nutshell pram

hope this is the right place for this,
but i am about to purchase the plans fpor one of the nutshell prams by JoelWhite, but really want to builsd a boat about 8'.6" long, this falls in right between his two plans, at 9'6" and 7'7", can the smaller one be stretched that much- or will it end up being too shy in the beam.
thanks

 

Dont sweat beam dimensions. You want to stretch the lovely little boat by about 12 %. That is pushing the limit for modificaations but, in this case, it will probably work out just fine.

Use the design dimensions for the station molds and Increase the station spacing by 12 percent or so and go for it. The resulting boat will float just a tad higher than the Nutshell when an equivalent design load is involved.

If you are to use ply for the planking, the extra length will mean that you need to scarf some of the planks. That will cost an extra sheet of ply and some careful scarfing work. If that does not deter you, then stretching Nutshell a little wil probably produce a very satisfactory little dink.....or maybe better.

 

Stretched Nutshell pram... Swear to (pick a deity)

 

thanks guys, i will get into that, the extra work will be great!!

 

The planks will have different shapes after stretching. If the plans have shapes for the planks you can not simply stretch them.

 

The plans that I saw for the 7'7" boat were $195.00.
That's high $$$ for a small dinghy. I assume the price is justified by the amount of detail in the plans. For example there may be full size templates for each of the strakes, or at least detailed measurements for those strakes.

Most of that will not translate as easily as just re-spacing the frames. In traditional boatbuilding this would be accomplished by lofting, something most first time builders are not excited about. Proper lofting would require a table of offsets which might be included, or might not if there were full size templates.

It is certainly possible to just set up the stations, re-spaced, on a strongback and line off the strakes the old fashioned way. I doubt instruction on how to do that would be included in the plans. It isn't rocket science, but it somewhat defeats the purpose of relatively pricey, highly detailed plans if all you end up using is the station dimensions.

I'm not trying to be negative, just realistic. It's a very pretty boat.

Added:
I found a different source for those plans @ $75.00. More in line with other dinghy plans. Full size mold patterns are included.

 

My remarks were predicated on the builders ability to line off his planks in a satisfactory manner. As mentioned above, this is not rocket science. And yes of course the location of the particular dimensions of individual planks will not be the same.

The Nutshell and every other planset offered by Wooden Boat are regularly overpriced. The Nutshell price at $195 is a bit much for a relatively simple pram. But if they can get away with it.....so be it. I actually admire them for their superior marketing skills. There are a lot of other sources for nifty little prams that cost almost nothing. Some of John Grdners books for example.

I do wish the OP well in his build. Never mind the cost of the plans. Nutshell is precious but so are some of the Hereshoff prams that appear in magazines for free. Just not with the building details and instructions that I presume/hope that White and WB have provided. First time builders will be ahead of the game if a good set of building instructions are provided even if the plan set is priced higher than the norm.

 

ok. i am not against doing the"planking" from scratch.- spiling.
but if there were other plans of a similarily pretty lapstrake pram, but in the 8'6" size range.
any ideas.
i do have one of gardners books, "building classic small craft" with lots of detail in there - but no prams in that size range.
but did find this http://www.brooksboatsdesigns.com/Compass Harbor pram main/CompassHarborprammain.html
what do you guys think.

 

The Compass Harbor Pram looks nice, and just about the length you want. If it absolutely had to be 8'6" you could change the rake of the bow transom and get very close to that dimension.

 

I know this is nowhere close to what you're looking for, but it's on the same site.
What a beauty. http://www.brooksboatsdesigns.com/BrooksBoatsDesignsplans/Peregrine/peregrine.html

That would be great fun to row.
When I lived aboard I had a Gloucester Light Dory that I built very lightly... stitch & Glue with 1/4" ply. I'd often row 2 or 3 miles in her just because it was fun. Equipped with proper oars those long lean boats are wonderful.

 

yup , you are right- nice boats on his site.
those 2 inches shouldnt matter too much- but i do hear you- thanks.
the 8 1/2 will match the beam of my sail boat better, when it is on the davit's.
that is my real concern.
thanks all

 

If you don't mind round bilge, Watercraft magazine no. 101 (current issue) has a Paul Gartside tender article with lines and offsets. 8ft 6ins long. Can be built strip plank.

 

The shape of the planks for a stretched dinghy are easy to do. When I made my dinghy based on Sam Devlin's guppy design. Sam told me to just stretch out the spacing equally and everything would line up. And it did. If you want to private message me I can give you more details on how I did the stretching.