Dingy Stretching

can one increase existing measurements say by 10% or 200mm to make a dingy bigger?

Or how do i do it - say length of 2.2 stretch to 2.8 and width of 1.1m to 1.4m ???

Thanks for the input

 

The simple alteration is length,all you have to do is increase the station spacing a bit to achieve the length you are aiming for.You can use existing station moulds.Normally a 10% scale factor is not a huge variation but more may not be wise.To make the dinghy wider as well is a bit more difficult as you need to make new station moulds or use a 3D CAD program that will allow for differing scale factors in all 3 directions and then you need to offset the resulting shape by the plank thickness to determine the shape of the new station moulds,at the locations where the new length would locate them.For a dinghy that is known to work,there is a fair chance of a useful boat but for anything larger it ought to be run through the usual calculations to check for nasty surprises and to establish the location of the revised waterline.

 

Thank you for the help.
Much apreciated

 

You have proposed changing length from 2.2 to 2.8 which is more than 10% in fact that is 27% Changing the width from 1.1 to 1.4 is much more than 10%. It may not be advisable to change both dimensions by that much.

When you mention the width dimension, are you measuring the width of the bottom or the width of the gunwales (sheer width at the widest point) ? Typical dimensions for the bottom width of a ( nine foot) 2.8 meter dinghy might be somewhere from (36 to 45 inches) or 0.9 to 1,14 m. The 1.14 bottom width would make the dink have more initial stability but it would also make it more difficult to row or paddle. The more narrow bottom would be less stable but still entirely usable. It would be a little more tender but not dangerously so for a reasonable user.

Please tell us how you intend to use the little boat. We will then be able to give you more detailed advice. Post a picture or a section drawing if you can. Also tell us the probable weight of the users and the weight of the gear that you will also carry. Is this to be a row or sailing boat or a power boat? If you want it to be a fast power boat, the whole set of numbers will need to be considered.

 

For lengthening the stations can be reused, except that the first and last may need to be re-faired.

 

Im greatful for all the help but your'e right it's become complicated.
All i want is to build a simple dingy/annexe of 2.8m x 1.2 - 1.4m wide.
It's just to cart provisions to and from my Pahi 42.
Any free plans out there?

 

You might find something suitable among these:

Absolutely Free Boat Plans http://absolutelyfreeplans.com/boat.html
A 10 1/2 ft Skiff | Free Boat Plans http://hvartial.kapsi.fi/skiff/skiff.htm
Free boat plans https://intheboatshed.net/free-boat-plans-at-intheboatshednet/

 

This is Duckworks free plans.
Plans & Kits - Free Plans - Page 1 - Duckworks Boat Builders Supply https://duckworks.com/free-plans/

This clever chap doesn't have plans but shows how to maximise efficient use of plywood in hulls he has designed as well as providing basic drawings of his boats.
FLO-MOFlowing Motion https://flo-mo.weebly.com

 

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Thank you - will have a look.