceed 4 knots.
In fact drag data among many kayak models illustrates that shorter boats
often have less drag at these speeds. Add to this the effect of wind and
waves and a small paddler can find themselves struggling with a kayak that
is just too much for them to handle. Where’s the fun in that?"

"While not a fast kayak by design this is an exceptionally easy boat to paddle
up to 4 knots, which combined with its great manners in heavy seas and high
winds, make it far more efficient for smaller women. In testing, when we
put women in this kayak they were at the front of the pack."

There's also the QCC Q10X -- similar size and design intent, but a very different style. Someone here said that his wife was faster in it than she had been in her bigger boat.

Quite right!
"The problem for smaller paddlers is that most shorter boats are also proprtionally wider and deeper, "

Much worse than that, majority of such “short boats” are actually not open water kayaks. They’re lake barges, with hull shape to go with such design philosiphy.

I paddle a 16x22 Valley Avocet. It’s too big a boat for me (I’m only 110 lb and strength accordingly). It has ok speed as long as I keep it up there. But acceleration is sluggish. So on long trips, I often end up being the “loner”, paddling my own pace, sometime in front sometime behind (more often). For I found the constant small speed variation to stay in “group formation” takes a lot of energy out of me.

So far, I hadn’t found a shorter boat that accelerates quicker but still have the same cruising speed as the Avocet (at 3-4 knot). So I’m stuck with it for the time being.


– Last Updated: Jul-14-08 1:15 PM EST –

The boat weighs more than half of your own body weight -- that's a lot to keep having to accelerate.

The new Avocet LV is only a bit lighter, but it's significantly narrower and lower.

From the Valley website:

Avocet LV
Lenght 15'11" Width 20.5" (52cm) Depth 11.5" Weight* 45lbs

"The boat many smaller people have been crying out for. Despite popularity of the Avocet amongst smaller paddlers, the really small still felt they didn't get the most our of it until loaded. Enter the LV. Not just for volume but also scaled to fit. A genuine small person's kayak"

light paddlers
are good candidates for s&g, wood or skin kayaks as there are so few ultralight low volume kayaks for 100lb paddlers. CD Raven is a good choice for a 100lb paddler as it’s cheap and VERY light. Nothing like acceleration. Pygmys Osprey13(13’x22") is just long enough to do fine at 3.5mph paddling and is very stable for a nervous paddler, both under 30lbs.

Nice handle, nohiney
130 lbs including your gear is quite light. I’m 110 withOUT gear, and I’d still prefer a 17’ kayak over a 14’ one. But only if the 17 footer were not a wider, taller boat.

Most of my paddling has been with 16.5’ sea kayaks. On one vacation, I rented a Piccolo (13.5’, 20.5" beam, low deck) and was pleasantly surprised at how little effort it took to paddle it at my normal paddling speed. Felt like NO effort, actually. Then when our group tried to catch up to some dolphins, I felt like no matter how quick my cadence, I could not get that boat to anywhere the speed I could get for similar effort in my 16.5 footer. So the tradeoff was, would I want to get no-effort cruising at the price of higher top end when I gave it more gas? My answer would be no; others may disagree. Hey, I like to think there is a payoff for becoming stronger.

Now that I have in fact bought a 17.5 footer, so far it looks like my normal speed is the same as with the 16.5 footer. It’s a tad more of a push to get it going but (as you suggested) if I drive it hard through choppy water it just keeps steamin’ ahead. To me, the real questions will be (a) how does it handle with 80-90 lbs of gear added, and (b) how much more difficult will it be to turn it in high wind? I don’t have enough experience in it yet to answer those questions, but so far so good.

If I didn’t ever want to take long camping trips, I’d have stuck to 16.5’ kayaks, but the need for more cargo room has me trying the longer boat. Time will tell whether this was the right decision.

Avocet LV
Sounds very appealing. I’ll have to get my hands on a demo to see for myself… :wink:

thanks all for info
As it stands, I am paddling A montauk, but as the weight tells, I don’t sink it far enough without

turning into a slight gear hauler. I use water jugs

to trim,but it’s sensitive to front-rear. Thanks to all who gave good objective info. Yes, the handle fits

and I have trouble with bike fittings too. Sometimes

to the point of hilarious.

This site is way better these days
in terms of addressing these queations. Probably the best thread on this I’ve read here. Very good, and accurate information. The more folk understand (and it’s not super tough stuff to grasp) the better their equipment match and enjoyment.