Use of Skeg^

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mclaughlin
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Use of Skeg^

Post by mclaughlin » Sun Nov 23, 2008 8:27 pm

I'm fairly new into sea kayaking and would be grateful if someone could shed some light on the correct use of a Skeg. Is this really for a cross wind since I have heard that its really for use with a tail wind? Are you meant to extend it fully or is there times wind if should be half deployed?

Thanks

Richard

Chris Bolton
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Post by Chris Bolton » Sun Nov 23, 2008 9:01 pm

Think of the wind blowing sideways on to your boat. Simplifying a bit, the bow usually has a bit more grip on the water than the stern, so as the boat blows sideways, the stern moves faster, so you turn upwind.

If you put down a bit of skeg, the stern has more grip and the boat goes straight. If you put down the lot, the balance goes the other way, the bow is blown sideways faster and you turn downwind.

So, generally, no skeg to go upwind, some to go cross wind, most of it to go downwind. If you put a lot of weight in one end of the boat, it sits deeper in the water, which can change this a bit.

With some boats, you can get the weight in the ends just right so that you don't need a skeg at all, which saves a lot of hassle - but since skegs were invented, most designs aren't balanced as well as they used to have to be.

Chris

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Erling
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Post by Erling » Mon Nov 24, 2008 7:17 am

This flash lesson is an excellent illustration to Chris's excellent explanation:
http://www.atlantickayaktours.com/pages ... g-1A.shtml
The older I get, the better I used to be.

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soundoftheseagull
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Post by soundoftheseagull » Mon Nov 24, 2008 9:17 am

"A picture paints a thousand words"
Once again a great find Erling hope your all well over in Norway
Regards
Dave
Dave

Rockpool GT

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PeterG
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Post by PeterG » Mon Nov 24, 2008 1:00 pm

You can tell when you have the skeg just right because the boat takes up the heading you want, no edging, no steering, just the correct heading. Adjustment is in millimetres, if the boat is turning upwind you need more skeg, if tending to bear away less skeg.

I paddle an anas acuta, it needs most skeg with wind on the rear quarter force 5 and wind blown chop. In bigger waves you need less. On other headings you need less. In very strong winds you need less, I am not sure why this should be as it doesn't seem logical with the need for skeg increasing up to this force.

Every trip it is different sometimes no skeg is needed just when you would expect it to be right down. Subtle effects of wind, waves and tide. If you try racing someone, the skeg does reduce speed and turning rapidly to surf down a wave you will regret forgetting that the skeg is down, so in general the less the better.

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Post by Owen » Mon Nov 24, 2008 1:29 pm

PeterG wrote: I paddle an anas acuta, it needs most skeg with wind on the rear quarter force 5 and wind blown chop. In bigger waves you need less. On other headings you need less. In very strong winds you need less, I am not sure why this should be as it doesn't seem logical with the need for skeg increasing up to this force.
I think this is because when it gets rougher, the waves get bigger and when your in the troughs your sheltered to some extent. Also when your on the crest of the waves its easier to correct your heading; your probably doing this without even thinking about it.

I paddle an Anas Acuta but without a skeg and, yes when the winds on your rear quarter its a bit of a handful. The Anas Acuta has a fair bit of rocker - for a sea kayak - this is great when playing in amongdt the rocks but doesn't help when being spun around by the wind.

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Robert Craig
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Post by Robert Craig » Mon Nov 24, 2008 6:33 pm

In very strong winds you need less, I am not sure why this should be as it doesn't seem logical with the need for skeg increasing up to this force.
I too have noticed this effect.

I believe it's because I paddle slower in a stronger wind.

The subtlety is that the centre of pressure of the underwater bit of the kayak moves according to the speed of the kayak. With the kayak stationary, the cenre of pressure is in the middle: the faster the boat goes the further forward the cenre of pressure moves. That's why a white water kayak is unstable in yaw: and gets more unstable the faster you paddle.

The skeg is deployed to change the shape of the kayak so that the centre of pressure of the bit in the water is under the centtre of pressure of the bit in the wind. That way there's no turning force from the wind. The faster you go, the more skeg you need, so's to compensate for the centre of pressure of the rest of the kayak moving forwards.

So there are two effects: first of all the stronger the wind the more the turning; then when the wind gets really strong you slow down, decreasing the turning effect.

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scotty
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Post by scotty » Mon Nov 24, 2008 7:54 pm

I have paddled a plastic capella for a couple of years and am still quite skeg dependant in everything apart from headwinds. I can only ever have to much skeg down if the kayak is loaded with weight to the rear,with normal loading or empty it only reduces weather cocking when fully deployed,even feels better when surfing downwind with it down. Is this something i will grow out of or is it kayak specific?

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Robert Craig
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Post by Robert Craig » Mon Nov 24, 2008 8:07 pm

I'd claim - and I'm sure I'll be shot down - that this effect depends on the boat, not the user's skill.

For any one combination of wind speed, wind direction, and boat speed, there's an amount of skeg which makes the kayak neutral. The only skill is in finding this amount.

Yes, one can compensate by a bit of edge, a bit of extended paddle, a bit of sweep stroke. But none of that is seamanlike, and any of that slows you down. Sea kayaking is about journeying on the sea, with minimum effort and maximum safety.

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Post by RichardCree » Mon Nov 24, 2008 8:15 pm

Sea kayaking is about journeying on the sea, with minimum effort and maximum safety
if thats your thing.

i paddle bloody hard and sometimes its not that safe (in other peoples eyes), but thats my choice. The majority of my paddling is playing, rockhopping and coaching, journeying is just a tiny part of where i get my enjoyment from.

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Douglas Wilcox
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Whatever floats your boat!

Post by Douglas Wilcox » Mon Nov 24, 2008 9:06 pm

Much as I usually agree with Richard, I have to say I am firmly with Robert on this one!

Image
Sea kayaking is about journeying on the sea, with minimum effort and maximum safety.
Douglas :o)

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Jim
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Post by Jim » Mon Nov 24, 2008 9:28 pm

Whilst I admire Roberts dynamic shift of CLR explanation I just can't let him get away with saying that edging is not seamanlike!
It's pure, it's native, nothing could more seamanlike than handling a well balanced hard chined boat with no skeg and just edging.

That's not to say it doesn't get annoying or sore after a few miles....

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Mark R
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Post by Mark R » Tue Nov 25, 2008 6:52 pm

I don't think I'm normal, but ... I paddle with skeg down all the time unless I am paddling among rocks/caves/tight places (which is a very small fraction of my paddling).

I honestly feel like I can't paddle in a straight line without it.
Mark Rainsley
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Jim
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Post by Jim » Thu Nov 27, 2008 10:52 am

Mark R wrote:I don't think I'm normal, but ... I paddle with skeg down all the time unless I am paddling among rocks/caves/tight places (which is a very small fraction of my paddling).

I honestly feel like I can't paddle in a straight line without it.
Maybe your loading regime leaves the boat trimmed by the head all the time so the skeg balances it out? Or maybe you just paddle so fast upwind that the skeg grips the water harder than the wind can grip the bow?

mclaughlin
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Use of Skeg 2

Post by mclaughlin » Thu Nov 27, 2008 10:30 pm

Thanks for all the responses, obviously a good topic for debate. Excellent picture Doug.

Cheers

Richard

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