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From: Dave Kruger <kdruger_at_pacifier.com>
subject: [Paddlewise] Skin on Frame Boats
Date: Sat, 11 Sep 2004 09:36:58 -0700
Guy south of me a ways on the Oregon Coast.  Some nice photos of SOF boats: 
http://www.capefalconkayak.com/

He apparently paddles his in serious surf -- the beach there is very exposed.

No affiliation ... just something I found.

--
Dave Kruger
Astoria, OR 
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From: obrien <obrien_at_mail.albanyfirefighters.com>
subject: Re: [Paddlewise] Skin on Frame Boats
Date: Sun, 12 Sep 2004 17:02:53 -0700
That's Brian Shulz's web site.  I talked to him at the Depot Bay Wooden Boat festival last spring.  He had two nice s.o.f. boats as did his friend, Harvey Golden http://www.traditionalkayaks.com/index.html.  Harvey built a sailing s.o.f proa last year and was telling us how fun sailing it was, though he swam a lot.  Brian was finishing his sailing s.o.f. proa that was larger and probably more stable.  I have an interest in trying to sail a traction kite with a cobra wavewitch that has an under-hull rudder, but have been unable to find anyone kayak sailing with this type of kite.  So we talked about our different, yet similar paths of exploration.   Brian is a skilled W.W. paddler as well.  I haven't paddled with him yet, he paddles primarily solo and he's a bit far north.  Anyone interested in building a S.O.F. boat would do well to take one of his classes. 

My paddling partner, Doug Gordon, built a baidarka last year and we have done open coast trips with small craft advisory conditions and surf landings in 6ft. swell and smaller.  His baidarka handled very well including surf landings w/o pearling. It weighs about 30 lbs.  For other great photos of our coast, check out Jonathan Walpole's http://www.cs.pdx.edu/~walpole/kayaking.html.  Doug and I ran into Jonathan and his wife off Cascade Head.  We explored a cave that several Olympic size pools could fit within.  This was only the second time that I have run into other paddlers off our coast.  The other time was two guys in oc1's.  I paddle a surfski or a Seda Reveng SOT.  We seem to be a small eclectic group paddling an incredibly beautiful Coastline.   

---------- Original Message ----------------------------------
From: "Dave Kruger" <kdruger_at_pacifier.com>
Date:  Sat, 11 Sep 2004 09:36:58 -0700

>Guy south of me a ways on the Oregon Coast.  Some nice photos of SOF boats: 
>http://www.capefalconkayak.com/
>
>He apparently paddles his in serious surf -- the beach there is very exposed.
>
>No affiliation ... just something I found.
>
>--
>Dave Kruger
>Astoria, OR 
 




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From: Kirk Olsen <kork4_at_cluemail.com>
subject: Re: [Paddlewise] Skin on Frame Boats
Date: Sun, 12 Sep 2004 21:49:38 -0400
On Sat, 11 Sep 2004 09:36:58 -0700, "Dave Kruger" <kdruger_at_pacifier.com>
said:
> Guy south of me a ways on the Oregon Coast.  
> 
> He apparently paddles his in serious surf -- the beach there is very
> exposed.

Given my bias (I run the skin/frame kayak mailing list)

I think a skin on frame ends up stronger, in some ways than a 'glass
boat.  I did demos at a symposium with a friend and our standard
response to "it looks fragile" was to lift a 24 pound greenland style
boat to eye level and drop it onto the rock beach, where it bounced.

At a get together I saw a double kayak made with heavy nylon fabric
which was regularly beach landed, fully loaded, onto the barnicle/mussel
encrusted rocks on islands in Maine.  The skin looked pristine.


On a semi tangent, I just got back from the Arctic Kayaks weekend in
Mystic Connecticut.  At a rolling demo
one guy straightjacket rolled his feathercraft Kahuna.  So for those who
have questioned if a folder can be rolled, it turns out with some
considerable skill you don't even need to use your arms or a paddle to
roll one...  The person rolling the feathercraft was a gentleman from
Philadelphia named Dubside. 

Kirk  
-- 
  Kirk Olsen
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From: Nick Schade <nick_at_guillemot-kayaks.com>
subject: Re: [Paddlewise] Skin on Frame Boats
Date: Mon, 13 Sep 2004 13:50:24 -0400
Having dropped several of my strip-built kayaks from eye level and 
having them bounce I will say that it is not a great indication of 
strength for surfing and other real-world type forces. For one, if the 
SOF is lightly built it will be light in weight. Dropping a light 
weight object does not produce the same force as dropping a heavy 
object. Leaves are not considered that strong, but rarely break when 
falling from even very tall trees. The most you might be able to say is 
the boat is strong for its weight, but only if other boats tend to fail 
this test.

The loading of a kayak in surf is not the same as to load from dropping 
a kayak 6'. This is not to say that SOF boats are weak, or that they 
can't be used in surf, only that surviving a drop test is not all that 
relevant. A better test would be to put the boat across 2 saw horses 
and have someone hop up and down in the cockpit. At least then you 
testing with loads similar to those experienced in real use. The likely 
region of failure in most long sea kayaks would be in the cockpit area. 
I suspect SOF boats will have higher stress concentrations than 
monocoque boats because all the load will be concentrated in a few 
small parts: ribs, gunwales, deck beams.

Nick

On Sep 12, 2004, at 9:49 PM, Kirk Olsen wrote:

> On Sat, 11 Sep 2004 09:36:58 -0700, "Dave Kruger" 
> <kdruger_at_pacifier.com>
> said:
>> Guy south of me a ways on the Oregon Coast.
>>
>> He apparently paddles his in serious surf -- the beach there is very
>> exposed.
>
> Given my bias (I run the skin/frame kayak mailing list)
>
> I think a skin on frame ends up stronger, in some ways than a 'glass
> boat.  I did demos at a symposium with a friend and our standard
> response to "it looks fragile" was to lift a 24 pound greenland style
> boat to eye level and drop it onto the rock beach, where it bounced.
Nick Schade

Guillemot Kayaks
824 Thompson St
Glastonbury, CT 06033
USA
Ph/Fx: (860) 659-8847
http://www.guillemot-kayaks.com/
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From: Kirk Olsen <kork4_at_cluemail.com>
subject: Re: [Paddlewise] Skin on Frame Boats
Date: Mon, 13 Sep 2004 17:45:42 -0400
On Mon, 13 Sep 2004 13:50:24 -0400, "Nick Schade" <nick_at_guillemot-
kayaks.com> said:
> Having dropped several of my strip-built kayaks from eye level and
> having them bounce I will say that it is not a great indication of
> strength for surfing and other real-world type forces.


There you go with a perfectly good technical argument against a
potential consumer marketting ploy.

I would suggest modifying your proposed test to using a sling of some
form instead of the saw horse, so that the stress on the boat was
transfered from two single contact points to a distributed band on the
hull. I wouldn't want to use a flat sawhorse for a test on anything but
a
plastic boat.

Then you head into the disagreements like where to put the support
slings and how wide they are.  Testing your boats I want the support
bands to be 1/4 inch wide right at the ends, for my boats I'll take a 6
foot wide strap right under the paddler ;-)

I still believe skin/frame construction per se isn't an issue for surf
use.

I've happily played in New England surf in a skin/frame boat, and I do
realize most New England surf is not an impressive test.


It would be interesting to run a test as you propose between plastic,
skin/frame, fiberglass, plywood, and woodstrip boats having similar
shapes, and similar weights to see how they hold up.  But I'm not about
the fund that experiment....

Kirk
-- 
  Kirk Olsen
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From: Jim Farrelly <JFarrelly5_at_comcast.net>
subject: Re: [Paddlewise] Skin on Frame Boats
Date: Mon, 13 Sep 2004 18:04:44 -0400
Kirk Olsen wrote:

>
>
>It would be interesting to run a test as you propose between plastic,
>skin/frame, fiberglass, plywood, and woodstrip boats having similar
>shapes, and similar weights to see how they hold up.  But I'm not about
>the fund that experiment....
>
>Kirk
>  
>
Dont worry about funding Kirk.  Just donate your boats.  You can keep 
the ones that pass.

Jim et al
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From: Nick Schade <nick_at_guillemot-kayaks.com>
subject: Re: [Paddlewise] Skin on Frame Boats
Date: Mon, 13 Sep 2004 19:36:29 -0400
On Sep 13, 2004, at 5:45 PM, Kirk Olsen wrote:

> On Mon, 13 Sep 2004 13:50:24 -0400, "Nick Schade" <nick_at_guillemot-
> kayaks.com> said:
>> Having dropped several of my strip-built kayaks from eye level and
>> having them bounce I will say that it is not a great indication of
>> strength for surfing and other real-world type forces.
>
> I would suggest modifying your proposed test to using a sling of some
> form instead of the saw horse,...
>
> Then you head into the disagreements like where to put the support
> slings and how wide they are.  Testing your boats I want the support
> bands to be 1/4 inch wide right at the ends, for my boats I'll take a 6
> foot wide strap right under the paddler ;-)

I really don't think the hard point contact of the saw horse would be 
the failure point in most kayaks. I've often found myself stuck on one 
or two rocks with the water going away and just ended up with a bad 
scratch. I think for most boats the initial failure would be near the 
cockpit, not near the supports. Some boats might fail at the hatches. 
As you say, for the worst case scenario the support should be as far 
towards the ends of the boat as possible.
>
> I still believe skin/frame construction per se isn't an issue for surf
> use.

I agree, but for every strong kayak, there is a wave that is a little 
stronger. It is up to the paddler to stay on the safe side of that 
wave.

> It would be interesting to run a test as you propose between plastic,
> skin/frame, fiberglass, plywood, and woodstrip boats having similar
> shapes, and similar weights to see how they hold up.  But I'm not about
> the fund that experiment....

Yea, a good test should bring the sample to failure so you can compare 
the required load. While it would be a great time to perform the 
experiment, I would be seeking funding from outside sources.

Nick Schade

Guillemot Kayaks
824 Thompson St
Glastonbury, CT 06033
USA
Ph/Fx: (860) 659-8847
http://www.guillemot-kayaks.com/
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From: Gordin Warner <gwarner2_at_shaw.ca>
subject: Re: [Paddlewise] Skin on Frame Boats
Date: Mon, 13 Sep 2004 16:39:14 -0700
At 05:45 PM 13/09/2004 -0400, Kirk Olsen wrote:

>I would suggest modifying your proposed test to using a sling of some
>form instead of the saw horse, ....


I'd like to suggest using a sling shot.  The kayaks 
(SOF,SOT,Kevlar,Carbon,Wood, Fiberglass and any other material) could be 
fired from the sling shot out into the open ocean.  Fired first from the 
beach we could get an actual real speed for each boat thus laying to rest 
the arguments over which material and hull shape is the fastest.  Then we 
could fire them from say an elevation of 20 feet to simulate riding down a 
Tsunami into a dumping beach.

I'm sure further discussions could be resolved using this testing technique 
as well - such as which flies further a CRCA Level 4 kayaker, a BCU 4 Star 
or the equivalent ACA flier er I mean kayaker.

Your ever serious servant
Gordin
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From: <Niilus_at_aol.com>
subject: Re: [Paddlewise] Skin on Frame Boats
Date: Sun, 12 Sep 2004 22:26:02 EDT
In a message dated 9/12/2004 6:51:14 PM Pacific Daylight Time, 
kork4_at_cluemail.com writes:


> The person rolling the feathercraft was a gentleman from
> Philadelphia named Dubside. 
> 

Ralph Diaz has written about Dubside in the past in his newsletter.

Tony
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From: MICHAEL SILVIUS <M.Silvius_at_worldnet.att.net>
subject: Re: [Paddlewise] Skin on Frame Boats
Date: Mon, 13 Sep 2004 12:19:00 -0400
Kirk:

I am not sure if you caught it but Dubside actually went to Greenland this
yr and came out with a number of medals. Only second to Maligiaq in the men'
s category. Of course he was in the "foreigner" (non Greenlandic boat)
category. He is the only one known to fully complete a straight jacket roll
without lifting his elbows. Others do it, but fail to qualify for full
points as they inevitably lift their elbows away from the torso.

And he does it all in that tub!!!!!  must be all the beansprouts and toffu
he eats!!!!

if you did not catch it his ropes demo is increddible.

Michael.

----- Original Message ----- 
From: "Kirk Olsen" <kork4_at_cluemail.com>
> On a semi tangent, I just got back from the Arctic Kayaks weekend in
> Mystic Connecticut.  At a rolling demo
> one guy straightjacket rolled his feathercraft Kahuna.  So for those who
> have questioned if a folder can be rolled, it turns out with some
> considerable skill you don't even need to use your arms or a paddle to
> roll one...  The person rolling the feathercraft was a gentleman from
> Philadelphia named Dubside.
>
> Kirk
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From: Kirk Olsen <kork4_at_cluemail.com>
subject: Re: [Paddlewise] Skin on Frame Boats
Date: Mon, 13 Sep 2004 12:49:38 -0400
On Mon, 13 Sep 2004 12:19:00 -0400, "MICHAEL SILVIUS"
<M.Silvius_at_worldnet.att.net> said:

> I am not sure if you caught it but Dubside actually went to Greenland
> this yr and came out with a number of medals. Only second to Maligiaq in the
> men's category. Of course he was in the "foreigner" (non Greenlandic boat)
> category. He is the only one known to fully complete a straight jacket
> roll without lifting his elbows. Others do it, but fail to qualify for full
> points as they inevitably lift their elbows away from the torso.

I also liked his "roll with you hands in your lap".  A nice
_comfortable_ looking
roll.  As to how he does it, I haven't a clue.

> if you did not catch it his ropes demo is incredible.

I did see the rope gymnastic demo.  I was even foolish enough to think I
had figured
out how to do one move that Dubside hadn't figured out how to do. 
WRONG...  I'm tempted
to put some ropes at home.

Greg Stamer has an article on rope gymnastics and a some video clips for
those
who are interested:

http://www.qajaqusa.org/Technique/ropegymnastics.htm

Kirk
-- 
  Kirk Olsen
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From: Shawn Baker <shawnkayak_at_yahoo.com>
subject: Re: [Paddlewise] Skin on Frame Boats
Date: Fri, 17 Sep 2004 07:02:10 -0700 (PDT)
Nick Schade wrote:
>Yea, a good test should bring the sample to failure so you can compare

the required load. While it would be a great time to perform the 
experiment, I would be seeking funding from outside sources.

Come on, Nick, I'll put one of my boats against one of your boats; a
$1,000 wager.  My wife is a CPA, and she'll hold the money.  We'll take
our kayaks on a whitewater expedition, we'll each paddle our own kayaks
halfway.  Then, we'll paddle each other's kayaks the other half.  The
winner takes the money and both boats home.

;)

Shawn


		
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From: Matt Broze <mkayaks_at_oz.net>
subject: Re: [Paddlewise] Skin on Frame Boats
Date: Wed, 22 Sep 2004 18:53:56 -0700
Rob G wrote:

>>>>>Could I replicate an outstanding SOF
design in glass and make it perform as well?<<<<<

Not likely. Corry Freedman (Spirit Line Kayaks) made a glass mold from a
very nice handling Aleut replica kayak he had made. The resulting glass
kayak was not a real nice kayak. One of its problems was that it gave a much
wetter ride that the same shaped SOF had been. I analyzed the problem to be
the lack of longitudinal flex in the fiberglass kayak compared to the SOF.
While the bow volume had been plenty when the bow could bend to lift over
the waves that same volume was totally inadequate when it couldn't flex
nearly as much.

Matt Broze
www.marinerkayaks.com
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From: alex <al.m_at_3web.net>
subject: Re: [Paddlewise] Skin on Frame Boats
Date: Wed, 22 Sep 2004 19:08:13 -0700
> very nice handling Aleut replica kayak he had made. The resulting glass
> kayak was not a real nice kayak. One of its problems was that it gave a
much
> wetter ride that the same shaped SOF had been. I analyzed the problem to
be
> the lack of longitudinal flex in the fiberglass kayak compared to the SOF.
> While the bow volume had been plenty when the bow could bend to lift over
> the waves that same volume was totally inadequate when it couldn't flex
> nearly as much.

Didn't want to interfere when Titans were figting ;-),  just wonder if
*performance* should normally mean comfort or mechanical strength in rough
conditions, and not speed, (when flex and inherent bumps and dents of SOF
hull might become a hindrance).
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From: Kirk Olsen <kork4_at_cluemail.com>
subject: Re: [Paddlewise] Skin on Frame Boats
Date: Thu, 23 Sep 2004 09:45:47 -0400
On Wed, 22 Sep 2004 19:08:13 -0700, "alex" <al.m_at_3web.net> said:
> > very nice handling Aleut replica kayak he had made. The resulting glass
> > kayak was not a real nice kayak. <snip>
> > While the bow volume had been plenty when the bow could bend to lift over
> > the waves that same volume was totally inadequate when it couldn't flex
> > nearly as much.
> 
> just wonder if
> *performance* should normally mean comfort or mechanical strength in
> rough
> conditions, and not speed, (when flex and inherent bumps and dents of SOF
> hull might become a hindrance).

Are you sure that the flex of a SOF is a hinderance in rough conditions?

For a "well built" SOF the dents are between the stringers and should
not impede
the flow of water when the kayak is underway.  
-- 
  Kirk Olsen
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From: Gordin Warner <gwarner2_at_shaw.ca>
subject: Re: [Paddlewise] Skin on Frame Boats
Date: Thu, 23 Sep 2004 08:36:28 -0700
At 09:45 AM 23/09/2004 -0400, Kirk Olsen wrote:
> > conditions, and not speed, (when flex and inherent bumps and dents of SOF
> > hull might become a hindrance).
>
>Are you sure that the flex of a SOF is a hinderance in rough conditions?
>
>For a "well built" SOF the dents are between the stringers and should
>not impede
>the flow of water when the kayak is underway.
"dents" or dimples built into them.  I'm sure I'm using the wrong word 
here. The theory, as I understand it, is similar to the dimples on a golf 
ball.  The indentations purpose is to break the solid plane of water that 
flows continuously over a smooth hull surface.  This plane of water creates 
friction.  Bust up the plane and there's less friction.

The same thing occurs on float planes.  Ask any pilot and they'll tell you 
it takes less power to take off of choppy water then smooth flat calm water 
as there is less drag on the pontoons.

If the theory is correct a SOF kayak should enjoy a positive gain from the 
indentations along the hull.  I suppose the size of the indentations might 
have a negative affect on this.  Now as for the flexing I'll leave that to 
more knowledgeable kayakers.

As an aside I'm faced with an interesting choice to make.  This fall/winter 
I want to start in on building another boat.  This will be boat number 
three.  My choices are, a skin on frame, a surf boat or a rowing sailing 
dingy. Maybe I could combine the two and design and build a SOF surf boat. 
;-)  The dingy will have to wait.
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From: Michael Daly <mikedaly_at_magma.ca>
subject: Re: [Paddlewise] Skin on Frame Boats
Date: Thu, 23 Sep 2004 13:45:55 -0400
On 23 Sep 2004 at 8:36, Gordin Warner wrote:

> If the theory is correct a SOF kayak should enjoy a positive gain from
> the indentations along the hull.  I suppose the size of the
> indentations might have a negative affect on this.

The size is critical.  It is also related to the velocity of the 
fluid along the surface.  Golf balls have small dimples and move 
quite fast.  SOF kayaks have relatively smooth changes over a large 
scale and move slowly in the water.

I doubt that the shape changes in the SOF have a significant effect 
on the flow.

BTW, aircraft floats operate by planing, not displacement (well, as 
you get anywhere near take off speed), so I doubt the analogy is 
completely correct.

Mike
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From: Nick Schade <nick_at_guillemot-kayaks.com>
subject: Re: [Paddlewise] Skin on Frame Boats
Date: Thu, 23 Sep 2004 17:10:21 -0400
On Sep 23, 2004, at 11:36 AM, Gordin Warner wrote:
> "dents" or dimples built into them.  I'm sure I'm using the wrong word 
> here. The theory, as I understand it, is similar to the dimples on a 
> golf ball.  The indentations purpose is to break the solid plane of 
> water that flows continuously over a smooth hull surface.  This plane 
> of water creates friction.  Bust up the plane and there's less 
> friction.

Like many theories dent = dimples sounds good. But a kayak isn't a golf 
ball and the dents and dimples only have a superficial resemblance. 
This kind of theory is of the look-alike-work-alike class. Greenland 
paddles look like an efficient glider wing, therefore must be more 
efficient; SOF kayak dents look like golf-ball dimples; horseradish 
looks like male genitalia therefore it must be an aphrodisiac. 
Sometimes resemblance is just coincidental.

For something to work the same, it must actually work the same. 
Horseradish is not genitalia and kayaks don't fly spinning through the 
air. This is not to say the SOF dents don't do good things, it is just 
that what ever they do has nothing to do with golf balls dimples.

Nick Schade

Guillemot Kayaks
824 Thompson St
Glastonbury, CT 06033
USA
Ph/Fx: (860) 659-8847
http://www.guillemot-kayaks.com/
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From: Gordin Warner <gwarner2_at_shaw.ca>
subject: Re: [Paddlewise] Skin on Frame Boats
Date: Thu, 23 Sep 2004 16:57:56 -0700
At 05:10 PM 23/09/2004 -0400, Nick Schade wrote:

>Like many theories dent = dimples sounds good. But a kayak isn't a golf 
>ball and the dents and dimples only have a superficial resemblance. This 
>kind of theory is of the look-alike-work-alike class. Greenland paddles 
>look like an efficient glider wing, therefore must be more efficient; SOF 
>kayak dents look like golf-ball dimples; horseradish looks like male 
>genitalia therefore it must be an aphrodisiac. Sometimes resemblance is 
>just coincidental.
Perhaps someone out there could test the theory by taking a ball bean 
hammer to the outside of their hard shell kayak. ;-)

I hope this does not evolve into one of those endless strings.  I'm not 
even a proponent of the theory. I was just reflecting on what I'd 
heard/read. So if this dies I won't be disappointed.

However, the next time I have roast beef and a horseradish garnish I will 
pay more attention to the after affects.

Gordin
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