And Now, A folding Pirogue.... | SouthernPaddler.com

And Now, A folding Pirogue....

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islandpiper

Well-Known Member
Jul 6, 2006
2,556
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Ponchatoula, Louisiana
www.islandpiper.com
Last summer I built two matching U J Pirogues concurrently. When they were done I found that they nested really nicely.

How about this.....build a U J Pirogue, but without the varnish for now.....then just off the middle point add two light, strong divider bulkheads, about one saw-blade thickness apart. Fit them in after all other glassing, etc is complete, epoxy them in, fillet the exposed sides, glass tape, etc. Mark and drill 4-5 places through both of them together for 3/8 " bolts with rubber gaskets and big wing nuts. Then cut the boat into two parts between the bulkheads. Epoxy the raw edges, and finish varnishing, etc. If done in the right spot this should give one half that will nest into the other half pretty well and fit into many SUVs, light trucks and even condo's and apartments, dorm rooms, etc. Seems to me if the bottom and sides were joined well and "happy" as one unit, they won't change as two units as long as the bulkheads are solid.

Pretty tempting idea. If Jack had a Pirogue we could experiment with it.

Piper
 
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cctyer

Well-Known Member
Apr 20, 2007
248
0
Short Shorts, Arkansas
Me likes where your going with this Piper! I think I can get a picture of what your talking about in my head BUT your gonna need to draw a picture for all the yankees up north to follow. Especially Jack!


Psst- He is a little slow with the technical stuff so take it easy on him OK :wink:
 
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Kayak Jack

Well-Known Member
Aug 26, 2003
13,976
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Okemos / East Lansing Michigan
In Sault Sainte Marie, Canada, is a Bush Plane Museum. In there is a canoe that dissembles. It breaks down to three pieces - two ends and a mid-portion. One end is quite short, the other end is long enough so the first end will fit inside it, and short enough to fit inside the mid-section.

If a builder were to separate boat sections with bulkheads, all bulkheads should be well braced for a horizontal load that would tend to rip them out sideways under load.

Do NOT be lulled into a false sense of confidence by trying to compute "normal load and length of lever arm" loads. What will snap one out will be an instantaneous shock load, that happens all of a sudden, and unexpectedly. Brace it for maximum shock load, and hope it's a waste.
 
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Kayak Jack

Well-Known Member
Aug 26, 2003
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Okemos / East Lansing Michigan
VERY plausible, Piper San. Very useful too. It does make certain load or passenger configuration a bit more limited, but a lot better than not having any boat at all.

Nesting boat sections is something that Matt has toyed with too.
 
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seedtick

Well-Known Member
Jul 22, 2006
1,161
7
Denham Springs, LA
Good idea

I have to agree with Jack, there's a lot more shock load and torsional rotation than one would expect. Especially where the two now rigid pieces come together. Not that it couldn't be overcome, just that I'd expect the bulkheads to be at least 1" thick. Probably not good for all y'all wanting a 25 pound boat.

it would be an interesting experiment
 
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BobR

New Member
May 9, 2007
2
0
Sarasota, FL
www.bobsteardrop.com
Nesting is a building method that is not to difficult. Here is an example of a dingy built using the same technique.


smdinghycut1.jpg


smnestedwithoars.jpg
 
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Kayak Jack

Well-Known Member
Aug 26, 2003
13,976
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Okemos / East Lansing Michigan
Leave us separate two, distinctly different, concepts here - folding and nesting. Folboat is a good example of a folding boat. It doesn't nest. The pictures of the two-part dinghy with the fore part setting inside the aft section is a good example of nesting.

Seedtick may be correct that a bulkhead should be 1" thick; I hope he's wrong. I think that bracing around the perimeter of the bulkhead would make up- for thickness - and then some.

The middle of the bulkhead could be cut out - either as a hole in the middle like a large "D", or as a large "C" lying on its side. All strain would occur at the perimeter of the bulkhead, not in the center. With two abutting bulkheads, one should be a "D" so as to provide a thwart, but no need for both bulkheads to have the thwart crosspiece across the top edge.

While Seedtick certainly has a helluva lot more experience than I do at hand building wooden boats, I'd start with 3/8" plywood for my bulkheads. I think that triangular angle braces degree triangles of 3/8" plywood) along the perimeter of the bulkhead would provide the stiffness needed. I would expect a ring of, say, 4" height should suffice nicely, if well braced every 8" - 10". These bulkheads would benefit by having double thickness at points where there are bolt holes to bolt the sections together.

The strain factors I envision would try to bend the canoe either up or down. Some torsional force would exist in white water, or if carrying a loaded canoe with men on opposite sides fore and aft. But, the primary devilment would come from, say, bridging one end on a shore and the other in the water with the mid-section unsupported, paddling over a beaver dam, over a log, or picking up a loaded canoe.

Again, though, Seedtick has more experience than I. (I'm wanting to be the better looking us two, but don't hold out much hope there either.)
 
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oldsparkey

Well-Known Member
Aug 25, 2003
10,479
123
Central , Florida
www.southernpaddler.com
Guy's ...

I hate to say this ... NO ...Actually I am enjoying telling all of you this. :lol:

A few years ago someone got one of the Uncle John Pirogue kits and made a take apart pirogue. He divided it into one large and one small section so it would nest together and fit in the back of his pick'em up. That is a truck for any Yankees on here.

Where he made the cut he put in a bulkhead and on the forward portion of the two halves he ran a small lip back to fit up against the hull from the other part. Then around the two bulkheads there was a narrow strip of foam rubber and 6 bolts with wing nuts and washers to attach the two sections.

I have been trying to locate the information on how he did it and have had negative results on locating it but I remember most of it because of the idea. Same as when the one guy who made a Pirogue at 25 feet so he can take tourists in the Louisiana bayous sightseeing. Take a standard Pirogue and proportionally stretch it to 25 feet. :D

Chuck.
 
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BobR

New Member
May 9, 2007
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0
Sarasota, FL
www.bobsteardrop.com
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seedtick

Well-Known Member
Jul 22, 2006
1,161
7
Denham Springs, LA
Having never built one of these, I'm far from an expert............

My idea of a thick bulkhead was more or less based on the surface area of the sides touching the stem. Say you have a couple of inches of surface contact where the sides join the stem. Why wouldn't you want that type of contact on a bulkhead that will see a lot more leverage than the stem?

I'm a belt and suspenders type person and i wouldn't feel real good about edge nailing and/or gluing 1/8 or 1/4 plywood to a 3/8 or 1/2 plywood bulkhead.

there's always more than one way to skin a cat (or build a bulkhead) and i would be very interested to hear others thoughts or details of a boat like that in service
 
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Kayak Jack

Well-Known Member
Aug 26, 2003
13,976
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Okemos / East Lansing Michigan
Seedtick,

I certainly understand your concern about footprint area of contact along the edges of a bulkhead. Darned good point. My hope was, that the triangular braces would supply that, maybe not. Making the bulkhead a "D" to provide the thwart would help stiffen it up too.

Mayhaps the only way to find out is your "by hand & eye" method. (My uncle used to say, "By guess and by God.") IE: actually construct one - or a mock up - and tear it to destruction to see.

If, in between the triangular braces, some quarter round were butted up against the bulkhead, that would double or triple the footprint. Maybe that would add the strength your want. I sure as hell agree with a "belt and suspenders" philosophy. Hull integrity is a strong passion of mine.
 
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islandpiper

Well-Known Member
Jul 6, 2006
2,556
4
Ponchatoula, Louisiana
www.islandpiper.com
hey tick, when you stop into the shop I'll show you hw we glue the edge of a .87MM rib onto a violin back or top.....by using a lining about 1.0 mm thick which gives us a place to glue without much added weight or stiffness.

I suspect that the bulkheads could be 1/4" ply with 13 inch siffeners at the edges.

Piper
 
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cctyer

Well-Known Member
Apr 20, 2007
248
0
Short Shorts, Arkansas
Ah Ha Piper good point . But when was the last time you saw someone Paddling a nested violin around? :lol:

Sorry I could not resist. carry on math magicians i'll go back in the corner with the cap now.



Jack was on to something when he said I had that shite eatin grin.
 
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