My son has a waterproof hiking GPS. I wondered what it would say about my kayak. I have a Necky Zoar Sport; it is 14' long and 25" wide. It is a bit of a barge, but that's okay.

My maximum speed (what I could maintain for a few minutes) was 5.1mph. Fast (that I could do for 20 minutes) is 3.9, slow (that I could do for a few hours) is 3.1, and minimum (just fast enough to maintain direction) is 2.6.

I found the tight grouping to be surprising; I expected fast to be 50% more than slow, when it is only 25% faster. A 3 mile trip, the first 20 minutes at fast and the rest at slow would take 53 minutes. That is exactly what I have actually done, so it confirms my GPS. BUT, doing the whole trip at slow would only take 58 minutes. 5 minutes longer, but I would be a great deal less tired.

Does this make sense, or it there something seriously wrong with my methodology?

I did the same in a fiberglass CD Solstice SS; 17.5' and 21" wide. It is much nicer to paddle and feels much faster. But my speeds were 6/4.3/3.8/3.1. Slowest speeds are 20% faster; faster ones only 10% faster. I expected much better than that, considering how they felt.

Any wisdom would be appreciated.

all looks about right to me

All looks about right to me

agree

That sounds pretty consistent to me. Paddling slow or fast is NOT like running or biking slow vs fast. There is a lot more friction and drag involved when on the water moving a large object with a lot of contact with that surface.

Compare the two…

… at a 10 mile race pace and see how far ahead you’ld be in the Solstice.

What ?

http://www.google.com/#q=bicycle+power+output

Your numbers are for your personal curiosity.

Are your numbers like our numbers. Off course....we are not Olympic athletes nor top grade paddlers. There are faster and slower kayak hulls but your are uh representative.

But this glosses over understanding how small fractions of speed over a 10-20-30 mile course yield gross differences in energy consumption over energy available.

Additionally, the Solstice probably has a sweet spot yielding lower energy consumption/higher average speed over 10 miles than a 4 part 'methodology' reveals.

I have a Titan said design for long distance touring. The hull wants to go X in Y conditions n if I of long distance strengths want to go Z (+ or - X) then I am pissing into the wind n will go back to X.

There are a coupla paddlers herein with similar hulls running 2-3 mph faster than my 5.7.

If we all get into the shorter hull we may see similar 'test' differences but over 20 miles ....energy consumed may be complete at 11 miles.

Is this found in your data ?

Skin friction and wavemaking resistance.

Drag from skin friction increases fairly linearly with speed but as speed increases you reach a point where wavemaking resistance comes into play which greatly increases drag.

There is a good description at http://www.oneoceankayaks.com/kayakpro/kayakgrid.htm

Thanks for the help

Very Interesting!

According to the chart, total resistance doubles each time you go a knot faster. Presumably that means you have to work 4 times as hard to go 4.5 knots as to go 2.5 knots. That is pretty much what I found.

5 years ago I went on a 12 mile trip in the Everglades. Now I struggle to go 6 miles in a better kayak. That had me bewildered, but now I realize that I am going much faster now, so I actually use more energy (and in a shorter time) so it makes sense.

I wish that company had a wider variety of widths; I would like to see a chart on how that affects resistance.

Thanks.

Kayak Foundry

If you want to play with design/speed/efficiency, Ross Leidy wrote this design program and has incorporated stability and drag calculations.

http://www.blueheronkayaks.com/kayak/index.html

speed

Kayaks are also all displacement craft, they can not plane - not enough power. So are limited to the speed length ratio. Roughly the square root of waterline length times a multiplier usually around 1.2 to 1.4

Bill H.

My cycling GPS

Has the added advantage of telling me how much elevation gain or loss I have accrued. Guess what? Over a six-mile paddle on flat water I usually climb about 850 ft. and then lose the same amount of altitude, give or take a few feet.

Now talk about funny numbers…

If

The GPS HAS Blue charts with bottom contours n depth reading, a tidal bay is explorable around over n alongside bars holes M flows.

Perception of the bay as FLAT will change after paddling these routes. What was flat becomes a highly varied surface in altitude n texture.

Mine is the cheapest

simplest Garmin cycling GPS unit (discontinued now). I doubt it had any fancy software that takes into account bottom contours (it's supposed to be used on the road). How it tells altitude is a mystery to me, but it certainly doesn't work right.

BLUE CHARTS

Were expensive but Gar lowered to $ 100