Boat Building Forum

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Re: Strongback Configuration
By:Paul Jacobson
Date: 7/13/1998, 3:15 am
In Response To: Re: Strongback Configuration (Mark Kanzler)

> Are you planning to run a 2x4 strongback down the centers of
> the frames like on a strip built as shown in Nick's book? Wouldn't
> all of thr forms be the complete shape of the boat at each section?
> It sounds king of like the forms you're doing are for just the hull
> or deck. Am I missing something? (besides a boat of my own)

>> Great minds (?) must think alike.

> And fools concur. ;)

I keep refering to this book by George Putz. You should break down and buy a copy. Even if you don't read it, there are plenty of pictures. :)

Sorry, I couldn't resist that.

Seriously. I misplaced my first copy of this book in mid-project, and just got another copy. It is a pleasure to read through.

Putz's book is based on his experience with building kayaks based on a model measured by a guy named Skeene, who was working off of a model owned by the Smithsonian. Pages from the original document are reproduced in the back of the book. The original forms were made of small pieces of lumber assembled into a roughly trapezoidal shape. Putz reproduces those shapes, cutting them from plywood.

The forms are set on the floor (or ground if you build outdoors) and are tall enough (about 35 inches) so that you work at a comfortable height.

My strongback is roughly ladder shaped: a couple of 2x8's spaced about a foot apart, with 2x4's nailed across. When I built the canoe I attached frames to the ``ladder rung'' 2x4s and lay strips over the frames. When I do the forms for this Greenland style kayak I'll make them shorter than Putz describes (20 inches shorter) and I'll respace (or add) some of the 2x4s on the strongback to get them spaced properly. Since I'm not building off of forms that go to the floor, but shorter ones, I use far less wood to make the forms.

These forms only define the bottom shape. The sides of the kayak are essentially straight, but at an angle to the bottom, giving a hard chined hull which flares to the waterline. The deck is whatever you want.

The sheer chine, which on a canoe would be a gunwale, can be placed anywhere along the side of the forms that you want, to give a boat of greater or lesser depth or displacement, but the measurements for the traditional depth are given. If you are a bigger than normal paddler, or planning to carry heavy gear, move them further from the bottom. Your boat will be slightly wider and deeper. You`ll sink a bit lower as you displace more water, but if you can calculate ( or estimate) how much freeboard you'll need, you can place that strip anywhere you want to get the desired result. Very simple.

Because the sides and bottom are essentially straight shapes they should be easy to duplicate with a stitch and glue design. The supports for the deck are simply hoops or bows, roughly semi-circular, with a radius of about 60 inches, if I remember the text correctly. You can steam-bend them, or cut them from a 1 x 8, or build them from thin, laminated strips. They attach to the gunwale and support some linear strips which in turn support the fabric. If you don't want a rounded deck, make it flat, or inverted 'V' shaped.

When you think about the origin of this craft, this seems like a pretty reasonable way to do things. If, instead of wood, you are working with bones from the rib cage of some dead sea mammal you have a lot of options here.

Hopefully some of this makes sense. Paul Jacobson

Messages In This Thread

Crooked Stitch and Glue Kayak Avoidance.
Mark Kanzler -- 7/12/1998, 9:59 am
Re: Crooked Stitch and Glue Kayak Avoidance.
NPenney -- 7/13/1998, 10:51 am
Re: Crooked Stitch and Glue Kayak Avoidance.
Don Beale -- 7/13/1998, 1:15 am
Re: Crooked Stitch and Glue Kayak Avoidance.
Rob Cochrane -- 7/12/1998, 11:06 am
Re: Crooked Stitch and Glue Kayak Avoidance.
Mark Kanzler -- 7/12/1998, 11:20 am
Re: Would a strongback really help though?
Mark Kanzler -- 7/13/1998, 11:46 am
Re: Would a strongback really help though?
NPenney -- 7/14/1998, 2:18 pm
Re: Would a strongback really help though?
George Burns -- 7/14/1998, 4:36 am
Re: Would a strongback really help though?
L.C. -- 7/14/1998, 10:02 pm
Re: Would a strongback really help though?
Wynne -- 7/14/1998, 2:14 pm
Re: Would a strongback really help though?
Mark Kanzler -- 7/14/1998, 11:43 am
Re: Would a strongback really help though?
Mark Kanzler -- 7/14/1998, 10:39 am
Re: Crooked Stitch and Glue Kayak Avoidance.
Scotty Morrison -- 7/12/1998, 7:04 pm
Greenland style S&G kayak from Putz plans
Paul Jacobson -- 7/12/1998, 9:10 pm
Delay on Greenland style S&G kayak from Putz plans
Paul Jacobson -- 7/14/1998, 12:26 pm
Re: Delay on Greenland style S&G kayak from Putz plans
Scotty Morrison -- 7/14/1998, 7:50 pm
Re: Strongback Configuration
Mark Kanzler -- 7/13/1998, 12:07 pm
Re: Strongback Configuration
Paul Jacobson -- 7/13/1998, 3:15 am
Re: Strongback Configuration (I Like The Looks Of This Method)
Mark Kanzler -- 7/13/1998, 4:32 pm
Re: Strongback Configuration (I Like The Looks Of This Method)
Hans Friedel -- 7/15/1998, 1:06 am
Re: Geoge Putz Book (what, no link?)
Mark Kanzler -- 7/13/1998, 1:36 pm
Re: Other George Putz Books
Mark Kanzler -- 7/13/1998, 1:40 pm
Re: Freeboard (no, not Lynard Skynard)
Mark Kanzler -- 7/13/1998, 10:42 am
Re: Freeboard (no, not Lynard Skynard)
Rob Cochrane -- 7/15/1998, 2:27 pm
Re: Freeboard (no, not Lynard Skynard)
Mark Kanzler -- 7/15/1998, 4:00 pm
Re: Freeboard (no, not Lynard Skynard)
Paul Jacobson -- 7/13/1998, 7:05 pm
Re: Freeboard (no, not Lynard Skynard)
Mark Kanzler -- 7/14/1998, 10:01 am