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Catalina 25 Specific Forum

Kevlar reinforced swing keel trunk

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albert
Captain

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USA
262 Posts

Initially Posted - 03/22/2002 : 02:18:44

Does anyone have experience working with kevlar cloth?

I've seen it sold by the yard and it was reasonably priced. Wouldn't it be better to add a couple of layers of kevlar around the keel trunk head instead of fiberglass cloth? The assumption is that since the keel trunk head is a known point of weakness in the swingkeelers, why not really strengthen the trunk with a couple of layers of kevlar cloth?

Issues:
--How is kevlar applied?
--Will it "flex" enough to follow the contour of the keel trunk?
--Is it worth the trouble? ie. would a couple of layers of kevlar around the aft of the keel trunk head be able to withstand a full keel drop without cracking open?

Albert Iturrey
al@comhertz.com
Abacus': http://www.comhertz.com/abacus

Edited by - on

OJ
Master Marine Consultant

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USA
4382 Posts

Response Posted - 03/22/2002 : 11:40:05

I think your 3rd point is more on track. Even with a couple layers of Kevlar (even if it's compatible with fibreglass) I think there would still be considerable damage to the trunk if the keel cable would fail in the retracted position. To me, vigilant maintenance and keeping the keel from grounding would be easier and more effective in the long run. I used the latter arguement to justify my new digtal depth meter to my first mate! <img src=icon_smile_wink.gif border=0 align=middle>

Steve Madsen
#2428
OJ(Ode to Joy)

[url="http://catalina25-250.org/photo0.htm/"]<img src="http://www.catalina25-250.org/photo/ode075.jpg" border=0>[/url]

Edited by - OJ on 03/22/2002 11:46:52

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Champipple
Master Marine Consultant

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USA
6855 Posts

Response Posted - 03/22/2002 : 22:25:01

I agree with Steve, regular maintenance and inspection is the way to go. When our boat was purchased 5 years ago it had the original cable. I can't say much for the first owners methods, but this cable really do hold up for a long time its a 1978. We just changed it last year (thanks in part to this site) and it still probably could have gone even longer.

My point is, if the keel drops your really SOL It has happened to both new and old cables. But, out of all the swings made, its a rare occurence.

Take a look at the cable monthly; Inspect while out of the water annually; leave it down as often as possible and last but not least, pray a little. if your an atheist, wish or an agnostic, choose one and pray.

Although Steve seems to thing your third point is more on track, does anyone want to test it to find out????
And Lastly....
<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>
I used the latter arguement to justify my new digtal depth meter to my first mate!
<hr height=1 noshade id=quote></BLOCKQUOTE id=quote>

Who you kiddin Steve, you know shes the Admiral!!! and your the first mate!!

DW

Duane Wolff
"The Flying Wasp"
C-25, #401 std,sk
Chief Measurer C-25/250 national Org.
<img src="http://im1.shutterfly.com/procserv/47b2dc20b3127cce9cd2f45b211a0000004010" border=0>

Edited by - Duane Wolff on 03/22/2002 22:26:58

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dlucier
Master Marine Consultant

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Virgin Islands (United Kingdom)
7583 Posts

Response Posted - 03/22/2002 : 23:35:54

Just found this today at the CatalinaOwners forum:

Lost Swing Keel?
Submitted by Michael of Port St. Lucie on 03/22 at 03:32PM regarding Catalina 22.
I was sailing along and tried to lower my keel. I turned the crank and suddenly heard a loud boom and after looking at the crank i saw that the cable had broken. Is there a keel still there or not? I docked the boat and felt underneath and could not feel the keel. Does the keel go back into the boat when the cable breaks, does it just hang there, or does it drop to the bottom of the ocean?
Help!

Don Lucier, Northstar
C25 SR/FK

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Dave Seely
1st Mate

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46 Posts

Response Posted - 03/23/2002 : 00:04:19

Kevlar is not a good choice for this application. The tensile strength of kevlar is about the same as e glass and its compressive strength is actually lower. Kevlar is much lighter though. A kevlar part can be thicker than an e glass part of the same weight, and therefore stiffer and stronger. An high strength carbon cloth would give the best strength for a given thickness but its very expensive and hard to find. Most of the carbon cloth on the market is high modulas rather than high strength. The best choice would be a stitched (non woven) biaxial cloth with epoxy resin. The adheasion to the original surface will likely be the biggest problem. All of the paint and gelcoat would have to be removed and the surface roughed up and cleaned with acetone. The reinforced area would have to be thick at the points of highest stress and gently tapper down as it gets further from the hinge point to avoid stress concentrations. Even after adding a couple of yards of cloth and a quart of epoxy, its still not likely to withstand the keel falling without some damage.

Dave Seely

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OJ
Master Marine Consultant

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USA
4382 Posts

Response Posted - 03/25/2002 : 10:30:58

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>

Who you kiddin Steve, you know shes the Admiral!!! and your the first mate!!

DW

<hr height=1 noshade id=quote></BLOCKQUOTE id=quote>

Foiled again!

Steve Madsen
#2428
OJ (Ode to Joy)

Edited by - on

OJ
Master Marine Consultant

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USA
4382 Posts

Response Posted - 03/25/2002 : 10:42:27

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>
Does the keel go back into the boat when the cable breaks, does it just hang there, or does it drop to the bottom of the ocean?
Help!
<hr height=1 noshade id=quote></BLOCKQUOTE id=quote>

I'd be surprised if the keel fell off, yes it's probably just hanging there. The C-22 keel weighs-in at about 1/3 that of the C-25. I think there would have been a telltale cracking sound if it had come off, plus the boat would be pretty unstable. We had a C-22 in our marina that had the winch cable let go (after he paid to have it inspected that spring) and he paid a scuba diver to attach a new cable to the keel.

If a keel (not center-board) ever fell off, does anyone know what's left of the boat would do? Wouldn't it just flop over or worse?

Steve Madsen
#2428
OJ (Ode to Joy)

Edited by - OJ on 03/25/2002 10:46:41

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