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70's Hobie 12 Monocat
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Author:  HARDaLEE_Hondo [ Sat Aug 20, 2011 9:46 am ]
Post subject:  70's Hobie 12 Monocat

About 10 years ago my wife picked up a Hobie Monocat at a garage sale for $20. Her dad helped her pick it up and together they placed it on top of his suburban and dropped it off at her grandfathers property. It remained there until a few months ago when she told me the story. I set out with a machete and an ax and ventured into the LA swamp/jungle to find this lost treasure. After about an hour of hacking and chopping I was able to extract the boat and look it over. The only piece missing was the rudder, the sail was in great shape. There was one small crack in the transom area of the starbord hull, the deck was nearly perfect. The little cat was so covered in overgrowth it couln't have been better preserved had it been stored indoors except for one minor detail; The port, aft cooler lid had been left open. That boat that had been lifted on top of a suburban now weighed over 300lbs. With much sweat, cursing, and a little Give-m-heck Marine attitude (aka: Temper) I was able to get it wrestled into the back of my pickup. When I got it home to Wyoming I drilled a series of small holes in the bottom and let it set in the hot, dry, summer sun for a few months. Near as I could figure I had shed nearly 100lbs of water. After plasti-welding the holes shut and fashioning a crude rudder I took her out for a sail on the lake. My weight, nearly 200lbs, plus the weight of the water was still to much for the small craft. She sailed ok for about 2 hours before she took on more weight than she could handle. I beached her, propped up the bow 3' in the air, pulled the plugs and let her set in the sun again.

Determined to find a way to fix up this neat little boat I began to search the web. I was surprised at how little I was able to find. To my knowledge, no one has ever successfully taken the deck off, dried it out, and reattached it. Since I've got a total of $0.00 in the boat I figured I wasn't out much to give it a shot. If nothing else I'll save the hardware and put it on another project.

This is what I've found...

The deck is glued to a contoured piece of foam roughly 2" thick. This is glued to formed foam that fills the hull. The hull foam contains compartments roughly 1' squair. Towards the bow, glued inbetween the deck and hull foam, is a wooden spar that the mast base attaches to.

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My First mistake was thinking I could separate the thin plastic deck from the 2" foam deck piece that it is glued to. I cracked it in several places. I figued at this point that it was no longer usable so I went ahead and removed it in pieces.

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I believe that you could actually take this boat apart if you tried to pull the deck and its foam from the hull and its foam, rather than taking just the deck IMO.

Here you can see the hull and the foam:

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Here is the Foam deck piece:

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This piece of foam alone weighed over 80lbs!

Here is the wooden structure that supports the mast:

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Here is a comparison to show you the wieght of waterlogged foam:
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The piece of foam weighs roughly the same as the similarly sized piece of wood!

Here is another comparison:
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The volume of foam for this cooler and these pieces are roughly the same. The cooler (with plastic handles) weighs 9oz, the wet foam weighs almost 3 lbs! That means that the foam pieces could be holding nearly 3 pints of water!

As an experiment, I've left a few of the foam pieces outside in the sun to dry. By my calculations if one were to successfully separate the hull and deck, leaving the upper and lower foam attached to their respective pieces, you could, in theory, dry the boat out in a matter of 6 weeks...

Author:  dregsfan [ Sat Aug 20, 2011 7:23 pm ]
Post subject:  Re: 70's Hobie 12 Monocat

Very cool! Thanks for posting this. I had a Monocat a couple years ago. The deck was pretty fractured, but the hull was good. I ended up selling it without every sailing it.

Author:  HARDaLEE_Hondo [ Sun Aug 21, 2011 9:14 pm ]
Post subject:  Re: 70's Hobie 12 Monocat

I figured out that you can take out the swing keel "trunk" piece off of the hull. Here I found a pretty good crack:

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Looks like this area might need a little reinforcement...

I've run through several ideas, but the best I can come up with is to use the large deck foam piece to make a new fiberglass deck and cut new foam for the hull. I'll keep posting pics of the progress!

Author:  trawler85 [ Fri Sep 23, 2011 1:53 pm ]
Post subject:  Re: 70's Hobie 12 Monocat

Hello, we are both trying to do the same thing. I just picked up a monocat today and every bit of 300 lbs. It took 3 of us to stand it on end against a wall in my shop. I am hoping I will not have to separate the hull. I am going to try to ventilate with a small fan through one of the rear ports to see if it will dry out but I have my doubts. Hope gravity and time will do the trick. Will be following your post . Good luck

Author:  dorienc [ Mon Jan 02, 2012 5:48 pm ]
Post subject:  Re: 70's Hobie 12 Monocat

I had a monocat for my son some years back. I wondered why it was so heavy-it seemed to weigh as much as my 17! I wonder if it could be vacuum bagged to pull the water out of it?

Author:  MBounds [ Tue Jan 03, 2012 5:10 am ]
Post subject:  Re: 70's Hobie 12 Monocat

You'd probably collapse the deck / hull in the process. There's really no cure for the waterlogging that plagued the Hobie 12 and Hobie 10. That's one of the major reasons they were only made for a few years.

Author:  Bacho [ Thu Feb 02, 2012 12:30 pm ]
Post subject:  Re: 70's Hobie 12 Monocat

Might sound stupid but what about using something to dissolve the foam and them pouring new foam in?

Author:  Mugrace72 [ Sat Feb 04, 2012 12:11 pm ]
Post subject:  Re: 70's Hobie 12 Monocat

The sad part of this is that they really weren't very good boats even when new. I know because I sold them and virtually every one had issues right from the start.

We actually took a few back and refunded the money. There is really no way to properly repair these boats.

I think this is a subject that Hobie would like to forget ever happened.

Author:  augaug [ Sat Feb 04, 2012 7:43 pm ]
Post subject:  Re: 70's Hobie 12 Monocat

Seeing this makes me love my Bravo even more. Wow.

Author:  Lone Palm [ Mon Feb 06, 2012 12:38 am ]
Post subject:  Re: 70's Hobie 12 Monocat

I grew up sailing a 12. We toasted the Sunfish crowd and most of the Lasers out at the time.... We could flip her over, scramble up on the bottom, and with luck flip her back upright without getting more than our legs wet.....

That was a long looong time ago, but they will always have a place in my heart.... 8)

Author:  Cattleya [ Mon Oct 08, 2012 7:09 pm ]
Post subject:  Re: 70's Hobie 12 Monocat

My wife bought a Hobie 12 (monocat) new...and we still own the boat. It was a joy to sail. Ours is waterlogged like most of them and I intended to try to repair it someday. Thanks very much to Hardalee_Hondo for all the photos. They will be very helpful if I ever try to tackle the project. And if I do, I'll know to avoid intentionally separating the deck skin from the attached foam. Any advice about removing the perimeter rub-rail at the deck-hull joint, or about separating the joint?

Author:  LoHobie [ Wed Jan 21, 2015 12:25 pm ]
Post subject:  Re: 70's Hobie 12 Monocat

I know this thread is a couple of years old, but it is worth a shot.

I just picked up a Monocat 12 that was sitting since 1980, but was in a covered shed. It was then given to the person I bought it from, who stored it in their yard and left it to be rained on for a couple of months. It was full of water, but only for a couple of months. I tipped it on end and a lot of clean water poured out.

Does anyone know how quickly the styro soaks up water? If it takes a while, I may have gotten lucky. The orange plastic is pretty cracked and I will have to replace it.

Having read this thread, it has been said that there is no way to repair these waterlogged boats. Could one clear out the hull and build a more traditional frame and deck to fit in, bonding the framing to the hull for the rigidity? Also, could one cover the styro with epoxy and cloth to seal it? And if one wanted to store it outside, would storing it hull side up solve the problem?

Thanks!

Author:  moncasta [ Tue Jan 27, 2015 7:31 pm ]
Post subject:  Re: 70's Hobie 12 Monocat

The foam would melt under the layup process of regular fiberglass work. The plastic is brittle deck and hull and as shown in other parts of this and a few other threads... basically it was a really bad design, and nobody has a good answer on how to get some use out of this boat.

The foam will soak up water during a day of sailing, you can leave it tipped up on end and sitting for a few months to get moisture mostly out, and fill it up again after a day of sailing.

It's a cool little setup, I tried to use some epoxy to fix cracks, and some griptape over epoxy to give a little more reinforcement. Ultimately I was moving the boat, and it flexed and broke in half, a previous owner had squirted a bunch of epoxy into the hulls and melted the hell out of the foam inside.


I've got two sails, spars, dagger and rudder if you need some parts ;).


Tom

Author:  ronholm [ Tue Jan 27, 2015 7:58 pm ]
Post subject:  Re: 70's Hobie 12 Monocat

??


Author:  ocnsky [ Wed Jan 28, 2015 1:58 pm ]
Post subject:  Re: 70's Hobie 12 Monocat

Follow, interested in using acetone and creating a mess. I have a terribly waterlogged hull as well.

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