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Date: 27 Jul 2004 06:48:59
From: Jeff Potter
Subject: Repair hogging in kevlar hull?
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I know of an old kevlar racing canoe that's been stored upsidedown on
sawhorses for a decade. It has sagged and now it has a lot of reverse
rocker. Bummer. Can this be corrected? What about storing it right
side up with logs in the center? --JP
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Date: 29 Jul 2004 15:19:35
From: Eric Nyre
Subject: Re: Repair hogging in kevlar hull?
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While more apparent in the older boats, this is a problem for all
composite boats.
Fiberglass and similar composites are actually Fiber Reinforced
Plastic FRP. The resins which the fabrics are saturated with are
various types of plastic, with Polyester, Vinylester and Epoxy being
the most common.
These plastics will deform over time, assuming the most natural/
relaxed position. Over the years your upside down boat just gradually
slumped. On boats with reinforcing ribs, the ribs tend to become more
apparent over time due to the same effect.
The suggestions for storing the boat in a sling, putting some weight,
etc are all good. If you put the boat where it will get warm, the
effect should be faster because the plastics do soften in the heat.
120 degrees will tweak almost any hull in a few days (a boat left in
the sun on a 90 degree day will get over 120 degrees). Sand will
absorb and hold the heat well, as does water (water is tricky though,
the boat has to be lined up right for it to work).
You may also just make the thwarts a little wider. Pushing out the
thwarts will splay the boat, lifting the ends, thus giving the boat
some rocker. Making the thwarts wider won't make it illegal for racing
as long as it meets specs (it will probably exceed them being wider
than before).
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Date: 27 Jul 2004 22:45:57
From: Dan Valleskey
Subject: Re: Repair hogging in kevlar hull?
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Hi Jeff-
Paddle it anyway. It won't be race legal, but I bet it works okay as
a work-out boat.
-Dan V.
On 27 Jul 2004 06:48:59 -0700, JeffOYB@hotmail.com (Jeff Potter)
wrote:
>I know of an old kevlar racing canoe that's been stored upsidedown on
>sawhorses for a decade. It has sagged and now it has a lot of reverse
>rocker. Bummer. Can this be corrected? What about storing it right
>side up with logs in the center? --JP
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Date: 28 Jul 2004 07:02:20
From: Jeff Potter
Subject: Re: Repair hogging in kevlar hull?
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Dan Valleskey <valleskey at comcast dot net > wrote in message news:<1a8eg0pq1s8scmaerppdof5ai0aj0o0ihp@4ax.com>...
> Hi Jeff-
> Paddle it anyway. It won't be race legal, but I bet it works okay as
> a work-out boat.
A hogged boat isn't legal? Weird.
I wanted it for use on a twisty river with casual paddlers
(wife'n'kids). The hog would seem to make for TOUGH cornering. The
current owner says to just roll it on side and ends come out and a
turn is easy, but...
Speaking of legal... Is a rudder legal in a flatwater hut-boat race?
(MCRA?) What about using a pole instead of / in addition to a paddle?
--JP
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Date: 28 Jul 2004 22:39:12
From: Fred Klingener
Subject: Re: Repair hogging in kevlar hull?
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"Jeff Potter" <JeffOYB@hotmail.com > wrote in message
news:46b1eeb4.0407280602.32916ab4@posting.google.com...
> Dan Valleskey <valleskey at comcast dot net> wrote in message
news:<1a8eg0pq1s8scmaerppdof5ai0aj0o0ihp@4ax.com >...
> > Hi Jeff-
> > Paddle it anyway. It won't be race legal, but I bet it works okay as
> > a work-out boat.
>
> A hogged boat isn't legal? Weird.
>
> I wanted it for use on a twisty river with casual paddlers
> (wife'n'kids). The hog would seem to make for TOUGH cornering. The
> current owner says to just roll it on side and ends come out and a
> turn is easy, but...
The 'negative rocker' might be the most apparent property of hogging, but
functionally it mainly decreases primary stability - not a great thing for
novices and kids.
I'd hang it in the sun from its thwarts/gunnels and fill it with sand or
water. Historically, paying rerspect to the boat spirits with dancing,
drumming, and singing seem to have been effective.
You might try carving some ribs and jamming them in to see whether they
help. (See any video on bark boat building. ;)
Hth,
Fred Klingener
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Date: 28 Jul 2004 20:50:26
From: Marsh Jones
Subject: Re: Repair hogging in kevlar hull?
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Jeff Potter wrote:
> Dan Valleskey <valleskey at comcast dot net> wrote in message news:<1a8eg0pq1s8scmaerppdof5ai0aj0o0ihp@4ax.com>...
>
>>Hi Jeff-
>>Paddle it anyway. It won't be race legal, but I bet it works okay as
>>a work-out boat.
>
>
> A hogged boat isn't legal? Weird.
>
> I wanted it for use on a twisty river with casual paddlers
> (wife'n'kids). The hog would seem to make for TOUGH cornering. The
> current owner says to just roll it on side and ends come out and a
> turn is easy, but...
>
> Speaking of legal... Is a rudder legal in a flatwater hut-boat race?
> (MCRA?) What about using a pole instead of / in addition to a paddle?
>
> --JP
Nope:
Rule V.A.9 Rudders: There shall be no mechanical steering devices in any
USCA classes except the ICF Kayak class. This does not include fixed
keel or skegs as deemed allowable under present keel and concavity rules.
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Date: 28 Jul 2004 20:47:16
From: Marsh Jones
Subject: Re: Repair hogging in kevlar hull?
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Jeff Potter wrote:
> Dan Valleskey <valleskey at comcast dot net> wrote in message news:<1a8eg0pq1s8scmaerppdof5ai0aj0o0ihp@4ax.com>...
>
>>Hi Jeff-
>>Paddle it anyway. It won't be race legal, but I bet it works okay as
>>a work-out boat.
>
>
> A hogged boat isn't legal? Weird.
>
> I wanted it for use on a twisty river with casual paddlers
> (wife'n'kids). The hog would seem to make for TOUGH cornering. The
> current owner says to just roll it on side and ends come out and a
> turn is easy, but...
>
> Speaking of legal... Is a rudder legal in a flatwater hut-boat race?
> (MCRA?) What about using a pole instead of / in addition to a paddle?
>
> --JP
Jeff,
Various people have used additional vertical bracing to push the bottom
down and back into the original lines. Try this. Tack (hotglue to
start with) a longitudinal stringer down the inside keelline - maybe a
foot longer than the distance between the center thwarts. Cut vertical
braces slightly longer than the gap between this stringer and the
thwarts above. Cup the top end to keep it from slipping off the thwart,
and wedge into place. Check the bottom. If that takes out most of the
hog, great. Work on storing the boat in an upright position - maybe on
slings?
Marsh
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Date: 28 Jul 2004 22:03:37
From: Michael Daly
Subject: Re: Repair hogging in kevlar hull?
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On 28-Jul-2004, Marsh Jones <marshjones@comcast.net > wrote:
> foot longer than the distance between the center thwarts. Cut vertical
> braces slightly longer than the gap between this stringer and the
> thwarts above. Cup the top end to keep it from slipping off the thwart,
> and wedge into place. Check the bottom. If that takes out most of the
> hog, great.
This sounds like it will take out beamwise hogging. I was under the
impression he has lengthwise hogging.
Jeff, which is it?
Mike
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Date: 29 Jul 2004 06:47:19
From: Jeff Potter
Subject: Re: Repair hogging in kevlar hull?
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"Michael Daly" <michaelDaly@foo.bar > wrote in message news:<koqdnRfXAe0Mv5XcRVn-pg@magma.ca>...
> On 28-Jul-2004, Marsh Jones <marshjones@comcast.net> wrote:
>
> > foot longer than the distance between the center thwarts. Cut vertical
> > braces slightly longer than the gap between this stringer and the
> > thwarts above. Cup the top end to keep it from slipping off the thwart,
> > and wedge into place. Check the bottom. If that takes out most of the
> > hog, great.
>
> This sounds like it will take out beamwise hogging. I was under the
> impression he has lengthwise hogging.
>
> Jeff, which is it?
I think they're related. The center area sagged so the ends lost their
rocker. It was stored on sawhorses for years. In sun. Weighting and
boosting the center thwart and dancing all sound like good ideas.
--JP
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Date: 27 Jul 2004 19:00:22
From: Michael Daly
Subject: Re: Repair hogging in kevlar hull?
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On 27-Jul-2004, JeffOYB@hotmail.com (Jeff Potter) wrote:
> I know of an old kevlar racing canoe that's been stored upsidedown on
> sawhorses for a decade. It has sagged and now it has a lot of reverse
> rocker. Bummer. Can this be corrected? What about storing it right
> side up with logs in the center? --JP
I seem to remember some folks complaining in the old days about creep
in Kevlar. I haven't heard much about it lately.
I'd guess that the process is reversible. But don't put logs in it.
I'd try something like sand spread out evenly over the whole inside.
Don't forget that its own weight caused it to bend; if you weigh it
down with some other weight distribution, it will bend back according
to _that_ load. Expect it to take quite a while.
Mike
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Date: 27 Jul 2004 16:50:16
From: Rick
Subject: Re: Repair hogging in kevlar hull?
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Jeff Potter wrote:
> I know of an old kevlar racing canoe that's been stored upsidedown on
> sawhorses for a decade. It has sagged and now it has a lot of reverse
> rocker. Bummer. Can this be corrected? What about storing it right
> side up with logs in the center? --JP
Hogging (the process where the water bouys up the beamy center of a
boat, but not the ends) is hard to defeat (and is the shape you describe
here). I don't know how kevlar might respond to attempts to reverse the
effect, but the hull is not likely to ever resume its natural shape even
if bending it back is somewhat successful.
On a historical note, the USS Constitution had been floating since its
launch in the early 1800's and developed a significant hog to its hull.
During the refit done in the 80's or 90's, I forget which, most of the
old lumber had to be replaced to counter this effect. There was an
article on how they repaired this for its sail up and down the east
coast in National Geographic a while back.
Rick
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