"Paul Stivers" wrote in message
...
I'm new at sea kayaking. See my post last night titled "Greenland boats
for big guys."

At Jon Walpole's excellent site
http://www.cse.ogi.edu/~walpole/kayaking.html I was struck by the fact
that most of the boats in the photo gallery have upturned ends and no
rudder. These are the obvious (to me) visual attributes. I think a
couple of additional attributes are a tendency, on average, toward more
rocker and lower deck, than the American designs. I would have referred
to this as the Greenland design until Brian corrected me. Maybe the
better term is British design.

I know many of the owners of the boats in the photos are experienced sea
kayakers. Probably none are novices.

I'm wondering about the advantages and disadvantages of the British
design on average, relative to the American design. Here's my thoughts,
organized by British attribute, gleaned from various reading. Anyone
care to correct my impressions, or elucidate further?

More rocker.

Adv. More responsive to leaning and paddle strokes.
Disadv. Less forgiving of unintentional variation in body position and
paddle stroke.
Disadv. More prone to weathercocking.


Just a few thoughts on this. And these are just thoughts since, after
about 3 years of kayaking, I too consider myself a novice. I have limited
experience in test paddling boats designed for use with a skeg and have done
some reading on the subject and have read similar discussions in this and
other forums.

Weathercocking: The tendency for the boat to turn into the wind. While this
is often referred to in the negative, it is not necessarily a disadvantage.
It seems to me that it would be nearly impossible to design a boat that is
not influenced by the wind in some way. The choice, by design then, is to
design the boat so that it does tend to turn toward the wind. If your
intended course is into the wind, then this weathercocking would be an
advantage, would it not? This is where the skeg comes in. Contrary to what
many believe, the skeg is not intended to increase tracking directly. It
does so indirectly by countering the boats tendency to weathercock. As you
lower the skeg, the wind's influence on the stern of the boat is decreased.
On a well designed kayak, a fully deployed skeg, by increasing the
resistance to the wind at the stern so dramatically, would change the boats
tendency from turning into the wind to turning away from the wind. A
partially deployed skeg would induce a partial change in this tendency. So
how much skeg you deploy depends on the course you wish to paddle. No skeg
keeps you paddling into the wind, which is a good thing sometimes. Full
skeg should keep you paddling with the wind and in between should allow you
to paddle sideways to the wind or at different courses relative to the wind
depending on degree of deployment.




Upswept ends

Adv. Easier to roll. Boat is less stable upside down in the water.
Adv. Bow cuts through waves rather than punching through.
(Are there other advantages of an upswept stern? Cuts waves that
approach from the back?)
Disadv. Upswept stern is prone to weathercocking. Though a skeg can
largely mitigate this.

Well. That's the idea, I think.

Everyone who reads this, if I'm wrong about this, please fill in for me.
I'm just trying to help but I certainly don't want to be putting forward
grossly inaccurate information.

Cheers!

DV

"Dave Van" wrote:

Just a few thoughts on this. And these are just thoughts since,
after about 3 years of kayaking, I too consider myself a novice.

I appreciate your humility Dave. However, if there’s to be any
differentiation in our abilities/experience, as there should be, either I
have to change my description of my experience to something like “wouldn’t
recognize a sea kayak if it hit me in the butt,” or you have to change
yours to something like “novice-intermediate.” I’m hoping you’re willing
to change yours ;-). Perhaps I should change mine as well.

Also, I appreciate your thoughts on the skeg. I hadn’t thought of the
degree of deployment as a way to regulate the stern’s tendency to rotate to
down wind, relative to the bow’s tendency, and therefore regulate the
overall boat’s tendency toward stern-to-the-wind, bow-to-the-wind, or
neutral. Makes sense anyway.

--
Paul S.

"Paul Stivers" wrote in message
...
"Dave Van" wrote:

Just a few thoughts on this. And these are just thoughts since,
after about 3 years of kayaking, I too consider myself a novice.

I appreciate your humility Dave. However, if there's to be any
differentiation in our abilities/experience, as there should be, either I
have to change my description of my experience to something like "wouldn't
recognize a sea kayak if it hit me in the butt," or you have to change
yours to something like "novice-intermediate." I'm hoping you're willing
to change yours ;-). Perhaps I should change mine as well.


I think there's a lot to learn and always will be. I'm proud to be a novice
and so should you. It means we're not jaded.


Also, I appreciate your thoughts on the skeg. I hadn't thought of the
degree of deployment as a way to regulate the stern's tendency to rotate
to
down wind, relative to the bow's tendency, and therefore regulate the
overall boat's tendency toward stern-to-the-wind, bow-to-the-wind, or
neutral. Makes sense anyway.


I had the chance to paddle a Valley Aquila the other day in steady 15 to 20
MPH winds on a very choppy Lake Michigan. The skeg seemed to perform the
way I had anticipated. I think I may be a little light for the Aquila but
paddling with the wind with the skeg down, the kayak seemed "fairly"
cooperative in keeping on course. I think it would have done better for me
if it were loaded down a bit more. The owner of the boat was a little quiet
when I landed on the beach, forgetting to raise the skeg. That'll be
something I have to work on before I get a boat designed with a skeg.
Novices!

Have fun at the symposium. I wish I could afford the time to go.

DV

....stuff deleted
More rocker.

Adv. More responsive to leaning and paddle strokes.
Disadv. Less forgiving of unintentional variation in body position and
paddle stroke.
Disadv. More prone to weathercocking.

....more deleted

Weathercocking: The tendency for the boat to turn into the wind. While
this
is often referred to in the negative, it is not necessarily a
disadvantage.

Actually, it is. I have never, for any length of time, paddled solely into
the wind. Most conditions I've been in (up to 50 MPH winds, though generally
20 MPH or less), the wind and swell have not been perfectly aligned with
each other. Perhaps when one is out at sea and rebound waves (clapotis) are
less of a concern, this may be different. Generally, however, if you have
control of the boat, you are in a better situation than if the weather is in
control of the boat. For coastal kayaking, this means having the ability to
round a point and follow the coast rather than continue to paddle into a
headwind that will put you further out to sea to compensate for the poor
handling characteristics of the boat.

It seems to me that it would be nearly impossible to design a boat that is
not influenced by the wind in some way.

While this statement is true, having been in boats that have a very low
profile and which hug the water with such a passion that they are more
submarine than ship, I have to say that the wet ride is preferable to the
constant adjustments one must make for weather. As with any hull design,
this is a matter of trade-offs. No hull will completely windproof, but no
hull that has a high profile will be fun to paddle in difficult conditions.
Most boat designers offer a dryer ride, though many of the very long, very
narrow, British designs (VCP, Nordcapp) are designed to handle must more
difficult weather.

The choice, by design then, is to
design the boat so that it does tend to turn toward the wind. If your
intended course is into the wind, then this weathercocking would be an
advantage, would it not? This is where the skeg comes in. Contrary to
what
many believe, the skeg is not intended to increase tracking directly. It
does so indirectly by countering the boats tendency to weathercock.

....accurate statement on how skegs work deleted

Most designers add skegs and rudders because their boats are intended for
touring in moderate to calm conditions. Designs used by native tribesman had
no such design features and tended to be narrow, have hard chines, be 18+
feet long, and be very low in the water. Some had bifurcated hulls (which
seemed to keep the bow low in the water to avoid wind effects - as described
in the National Geo. presentation, "Baidarka"). None of these designs had
skegs because the hulls were designed for very harsh conditions and the skeg
would have added no performance advantage to the boat.


Upswept ends

Adv. Easier to roll. Boat is less stable upside down in the water.
Adv. Bow cuts through waves rather than punching through.
(Are there other advantages of an upswept stern? Cuts waves that
approach from the back?)
Disadv. Upswept stern is prone to weathercocking. Though a skeg can
largely mitigate this.

Well. That's the idea, I think.


The idea of the skeg? Yes. The upswept ends, however, do provide a bit of
windage to the hull. If you look closely at most of the "British designs,"
however, you will see that the upswept bow and stern is not pronounced when
viewed from in the water. The low volume of these boats means that the bow
and stern do not ride up the wave, but penetrate it (since there is a very
small air pocket in the bow, it provides very little lift). The waves flow
over the hull and those upswept ends (which seem higher than they are due to
the low deck height of the entire boat) are submerged and funciton much like
a skeg as it skewers the waves. This is a feature seen in many native
designs as well.

....stuff deleted

This is, by the way, how I understand things from what I've read and
experienced. I've only paddled a couple of these boats in fairly calm
conditions and for short periods of time. I am not kidding you about the low
volume and wet ride however. Fun, but dress for immersion as you will be wet
in these things.

Rick

Rick wrote:

Designs used by native tribesman had
no such design features and tended to be narrow, have hard chines, be 18+
feet long, and be very low in the water. Some had bifurcated hulls (which
seemed to keep the bow low in the water to avoid wind effects - as described
in the National Geo. presentation, "Baidarka"). None of these designs had
skegs because the hulls were designed for very harsh conditions and the skeg
would have added no performance advantage to the boat.

This is untrue. Skegs are actually very common on Greenlandic kayaks. They are
commonly either built into the hull by pulling the keel stringer into a hollow a
few feet forward of the stern, or of the strap on variety that is lashed to the
hull. I don't recall of seeing a skeg on a baidarka, but the Aleut may well have
used them, too.

--
Regards

Brian

Brian,

The greenlanders did, according to my references, use skegs on some designs.
I stand corrected. The references I've checked on baidarkas don't mention
same. Most of the Aleuts and greenlanders were sewn into their boats, which
meant landing on beaches where such devices would be easily damaged is left
deployed. I would assume that repairing/replacing these was a pretty common
occurance.

Rick

"Brian Nystrom" wrote in message
...


Rick wrote:

Designs used by native tribesman had
no such design features and tended to be narrow, have hard chines, be
18+
feet long, and be very low in the water. Some had bifurcated hulls
(which
seemed to keep the bow low in the water to avoid wind effects - as
described
in the National Geo. presentation, "Baidarka"). None of these designs
had
skegs because the hulls were designed for very harsh conditions and the
skeg
would have added no performance advantage to the boat.

This is untrue. Skegs are actually very common on Greenlandic kayaks. They
are
commonly either built into the hull by pulling the keel stringer into a
hollow a
few feet forward of the stern, or of the strap on variety that is lashed
to the
hull. I don't recall of seeing a skeg on a baidarka, but the Aleut may
well have
used them, too.

--
Regards

Brian