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by DaleYoung. 06/14/22 08:16 PM
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Hull Foam #89989
11/17/06 04:41 PM
11/17/06 04:41 PM
Joined: Jun 2001
Posts: 493
Minnesota
Jeff Peterson Offline OP
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Jeff Peterson  Offline OP
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Joined: Jun 2001
Posts: 493
Minnesota

There has not been much discussion about the foam, in the foam/fiberglass sandwich that makes up the Hobie hulls. There has been lots of discussion about the delamination that results from the failure of that foam. And there have been suggestions that the foam of the early 80s was of lower quality, and specific discussions about the red glue line hulls and changing hull weights.

So what is the history of the Hobie hull sandwich and the foam filling???

How has the foam and the sandwich construction changed over the years?
Has the construction consistently improved?
Have past efforts been made to improve the bonding between the foam and resin?
Have past efforts been made to reduce the damage caused by internal hull moisture?
Why dont H-16s have factory installed ports to allow dry-out of the hulls?
Has the thickness of the sandwich change over the years?
Is susceptibility to walking-on-the-hull damage a significant concern, and has that susceptibility changed over the years?

Let the discussion commence!


Jeff Peterson
H-16 Sail #23721
Big Marine Lake, MN
-- Have You Seen This? --
Re: Hull Foam [Re: Jeff Peterson] #89990
11/17/06 07:47 PM
11/17/06 07:47 PM
Joined: Nov 2005
Posts: 5,582
“an island in the Pacific....
hobie1616 Offline
Carpal Tunnel
hobie1616  Offline
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Posts: 5,582
“an island in the Pacific....
Take a look at the Hobie Forum to answer most of your questions. Go through the 16 forum first.

http://www.hobiecat.com/community/index.php?c=N


US Sail Level 2 Instructor
US Sail Level 3 Coach
Re: Hull Foam [Re: hobie1616] #89991
11/17/06 08:09 PM
11/17/06 08:09 PM
Joined: Oct 2006
Posts: 902
Norman,OK
gree2056 Offline
old hand
gree2056  Offline
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Posts: 902
Norman,OK
I loved my little Hobie 14... but I am really looking forward to not having to worry about stepping on my hulls with my Nacra.
I know that the idea of inspection ports sounds like a good idea, but they leak sometime which actually furthers the problems.
It seems to me that after 30??? someodd years of making a boat there could be a way to prevent the delam.


Once you go cat you never go back! Nacra 5.2 (Elsies)#1499, running an inter17 spin!
Re: Hull Foam [Re: gree2056] #89992
11/17/06 08:25 PM
11/17/06 08:25 PM
Joined: Nov 2005
Posts: 5,582
“an island in the Pacific....
hobie1616 Offline
Carpal Tunnel
hobie1616  Offline
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“an island in the Pacific....
Quote
It seems to me that after 30??? someodd years of making a boat there could be a way to prevent the delam.
The current discussion on the Hobie forum indicates that boats built after 1980 have a very small incidence of delam problems. The exception is when the boat is stored with the drain plugs in for extended periods of time.

http://www.hobiecat.com/community/viewtopic.php?t=5327&sid=9436946f7311aaa47554eb9524d8f38d


US Sail Level 2 Instructor
US Sail Level 3 Coach
Re: Hull Foam [Re: Jeff Peterson] #89993
11/17/06 10:51 PM
11/17/06 10:51 PM
Joined: Sep 2005
Posts: 1,187
38.912, -95.37
_flatlander_ Offline
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_flatlander_  Offline
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Posts: 1,187
38.912, -95.37
Quote
And there have been suggestions that the foam of the early 80s was of lower quality, and specific discussions about the red glue line hulls and changing hull weights.


From what I've been told by reliable sources, all the 16's I've seen over the years and information from the forums;

Late 70's decks we're prone to softness. Don't know why. People complained. The '80, '81 (I bought one new), were tanks. Solid decks and over minimum weight. People complained. Weight came down in '82, '83. Solid decks. Coleman boats begin in '84 & '85 and identified by serial number, Coleman sticker on the transom and red glue in hull to deck seam. Weighed at minimum weight. Solid decks. Since then weight has fluctuated a bit, and decks are stout (depending on care or lack of).

If you leave water in the hulls all bets are off.

When looking to buy ANY Hobie 16 check the decks, if they are soft, walk away. There are a cajillion more to look at.


John H16, H14
Re: Hull Foam [Re: _flatlander_] #89994
11/18/06 03:39 PM
11/18/06 03:39 PM
Joined: May 2006
Posts: 1,383
Kingston SE South Australia
JeffS Offline
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JeffS  Offline
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Joined: May 2006
Posts: 1,383
Kingston SE South Australia
If you get the boat cheap enough and its only the decks that are soft its not hard to cut the decks off put and some foam or 4mm ply bulkheads in. Then turn the old decks over wessystem 8mm davinacell foam, then cloth on. The foam can be ordered with slits so that it curves to the shape of the old deck easily and doesnt pull the deck out of shape. Then make a lip around the cut with foam and cloth sit the deck back on wessystem the deck back on. You can now dance on the boat for hardly any extra weight. Avoid deck ports anywhere near where you might put weight. Ive just done all this including the cheap boat
regards <img src="http://www.catsailor.com/forums/images/graemlins/smile.gif" alt="" />


Jeff Southall
Current boats
Nacra 5.8 1703 Animal Scanning Services
Nacra 5.8 1667 Ram Raider
Nacra 18 Square
Arrow 1576
Re: Hull Foam [Re: _flatlander_] #89995
11/18/06 04:32 PM
11/18/06 04:32 PM
Joined: Jan 2004
Posts: 1,884
Detroit, MI
mbounds Offline
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mbounds  Offline
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Joined: Jan 2004
Posts: 1,884
Detroit, MI
Quote
Late 70's decks were prone to softness.

Yes, but only after many years of (ab)use - the Hobie warranty is five years. I don't know of any warranty claims for delamination. Matt Miller may have some history on this. I owned a '78 and raced it hard for six years. No problems.

Quote
Don't know why.

Speculation is that the foam core did not allow the layup to adhere to it as well as later foams. Matt Miller confirms that the type/brand of foam was changed in the '80's.

Quote
People complained.

ORLY? If you buy a boat that's out of warranty, then you have nobody to blame but yourself for not inspecting it thoroughly.

Quote
The '80, '81 (I bought one new), were tanks. Solid decks and over minimum weight.

Min weight at the time was 340# Most boats of that era still weigh less than 355#. Boats were not regularly weighed then because the nationals had provided boats.

Quote
People complained.

About what? Most people had no idea what their boat weighed.

Quote
Weight came down in '82, '83. Solid decks.

Nope. Manufacturing process was changed for the 1984 model year which resulted in a significant reduction in weight. Class min weight was changed in 1985 to 320#, where it remains today.

Quote
Coleman boats begin in '84 & '85 and identified by serial number, Coleman sticker on the transom and red glue in hull to deck seam.

Wrong again. Coleman bought Hobie Cat in 1976. Red glue seam was indicative of the 1984 manufacturing process. Hull graphics changed in 1984 and included the Coleman stickers. Coleman sold Hobie Cat in 1988.

Quote
Weighed at minimum weight. Solid decks.

Actually, the '84/'85 boats were less than minimum. I owned an '84 that had lead shot in the rear pylons (from the factory) to bring it up to minimum. I own an '85 H-14 that weighed 8 lbs less than minimum before I put a dolphin striker and a trapeze on it. My '84 16 was a bit fragile - two pylons came loose and had to be repaired.

Quote
Since then weight has fluctuated a bit, and decks are stout (depending on care or lack of).

Actually, weights crept up from '86 to early '90's because of the warranty claims for fragility. (I owned an '89 that weighed 345#) In the meantime, the H-16 became an ISAF International Class, and the class rules became subject to ISAF oversight. In 1990, Hobie Cat stopped providing boats at nationals and boat weighing became more commonplace. In 1991, sailors and ISAF exerted pressure on Hobie Cat to produce boats at minimum weight, which they agreed to. Since '92, boats have been generally at minimum weight, and the weights of the hulls are engraved behind the rudder pins. (Most hulls weigh between 68# and 72#)

In summary, delamination occurs on the 1970's boats because they're old. Nearly 40 years of flexing on the decks breaks down the bond between the glass and the foam. Once it starts, it's like cancer. You can fix it in one area, and it'll pop up in another.

Re: Hull Foam [Re: mbounds] #89996
11/19/06 10:54 AM
11/19/06 10:54 AM
Joined: Sep 2005
Posts: 1,187
38.912, -95.37
_flatlander_ Offline
old hand
_flatlander_  Offline
old hand

Joined: Sep 2005
Posts: 1,187
38.912, -95.37
Thanks for ALL the clarifications, Matt.

What do they say? Only beleive half of what you read <img src="http://www.catsailor.com/forums/images/graemlins/blush.gif" alt="" /> <img src="http://www.catsailor.com/forums/images/graemlins/blush.gif" alt="" /> <img src="http://www.catsailor.com/forums/images/graemlins/blush.gif" alt="" />

Quote
I owned an '84 that had lead shot in the rear pylons (from the factory) to bring it up to minimum.


This is interesting. My first instinct would say add the weight at the front pylon. Any particular reasoning behind this that you know of?

Thanks, again

Last edited by flatlander18; 11/19/06 10:55 AM.

John H16, H14
Re: Hull Foam [Re: Jeff Peterson] #89997
11/20/06 07:41 AM
11/20/06 07:41 AM
Joined: Jul 2001
Posts: 206
Virginia USA
CMerrell Offline
enthusiast
CMerrell  Offline
enthusiast

Joined: Jul 2001
Posts: 206
Virginia USA
<img src="http://www.catsailor.com/forums/images/graemlins/shocked.gif" alt="" />

Re: Hull Foam [Re: CMerrell] #89998
11/20/06 07:45 AM
11/20/06 07:45 AM
Joined: Jul 2001
Posts: 206
Virginia USA
CMerrell Offline
enthusiast
CMerrell  Offline
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Joined: Jul 2001
Posts: 206
Virginia USA
Don't know what happened to my text!

Attended a regatta this year in which the bow of a '70s-era H16 snapped off. The deck foam was obviously brown and deteriorated but the hull foam/glass was pristine; looked like it had just left the factory. I was impressed that the foam of a 30 YO boat would look that good.

Re: Hull Foam [Re: CMerrell] #89999
11/20/06 01:23 PM
11/20/06 01:23 PM
Joined: Jun 2001
Posts: 1,252
California
mmiller Offline
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mmiller  Offline
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Joined: Jun 2001
Posts: 1,252
California
Just a bit more on the foam issues...

Back in the early days Hobie Alter was making balsa core surfboards. He created the foam core board process and his buddy Gordon Clark took on the business of making the (Polyurethane) foam. The foam Hobie used in the cats was the Clark Polyurethane foam for many years. Clark used to make the foam in large loafs, then the loafs were sliced like bread. Lower layers were more dense and throughout it varied. That seems to have made some of the difference over the years. We quit using Clark foam back in the early 80's. We have been using a PVC foam for many years without the original problems from the 70's.

Weights...

In the 1984 model year Hobie Cat took some steps to lower the weights of hulls. The change in process was marked by the addition of a red dye in the glue seam process. The new process involved a different glue seam technique, better control of excess resin and in some cases (Hobie 18) a change in the amount and location of the glass layup. The Class rules were fixed and needed to change, but Hobie Cat began using the new processes. To keep the hull weights at the minimum levels per the class rules, some boats had lead shot added in the rear pylon (for a short period). Why rear?... weight aft is a GOOD thing. Some people were able to chip out the weights after the rules were changed. Hobie 16 class weight went from 340 to 320 pounds.

Re: Hull Foam [Re: mmiller] #90000
11/20/06 02:33 PM
11/20/06 02:33 PM
Joined: Jun 2004
Posts: 393
Syracuse,N.Y
pbisesi Offline
enthusiast
pbisesi  Offline
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Joined: Jun 2004
Posts: 393
Syracuse,N.Y
84 H16 with red glue. Weighed 321 at the 93 Nationals.
The shoe is cracked as you can see.
I repaired both hulls this spring with West System.
The decks on this boat are solid. Good for another 10 years of Fleet racing.
[Linked Image]


Pat Bisesi Fleet 204
Re: Hull Foam [Re: pbisesi] #90001
11/23/06 03:46 PM
11/23/06 03:46 PM
Joined: Feb 2005
Posts: 4,118
Northfield Mn
Karl_Brogger Offline
Carpal Tunnel
Karl_Brogger  Offline
Carpal Tunnel

Joined: Feb 2005
Posts: 4,118
Northfield Mn
When was the last time you bought anything, and expected it to last more than 10 years? I plan on trading/selling my H16 in 2008. I like new things, can't afford a new truck at 50k that often so my as well replace the boat every three years for a few thousand dollars.


I'm boatless.

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