I paddled my Seda Ikkuma inside the bay, at about 4 kts, in a steady 10 kt cross wind and very light chop. The Ikkuma weather cocks very slightly, as a good design should, and is easy to control directionally with slight leans and slight sweeps.
However, my GPS indicated an increase in speed of 0.1 to 0.2 kts was achieved by deploying the skeg. Without the skeg slight sweeps and leans are required every 4 or 5 strokes, while with the skeg deployed even slighter corrections are required every 20 or 30 strokes. I repeated these skeg up and down trials multiple times with the same results.
The Ikkuma skeg is small, with high aspect ratio, but quite effective. Any drag increase due to the skeg is overwhelmed by the benefit of greater stroke efficiency.
YMMV. Don't know if this applies to any boat and skeg.
The Kayak Wing
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sounds about right|
Posted by: edzep on Jan-27-13 6:24 PM (EST)
I think the "debate" begins when people talk about using skegs NOT for wind, but to compensate for a hull that may be too loose, or for a paddler's technique causing side-to-side veer. Or, in my case, just to coast in a straight line when not paddling -- messing with a camera. Some of us have found that the skegs cause drag and impede speed. I often forget to put my skeg up, after taking photos. I soon notice that the boat feels sluggish.
Posted by: gjf12 on Jan-28-13 12:27 AM (EST)
Using my gps on calm water I have not been able to detect any drag/speed difference with the skeg deployed or not. Perhaps your skeg is very large or you are more attuned to small drag differences.
Faster/less effort with effective skeg|
Posted by: Celia on Jan-28-13 7:51 AM (EST)
At least that is what I have found the few times I have paid attention. The times that I have it more than partially deployed, I am usually focused on other things. IMO, the skeg and drag thing is way overrated as an issue for anyone other than people racing. The keel on my first sea kayak was a lot more distracting than the skeg has ever been (which is not always healthy for a skeg when landing).
Really depends on the hull shape|
Posted by: FrankNC on Jan-28-13 11:39 AM (EST)
Like most racing boats NEED the rudder, many standard kayaks perform better the skeg.
Posted by: Celia on Jan-28-13 2:08 PM (EST)
Yes, it still goes to the designer's intent. My first sea kayak really was intended to work with a rudder even in its stowed position - it was part of how that hull was planned to deal with wind. Since I found the rudder to be a PITA for my own purposes and always ended up taking it up again, that meant a different boat when I decided that I'd rather be living with a skeg. So I got a boat that was designed with a skeg in mind.
Posted by: booztalkin on Jan-28-13 3:48 PM (EST)
My first kayak turned towards the inside edge. It really messed me up because everyone was telling me it was supposed to turn away from the leaned (down) side. After paddling it hundreds of hours (weird thing named Kanoe Latvija), I concluded it had three turning positions, slight, medium, and heavy lean, which turned the boat in, out and in. It did mess me up. I got rid of it.
Sorry, your test proves nothing.|
Posted by: scott_f on Jan-29-13 1:18 AM (EST)
That small margin of difference could have easily been your mindset. Without doing a blind test, that 2.5%-5% difference means nothing. Not trying to be harsh, just looking at this scientifically.
Posted by: gjf12 on Jan-29-13 3:00 AM (EST)
I agree that nothing was proven. However, I tried it enough times to lead me to deploy the skeg in wind and chop if I want to go a bit faster or with less effort.
I agree about a blind test|
Posted by: adbass on Jan-29-13 8:37 AM (EST)
and about the lack of definitive proof, but really...
I would tend to agree, and...|
Posted by: scott_f on Jan-30-13 5:06 AM (EST)
I would say that is a good hypothesis. I'm not sure the efficiency of a skeg has ever really been tested. It would take an incredible amount of resources to really prove the efficiency. There are simply so many variables (paddle style, stroke style, paddler size and ability, skeg shape, hull shape, water conditions, wind, etc). I guess it's reasonable to go along with the experience of someone like Paul Caffyn who agrees that skegs over distance are better (and rudders are better yet), but I tend not to firmly believe anything without testing by scientific method. And even then, a theory is only correct until it's proven wrong. My experience shows that a skeg is more efficient for beginners in high winds because they don't have the skills to cope without an aid to prevent weathercocking, and some boats also have a strong need of an aid to prevent broaching. But when it comes to splitting hairs over 2.5%-5% efficiency, I really don't know. Either way, it's an interesting thing to think about.
Accuracy of gps ?|
Posted by: willi_h2o on Jan-29-13 7:56 PM (EST)
You are probably correct regarding|
Posted by: adbass on Jan-30-13 8:33 AM (EST)
GPS accuracy if the original poster is talking about measurements of "instantaneous" speed, but not if the average speeds were calculated over sufficiently longer distances.
Side to side movement|
Posted by: willi_h2o on Jan-30-13 12:57 PM (EST)
GPS simply won't pick up that very minimal ziggy-zag
But there's no need to measure that.|
Posted by: guideboatguy on Jan-30-13 2:44 PM (EST)
Everything has limits|
Posted by: willi_h2o on Jan-30-13 3:55 PM (EST)
agree, results will vary...|
Posted by: jcbikeski on Jan-30-13 4:33 PM (EST)
Correct, but it's even easier than that|
Posted by: guideboatguy on Jan-30-13 5:05 PM (EST)
Sure enough. All I did was point out ..|
Posted by: guideboatguy on Jan-30-13 4:53 PM (EST)
There is a reason it hasn't been done|
Posted by: willi_h2o on Jan-30-13 7:23 PM (EST)
Not that complicated|
Posted by: gjf12 on Jan-30-13 11:26 PM (EST)
And publishing is not required. Just mount your GPS on the deck and paddle at, say, 4 kts for a minute holding the speed. Then increase effort till speed increases to 4.1 kts, easily done. You will see that a 0.1 kt change can readily be seen, and maintained. In 10 kts cross wind on a lake or bay, you can readily see a 0.1 difference between skeg up and down.
Enjoy the experiment|
Posted by: willi_h2o on Jan-31-13 12:25 AM (EST)
0.1 knot = 0.1 mph
The whole point|
Posted by: gjf12 on Jan-31-13 12:57 AM (EST)
is not navigation, but to verify, at least to myself, a marginal increase in speed to be obtained by deploying the skeg, at least in moderate cross wind.
500ft over an hour|
Posted by: willi_h2o on Jan-31-13 2:06 AM (EST)
Over a 60 minute time frame
No, you don't get it.|
Posted by: guideboatguy on Jan-31-13 11:31 AM (EST)
At very slow speeds - equality|
Posted by: willi_h2o on Jan-31-13 2:17 PM (EST)
Tough to measure yes...|
Posted by: guideboatguy on Jan-31-13 2:28 PM (EST)
... but there's no need to greatly exaggerate distance-determination errors, especially not by erroneous reasoning, just to make this point. And the difference in mph vs. knots becomes very significant when using those values interchangeably to determine distance traveled over an hour's time. Calculation of distance traveled by this method is backwards and inappropriate in this context (it makes no sense to calculate something based on a calculated result if you already have more basic data), but that is what you were espousing, and therefore the difference between these units matters a lot.
Posted by: willi_h2o on Jan-31-13 2:34 PM (EST)
Posted by: jcbikeski on Jan-31-13 2:41 PM (EST)
for a GPS for this purpose if you have a mile course and the GPS is accurate to say 50ft then you have 1% error possible on distance. But the good news for measuring things like skeg effectiveness is you DON'T really need to know the distance at all. If you have a fixed route (say one pier to another) then all you have to do is measure TIME accurately to determine that say a skeg is 2% faster or slower. So measuring is pretty darn accurate -- the problem is now the paddler which will vary by fatique, motivation, etc. For that problem the best you can do is have many trials alternating between skeg or not. The variations in the results will give a clue to how accurate you can declare your final conclusion to be.
Posted by: adbass on Jan-31-13 3:37 PM (EST)
don't forget that weather conditions can change from minute to minute and so represent a factor, other than paddler fatigue and motivation, that will affect the accuracy and reproduce-ability of any measurement.
Posted by: jcbikeski on Jan-31-13 3:41 PM (EST)
the hope on weather/wind is that if you do say ten trials in a row (alternating skeg or not) that the weather changes happen gradually and so you still see a trend. Far from perfect of course.
You never even read what I wrote.|
Posted by: guideboatguy on Jan-31-13 4:12 PM (EST)
I'm not going to go back and illustrate how stupid it was of you to bring up this crazy idea that anything I said is based on what's seen on the display.
I seem to remember these discussions|
Posted by: CapeFear on Jan-31-13 2:19 PM (EST)
I think I remember several discussions of this sort years ago on this site. I remember the gist of it being whether it is more efficient to achieve directional control through edging and strokes, or through use of a skeg or rudder.
Posted by: radiomix on Jan-31-13 3:31 PM (EST)
For this nonsense is the following.