Pram Design Help Wanted/Needed!

Hi All!

I'm wanting to build a ~10pram for hunting with my dog 'round lake/marsh margins and for  crossing the river and mellow water anchoring and fishing.  I weigh 220#; dog=100#; gear 50-100#.  So, I'm looking for something to safely float ~400-450#.

I'm thinking that I need a compromise.. neither a river runner, 'nor a long distance racer.  I just want to paddle/row ~100-200yrds to get where I and others can't go with waders.

This is modeled so that the wide transom is headed downstream, when drifting; or when rowing somewhere, the narrow transom it headed in the direction of travel.

I first modeled a Hudson Springs Pram:  http://www.duckworksbbs.com/plans/messer/hudson_springs/index.htm

I modified it by raking back both transoms, for river use.  I then widened the sides and freehand cut a bottom out and created the sides and transoms to fit.

I don't know how to use the FreeShip software.  I might figure out Hull.  But I need some sound advice on how to modify what I have.  I've attached pics.

1"=1'   So the bottom=8", or 8' long;  Bottom is 45" wide;  Narrow transom is 27" at bottom;  Wide transom is 40" at bottom;  Beam is~ 66";  Transom top to top is 9'10.5"; Sides are ~18-19" actual height/width and just shy of 10' long.

There's some rocker in this, but not much.  I'm thinking I could easily narrow the narrow transom some and a touch on the wide transom.  I'm thinking that this is way overbuilt for the weight I've given above.

Could I go narrower than 45" overall?  I've seen prams from 38.5" to 48" wide.  Could I go a little shorter on the side height?   I'm really open to all ideas!

Many thanks!   Ken

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Permalink Reply by Ken Shindledecker on November 12, 2013 at 7:34pm

Yes,, it's coming down to some sort of boat, similar to this Mekong boat,, only much shorter and a bit wider.  My real concern is building something that is neither too big, nor too small... mostly, not too small and unusable.  So I'm wanting to get a handle on some basic dimensions.  Would a 12'x42-43" Jon-Pram, kindof similar to the boat below have enough displacement??

Dorf:  Outrigger's a neat idea,, but it won't work in this situation, going through the reeds and grass.. But thank you! 

Permalink Reply by John Weston on November 12, 2013 at 7:38pm

Ken, I like the idea of the backwater 15. I would make the gunnel at 44" an the bottom at 40". make the transom width at 30" top an bottom the bow at 18". keep it at 14 or 15'. do a model an see how it works out. may work out.

JW

Permalink Reply by Ken Shindledecker on November 12, 2013 at 7:47pm

Thank you!!   Is there any way to approximate the weight and if it will safely carry ~400#?

I've given up on the multiple use idea,, and like the drift pram I've modeled.  But for marsh uses, I'm liking this idea!  I would only have one rail 'round the top and one seat.  I might either put in a couple/few ribs, or those neat triangle supports that Warren Messer uses in his Hudson Springs Pram.  http://www.duckworksbbs.com/plans/messer/hudson_springs/Boat-Interi...

I was thinking of running a strip around the inside, on which I could set a board seat?.. Maybe I'd want something more substantial.

I was also thinking of just glassing the seams and Coat-It the bottom,, or maybe add a layer of glass cloth to the bottom as well,, but just paint, or oil the sides??  I'd like to keep the weight down.

Oh..... And I thought of keeping less flare at the back, so I could paddle and starting more flare in the front 1/3??  Silly/stupid??

Again,, thanks!

Permalink Reply by Ken Shindledecker on November 13, 2013 at 8:38am

JW:  I was looking at more canoes and given the dimensions of this 12' Old Town canoe and its capacity, the figures you gave should surely float me 'n the dog and gear ~400#!

http://www.oldtowncanoe.com/canoes/recreation/stillwater_12/

Permalink Reply by John Weston on November 13, 2013 at 8:57am

Ken, should be no problem. I would build a model and see how it looks. should be a great marsh boat and you can also pole it.

JW

Permalink Reply by Ken Shindledecker on November 13, 2013 at 9:30am

What,, no cute Mekong boat girl??!  ;-)

So, how efficient is poling?  It might be a good idea to have one for certain places, as in the reeds and weeds.

Do you think I could keep the boat under 100#, if I take it to 15'?  I'm kind of considering the 14',, though I know, the longer the more glide.

Permalink Reply by John Weston on November 13, 2013 at 9:48am

hmm, Mekong boat girl. well, when I was running around the delta in 66 an 67 I saw a lot of cute delta girls, anyways, I think you could keep it under that, just depends on the wood ya use and glass an resin that you put on. I wood build it as cheap as I could and maybe glass the seams outside and use it that way. just look at it as a throw away after a few yrs of use.

poling is very usefull in the marches. I would keep it as close to 15 as I could. build a model. I would rake the trans in at the bottom at about 4" and the front about 6" and lift the front up at 6".

JW

Permalink Reply by Ken Shindledecker on November 13, 2013 at 10:16am

First, thank you for your service, John!  I am a little younger, graduating high school in '74, so had the good fortune to miss that event.

Wood:  I was looking at some 6mm, 4x8' meranti,, but I don't really know what I'm looking for and am very open to suggestions/recommendations!

I had planned to glass the joints inside and out.  If using a 1/2" bottom, didn't know if I needed glass on the bottom, especially with this small of a boat,, or if I could just Coat-It?

Permalink Reply by John Weston on November 13, 2013 at 10:46am

I have never used that wood. I use MDO when I build a boat. most of my building deals with SoF kayaks. I would use 1/2 for bottom and 1/4 for sides. glass the seams on the outside and coat-it on the bottom. I would just use an oil base paint on the inside, I like a light gray color on inside. this is a work boat so don't get fancy.

will you be shooting from the boat? oh, oil base on outsides too, color your call.

JW

Permalink Reply by Ken Shindledecker on November 13, 2013 at 10:59am

Wow!.. I had never heard of MDO,, but then, I have so much to learn!!  For others following, here's a link to learn 'bout MDO plywood:  http://www.performancepanels.com/single.cfm?content=app_pp_atr_surt...

I "might" shoot from this boat, but it's mostly for getting to tiny "islands" and very small, diked ponds in the flooded fields.  I would stash the boat.  I need to see how stable this would be, first, before trying to actually hunt out of it.  If it were for hunting, I'd go to the sneak boat idea.  This should be a simple, light and safe, ferry.

Thank you for your direct/specific recommendations!  I need to hear that!!  Sounds like you really understand how I'll use this and you have the experience to help.

So, are you making fishing kayaks???  I've seen episodes on public t.v. of people fishing 'round the rocks on our Oregon shores.

Take care,   Ken

Permalink Reply by Ken Shindledecker on November 13, 2013 at 10:40am

Do you mean having 6" of rise in the narrow, bow end?

Oh,, I know there's a simple formula for scarf length.. Do you happen to know that, offhand?

Permalink Reply by Rick Newman on November 13, 2013 at 3:01pm

Ken,

8 to 1 or for more strength 12 to 1

Good luck on the project.

Rick N

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