JEM Watercraft

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Author:  OnkaBob [ Tue Oct 13, 2009 10:31 pm ]
Post subject:  Hybrids

Been thinking about the pro's and cons of S&G vs strip and reading related threads and it occurred to me that a lot of Jem designs could be even better with a stripped deck. It's a matter of personal taste but I like the idea of building the hull without needing a strongback but then being able to have the chance to do some fancy artwork in strips on the deck.

I reckon the Laker, Freedom and even the Okwata would look good with a strip deck - possibly others too. Not sure how hard it would be to design some more frames to fit in the hull for building the deck but it should be possible(?).

I guess the snag is going to be instruction for stripping but as pointed out in the Freedom product information there is plenty of info out there on stripp building. It may serve as an entry level build for someone who wants to do a full strip build one day (like me) and it might sell a few more people on the Jem designs too.

Author:  jem [ Wed Oct 14, 2009 5:44 am ]
Post subject:  Re: Hybrids

it is a good idea. I'm trying to get back into adding more designs to choose from now that life has settled down a bit for me.

If there's enough interest, I can start a poll and have member vote on which current design they'd like to see a hybrid of first.

Author:  craiggamesh [ Wed Oct 14, 2009 10:22 pm ]
Post subject:  Re: Hybrids


I bet you could build a hybrid like you mentioned with only maybe an additional 10 hours of build time.

Here is an easy way to make your own "strip" plywood. The photos are from the bottom panel of my Touring Pirogue. I did the same for the sides and it is very simple and much faster than standard stripping. I am considering doing another kayak utilizing this method for all panels but the bottom. There is a lot of stress on the twisted bottom panels so I will stick to plywood for those. Besides, I have "seen the light" and have converted to the "dark side" or should I say "dark bottom" and have decided to apply graphite to the bottom of all my boats. Therefore, it would be, in my opinion, pointless to strip the bottom. I think the Laker would be an excellent Kayak candidate for attempting this method.

Just lay your plywood (or cheaper yet, oriented strand board) "template" panel out flat, cover with plastic drop cloth, strip on top of it, clean up the glue, and sand it smooth. Of course you would need to join your two 8 foot template panels to get one full length template panel. This also eliminates the seam which goes around the middle of the boat.
Then apply a layer of fiberglass cloth while its still flat. That will allow epoxy to flow into and fill any small gaps between strips. It also makes the panel into "plywood" securely holding the strips in place.
Trim flush to the template with a router and flush trimming bit. Stitch on just as you would with plywood.
I placed the glassed side to the inside of the boat so I didn't have to do that nasty interior fiberglassing. Just taped the seams. You can see the 2 side panels on the saw horses to the left of the last photo.

Author:  craiggamesh [ Wed Oct 14, 2009 10:27 pm ]
Post subject:  Re: Hybrids

I guess I should have read down to the bottom of the "active topics" list. Ron is building a boat using a similar method right now. I don't think anyone will be able to call it "ugly" when he gets done though! :D It will be another beautiful JEM stripper!

Author:  OnkaBob [ Thu Oct 15, 2009 6:06 am ]
Post subject:  Re: Hybrids

Craig, It's interesting that you should comment about the twist in some panels.

I have a perception that ply is going to resist breakage from being twisted better than a strip panel will. The grain in each ply runs in a different direction to the ones either side and it seems to me that this is going to be stronger for that particular type of distortion. Where the Laker has bend in one direction only and would probably suit strip panel construction even more than the pirogue, others like the Okwater look like there is some twist in the hull panels and it just may not work.

Let me stress that this is only a perception - I could well be wrong. Which brings me to Ron's build. I get the impression that he, too, is not sure how this will go but is willing to push the limits and find out for all of us. For this I am truly grateful and wish him success. If he pulls it off he may be deserving of what Michael Storer refers to as "Guru status".

Performance wise I think that a multi panel hull would come very close to a true compound curve hull - although again I'm just guessing. As for appearance, I am quite happy with hard chines on the hull but am not so keen on angled deck panels - again just a personal preference.

Getting back to the original idea though, my thoughts were not so much about doing the entire hull in strip panels but in keeping the ply hull and having the advantages of a strip deck without having to build a strongback. I figured some extra frames could be wired to the hull to provide support for the deck strips.

However, on reviewing Lee's strip decked Freedom build again today I noticed that he actually used a strongback. Matt, do you think this will always be necessary or would just wiring in some extra frames work OK?

Author:  tx river rat [ Thu Oct 15, 2009 11:51 am ]
Post subject:  Re: Hybrids

Strength wise the stripper have held up in many applications ,so I dont think that is a problem,and this will sound funny but if you look at the ply you really just have half the strength in each direction because of the direction of the grain. I did some test on some strips before I started and the titebond 111 glue it bonded so well I broke the strips sideways before the bond on the glue broke,also the glue line has some additional strength ,because it is a nondirectional section every 3/4 of an inch. In this design It doesnt have to much twist so I dont think that will be a problem.
This design is for mainly downriver racing, I got a education in the hard chined boat compared to the round shaped stripper, Darrel was in his Freedom and I was in the T-V ,we paddled up the river a few miles,in the swift water he was having a much easier time and his boat was faster ,but when we turned around and started down river the T-V would outrun his boat. Matt had told us but it really was driven home that day..
I really am confident this will be a succesful build,cheaper than buying marine ply,no worrys about ply delaminating or voids,simple with a good set of plans like Matts, no strongback,much greater choice of wood colors than ply.
This boat will be built with just the normal frames
A name for this construction might be fun lets see double hybrid stich and glue stripper

Author:  LIGHT KEEPER'S KID [ Thu Oct 15, 2009 12:22 pm ]
Post subject:  Re: Hybrids

I think because of the high costs of marine ply that striping is the way to go :wink:


Author:  OnkaBob [ Thu Oct 15, 2009 4:25 pm ]
Post subject:  Re: Hybrids

Some more interesting points there Ron. I think many of us know that a glue joint is often stronger than the base material but I had not considered that it acts as a plane of composite material and would therefore strengthen a panel. This method is sounding betterer and betterer :D .

How do you think you will go stripping the deck without extra frames - or is it a case of using the premade strip panels again?

The cost of marine play is another thing - here in Aus the price has come down significantly in the last few months. Now it's just "bloody expensive" instead of "totally ridiculous"! :roll: We have a good supplier of Paulownia (although he is interstate) and I am dying to make a boat out of it. The potential to make any design out of this lightweight wood now opens up more possibilities as weight is important to me and rules out a number of models. haven't done exact calculations yet but I think the cost of Paulownia would be comparable to good quality marine ply for a given boat.

As for a name , just add an S to S&G to give SS&G or SSG (Strip, stitch and glue). 8)

Author:  craiggamesh [ Fri Oct 16, 2009 2:02 am ]
Post subject:  Re: Hybrids

I really am confident this will be a succesful build,cheaper than buying marine ply,no worrys about ply delaminating or voids,simple with a good set of plans like Matts, no strongback,much greater choice of wood colors than ply.
This boat will be built with just the normal frames

I agree with Ron about the cost of marine ply.

The cost of marine ply and my curiosity is why I built my Touring Pirogue with strips. Also, I could not find any good Luaun ply for some reason. I would say making the strip panels only added an additional 10 hours to the build.

I can't wait so see your results Ron

Author:  Phishtech [ Tue Oct 20, 2009 9:59 pm ]
Post subject:  Re: Hybrids

I tell you what fellas, I've followed Ron and his work on 3 different forums now, and the more I read what he has to say, the more I realize that although he sounds like he didn't get a high level of education under his belt, he just happens to be one of the smartest people that I know (although I've never met him in person, yet). Keep up the good work, Ron, and I hope to paddle with you someday on the Brazos.


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