new member, boats, computer

**RockyShore** · #1 10-29-2012, 08:46 PM

Hello All,

New member here from Colorado. My interest is paper feasibility models of new hard-chine boat designs that I'm working on. Found the site looking for help on the modeling.

Currently I've done 1:10 models of a 2.4-m rowing dinghy based on hand-drawn plans transferred to QCad software to print out the strongback frames. Panels are cut and try. The paper models showed that the rather extreme twist in one panel is feasible. They also led me to abandon a box-beam central structure and substitute a (paper) I-beam spine as the structural basis.

I'm using Linux and the Python programming language to fit a 3rd-order polynomial to my eyeball curves to smooth them for the next iteration of the model. That works. Now I'm trying to write a Python program to fit triangular finite elements to the panels with the new curves to develop them onto a flat surface with enough fidelity that they will determine the shape of the hull. I'm following the lead of Jim Michalak, but he uses a spreadsheet and the details are obscured. My program doesn't work yet.

Some members may advise FreeShip!, Rhino, and other packages, but I don't like the non-uniform rational B-spline approach because it can give localized small-radius curvature. I also like the challenge of thorough understanding by doing it myself. I'll keep looking here for ideas, help, and inspiration.

RockyShore

**Vermin_King** · #2 10-29-2012, 08:52 PM

Okay, I think I will go grab a box of crayons now ...

Hard to believe I used to be an engineer.

Welcome

**josh** · #3 10-29-2012, 11:46 PM

Was that English?

**josh** · #4 10-29-2012, 11:47 PM

I didn't understand a single bit of that, but welcome!

**Retired_for_now** · #5 10-30-2012, 07:20 PM

Welcome aboard! You found the right place if you're looking for a quick and cheap way to model boats formed from flats and conics (plywood ... Bolger anyone?). The trick is, as always, scaling the material properties (flex, strength, stiffness) but card stock in various thickness or laminations should certainly allow you to prove if a design is buildable from sheet stock.
Yogi

**ashevilleangler** · #6 10-30-2012, 07:35 PM

Rocky, Have you discovered this site?

Duckworks Magazine

Lots of designers post there on their methods and Jim Michalak's Newsletter is also hosted there. You could spend many hours going through older posts and learning a lot.

Hope this helps,

Curt

**looker** · #7 10-30-2012, 09:01 PM

"Hull Designer" by Carlson Design seems to do what you are attempting. I certainly suggest you take a look at it. Hulls