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From: Dave Kruger <dkruger_at_pacifier.com>
subject: [Paddlewise] Reinforcing Flimsy Back Deck
Date: Sun, 20 Feb 2000 19:39:23 -0800
I have a vintage 1993 Eddyline Wind Dancer, which has a too-light layup on the
back deck, aft of the rear hatch.  It's strong enough, but just not rigid
enough.  When I slide my upper torso across it preparatory to re-entering the
cockpit (in a paddlefloat self-rescue), it flexes a lot.  It has flexed so
badly, there are a couple loooong gel coat cracks.

I'm not concerned about the ugliness of the gel coat cracks, but with the
effects of repeated flexes of the back deck.  I suspect it will fail one of
these days.  So, I have begun to reinforce it with epoxy/glass layers.

I laid in a sizeable reinforcement patch of 6 oz cloth, but that does not seem
to be enough.  I'm getting ready to apply another layer of 6 oz cloth.

Anybody got experience with this sort of repair/reinforcement?  My yakking
buddy just acquired a vintage 1994 Wind Dancer, which shows the same problem --
and we intend to fix it, also, so any advice will be doubly useful!

Thanks,

-- 
Dave Kruger
Astoria, OR
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From: <JCMARTIN43_at_aol.com>
subject: Re: [Paddlewise] Reinforcing Flimsy Back Deck
Date: Sun, 20 Feb 2000 23:27:10 EST
Dave wrote, " I have a vintage 1993 Eddyline Wind Dancer, which has a too-light layup on the back deck, aft of the rear hatch.  It's strong enough, but just not rigid enough."

Am having trouble trying to imagine how you're getting aft of the aft hatch in a paddlefloat recovery, but one thing that worked for me on my Pintail when I started developing stress cracks aft of the after bulkhead was to add a second bulkhead of two inch closed cell foam about 12 inches further aft, just forward of the aft hatch.  It stabilized the deck enough to keep it from cracking further --- getting in and out of a Pintail requires sitting on the after deck and sliding in straight-kneed --- and seems to have done the job without introducing alternative sources of stress.  Might be something to think about; too many more layers of six ounce glass and the resin to hold it together on the back deck and you'll have a squirt sea kayak!  Or a permanent endo boat, anyway.
 
Jack Martin

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From: ralph diaz <rdiaz_at_ix.netcom.com>
subject: Re: [Paddlewise] Reinforcing Flimsy Back Deck
Date: Mon, 21 Feb 2000 08:41:41 -0800
Dave Kruger wrote:
> 
> I have a vintage 1993 Eddyline Wind Dancer, which has a too-light layup on the
> back deck, aft of the rear hatch.  It's strong enough, but just not rigid
> enough.  When I slide my upper torso across it preparatory to re-entering the
> cockpit (in a paddlefloat self-rescue), it flexes a lot.  It has flexed so
> badly, there are a couple loooong gel coat cracks.
> 
> I'm not concerned about the ugliness of the gel coat cracks, but with the
> effects of repeated flexes of the back deck.  I suspect it will fail one of
> these days.  So, I have begun to reinforce it with epoxy/glass layers.


Just thinking out loud.  I seem to recall your commenting that you are a
hefty size and weight.  I wonder if what you should be doing instead of
creating greater layers of kayak skins, you might want to put some
reinforcement pillars inside the rear compartment.  This would be
similar to what whitewater kayaks have to prevent the paddler from being
pinned in his boat if the boat gets crushed against a strainer or rock. 
It usually is in the form of a center pillar running part of the length
of the boat (in the WW case, in the bow where the paddler's legs go). 
This might sacrifice some storage room in the stern compartment but you
could devise a pattern of pillaring that would reduce the amount of
space you would lose.

Again, just thinking out loud.

ralph diaz

-- 
-----------------------------------------------------------------------
Ralph Diaz . . . Folding Kayaker newsletter
PO Box 0754, New York, NY 10024
Tel: 212-724-5069; E-mail: rdiaz_at_ix.netcom.com
"Where's your sea kayak?"----"It's in the bag."
-----------------------------------------------------------------------
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From: Erik Sprenne <sprenne_at_netnitco.net>
subject: Re: [Paddlewise] Reinforcing Flimsy Back Deck
Date: Mon, 21 Feb 2000 08:27:51 -0600
Dave wrote:
> I have a vintage 1993 Eddyline Wind Dancer, which has a too-light layup
on the
> back deck, aft of the rear hatch.  It's strong enough, but just not rigid
> enough.  
> <snip>
> I suspect it will fail one of
> these days.  So, I have begun to reinforce it with epoxy/glass layers.
> 
> I laid in a sizeable reinforcement patch of 6 oz cloth, but that does not
seem
> to be enough.  <snip>
> 

Strength and rigidity are not necessarily the same thing with fiberglass,
even though Doug Lloyd has his personal preferences for a very stiff  boat.

It's very hard to make specific recommendations without seeing the boat, or
knowing exactly what you want out of the reinforcement, but here are a
couple of things to consider.

A single layer of 6 oz cloth will provide some additional strength, but not
much rigidity.  Better to use 2 or 3 layers of 6 oz cloth - applied at the
same time - which will give the most added strength for the least weight
and added thickness.  The multiple layers of the glass cloth will 'nest'
together better if they are all applied at the same time.  An additional
benefit of using multiple layers applied together is that you have a much
better chance of avoiding pinholes as compared to adding only a single
layer reinforcement.  

A simple experiment - cut out small test swatches of 6 oz cloth, setting up
1, 2, and 3 layer test pieces of the same dimensions (do this on a
polyethylene bag, as the cured epoxy will peel off PE).  Wet them out with
epoxy, using a minimum amount.  After the epoxy cures, compare the
stiffness of the test pieces against the number of layers.  You may be
amazed at how flexible a single layer of fiberglass is :-)  Another
interesting comparison would be to then add a second layer test swatch to
the already-cured single layer, and compare its stiffness - and weight - to
the two-layer-at-once test piece.

If you really want rigidity, you may want to consider using woven roving
(forget if it is 24 or 27 oz. cloth) for the reinforcement.  It will result
in greater stiffness, but not a very water-tight reinforcement (the glass
fibers are very large, but not tightly-woven).  It's also more difficult to
work with in general, especially to coax it to lay flat if there are any
creases in the heavy cloth (e.g. - if it has been stored folded).

With any reinforcement to the inside of the deck, it would be best to have
the reinforcement piece cover the entire deck side-to-side (all the way to
the side seams) to prevent the formation of stress risers at the edges of
the reinforcement(s) that would concentrate flexing stresses there.  

regards,
Erik Sprenne
at the southern end of Lake Michigan (where it's supposed to get into the
50's this week!)

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From: Dave Kruger <dkruger_at_pacifier.com>
subject: Re: [Paddlewise] Reinforcing Flimsy Back Deck
Date: Mon, 21 Feb 2000 07:43:47 -0800
Erik Sprenne wrote:
> 
> Dave wrote:
> > I have a vintage 1993 Eddyline Wind Dancer, which has a too-light layup
> >on the back deck, aft of the rear hatch.  It's strong enough, but just not
> > rigid enough. [snip] 

> A single layer of 6 oz cloth will provide some additional strength, but not
> much rigidity.  Better to use 2 or 3 layers of 6 oz cloth - applied at the
> same time - which will give the most added strength for the least weight
> and added thickness.  The multiple layers of the glass cloth will 'nest'
> together better if they are all applied at the same time.  An additional
> benefit of using multiple layers applied together is that you have a much
> better chance of avoiding pinholes as compared to adding only a single
> layer reinforcement. [snip]

> If you really want rigidity, you may want to consider using woven roving
> (forget if it is 24 or 27 oz. cloth) for the reinforcement.  It will result
> in greater stiffness, but not a very water-tight reinforcement (the glass
> fibers are very large, but not tightly-woven).  [snip]

Thanks to Erik and the others who responded.  I am off to apply the suggestions
-- naturally all this is being done *inside* the rear hatch, in tight
quarters.  Two more layers of 6 oz cloth ought to do it, I think, laid "the
Erik way."

-- 
Dave Kruger
Astoria, OR
avoiding pillars to retain my storage
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From: <JSpinner_at_aol.com>
subject: Re: [Paddlewise] Reinforcing Flimsy Back Deck
Date: Mon, 21 Feb 2000 18:21:38 EST
In a message dated 2/21/00 8:50:10 AM, rdiaz_at_ix.netcom.com writes:

<< Just thinking out loud.  I seem to recall your commenting that you are a
hefty size and weight.  I wonder if what you should be doing instead of
creating greater layers of kayak skins, you might want to put some
reinforcement pillars inside the rear compartment.  This would be
similar to what whitewater kayaks have to prevent the paddler from being
pinned in his boat if the boat gets crushed against a strainer or rock. 
It usually is in the form of a center pillar running part of the length
of the boat (in the WW case, in the bow where the paddler's legs go). 
This might sacrifice some storage room in the stern compartment but you
could devise a pattern of pillaring that would reduce the amount of
space you would lose >>


In a message dated 2/21/00 8:50:10 AM, rdiaz_at_ix.netcom.com writes:

<< Just thinking out loud.  I seem to recall your commenting that you are a
hefty size and weight.  I wonder if what you should be doing instead of
creating greater layers of kayak skins, you might want to put some
reinforcement pillars inside the rear compartment.  This would be
similar to what whitewater kayaks have to prevent the paddler from being
pinned in his boat if the boat gets crushed against a strainer or rock. 
It usually is in the form of a center pillar running part of the length
of the boat (in the WW case, in the bow where the paddler's legs go). 
This might sacrifice some storage room in the stern compartment but you
could devise a pattern of pillaring that would reduce the amount of
space you would lose >>

In my new CD Gulfstream that is how they support the coaming area. The cheek 
straps, or whatever you call those things, go from the edge of the cockpit to 
the bottom of the boat on both sides. They create a great storage space for 
sponges and water bottles, if you can shove your arm between yourself and the 
coaming. I have to admit that with the extra paddling I carry those things 
make me feel easier about sitting up on the back of the cockpit  with the in 
and out process, even with a paddle assist.

Joan Spinner
   * * *
Happily paddling on a thawed Chesapeake Bay 
watershed. The Gulfie had her maiden
voyage today and was worth all the
aggravation with the seat. NICE boat!
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From: Nick Von Robison <n.v.rob_at_deltanet.com>
subject: Re: [Paddlewise] Reinforcing Flimsy Back Deck
Date: Mon, 21 Feb 2000 13:29:49 -0800
> > > I have a vintage 1993 Eddyline Wind Dancer, which has a too-light layup
> > >on the back deck, aft of the rear hatch.  It's strong enough, but just not
> > > rigid enough. [snip]
>

Dave, first take a look at Ferenc Mates' book "From a Bare Hull" (1983 Albatross
pubs.) where he gets into strengthening fiberglass decks in yachts in some detail.
He uses closed cell ureathane foam shaped like a squared or trapazoid (?) beam,
contact glued to the underside, then a couple layers of cloth laid up over it and
tapered.  The foam obviously doesn't give any stiffness or rigidity (maybe some
flotation?) but it's the shape of the "beam" that does the stiffening.  Those beams
probably wouldn't have to be any more than 1.5" x 3.4" so you wouldn't be losing
much room in the bulkhead.

Think about the top of a wooden acoustic guitar.  Those tops are about 7/64" thick
and even if you tripled the thickness, you'd still not get the ridigity of thin the
fan bracing inside
the guitar.  My$.02.

-Nick




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