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 tungsten on November 7, 2013 at 7:53am

yes 48",the little braces or bulworks(sp) I think there called are not needed.I float tested my boat with nothing but the gunnels and it was no problem at all.I think having both sides of the sides glassed helped.

Careful watching those red barn videos they'll drive you nuts!! LOL I watched them all winter one year.I finally just went and bought some cheap Baltic birch plywood and started building.I haven't watched a video since.

here was my first boat,

 

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Permalink Reply by Ken Shindledecker on November 7, 2013 at 8:09am

Gorgeous!  I think that's what I'll have to do... just get some cheap stuff and perhaps even build a half model.

Man,, the interior of that second pic looks like a bathtub!... in a good way...  I could imagine such a thing, made into a bathtub, in a hunting/fishing lodge.

Here are two designs to compare... Dave Z's Drifter and a Buffalo Boat.  I think Dave's lines are more what I'm looking for, with perhaps your idea of the parallel/flat spot.

http://www.riverstouch.com/BobAfloat1.JPG

http://montana-riverboats.com/fragments/Driftboats/Buffalo-Boat/fir...

Permalink Reply by Ken Shindledecker on November 7, 2013 at 9:54am

So.... should I just consider building two boats... a flatter pole/jon boat for ducks and a small pram for river use???... or just be happy with a compromise boat?

Tungsten:  How many # would you put in your boat?

Permalink Reply by Andrew on November 7, 2013 at 11:07am

I've floated with Tungsten in this boat, and neither he or I are small guys, I'm 300+ lbs, so with the motor & him your easily 500+lbs capacity. 

His is a lovely little boat.  If you don't look behind you, you would think your in a 15' boat.  There is so much room in that front seat it is amazing.  


Andrew

Permalink Reply by Ken Shindledecker on November 7, 2013 at 12:56pm

Thanks, Andrew!  Yep,, that's a whole lot more capacity than I need for me ~220#, my dog 85-90#, and 75-100# gear, max.

Permalink Reply by tungsten on November 7, 2013 at 2:46pm

Ya I never thought about that Andrew,my guess is we were 650+ with the beer,battery and motor.

Permalink Reply by Ken Shindledecker on November 7, 2013 at 3:15pm

Ya,, and as the beer is consumed, the boat lightens and rises,, along with the river level.  ;-)

Permalink Reply by Dave Z on November 7, 2013 at 10:35am

Ken, is that red rapid robert built off of those plans?  I might need one of those too...

 

 

 

 

Permalink Reply by Ken Shindledecker on November 7, 2013 at 10:58am

Thanks, Dave!!

Here's a Rapid Robert under way:  http://www.google.com/url?sa=i&source=images&cd=&cad=rj...

Vintage pic and excerpt from Roger Fletcher's Book:  http://books.google.com/books?id=_AQc_9Agj6QC&pg=PA21&lpg=P...

And Roger's Book at Amazon:  http://www.amazon.com/Drift-Boats-River-Dories-Construction/dp/0811...

This book has a number of plans in it.

Permalink Reply by Ken Shindledecker on November 7, 2013 at 12:57pm

Yes, the red boat is a Rapid Robert and the links are in my message above.

Permalink Reply by tungsten on November 7, 2013 at 2:53pm

Ken I'm not sure a flat spot would be needed in a short 8' or less ish bottom,not dead flat anyway.Your first pic of your model shows it about right I think.You could flatten it a little but keep a gentle bend ,this will help keep the sides fair when you stitch.I think my floor was 9'8" ish long.

Permalink Reply by Ken Shindledecker on November 7, 2013 at 3:30pm

I know it's not a simple matter of direct comparison, but 9'8":12' =~80%; 8':10'=80%.

I'll see if I can maybe raise the transoms, just at the ends, so as to keep a longer waterline,, but if I lose all rocker, then that wouldn't be good in a small wave.

I'll play with smaller designs with index cards stock, just to see what happens when I change the shape of the sides, or the bottom a bit.

And, I want to think more 'bout overall bottom shape.  Here's a nice little piece I found long ago, on kayak design and the concept of Swede form v. Fish form/Cod's head.

Thanks again!

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