scale model or half model materials

Charlie S and Titan

Charlie S and Titan

Well-known member
Hi All,

Thought I'd whip out a scale model of the boat first as an experiment in thinking the construction through. Plus my daughter is very interested in all the ciphering and drawing on graph paper so, I think this would get her even more excited about the "project". She likes to help on projects.

For those of you that have built a model or half model of your boat before building it, what did you use for materials?

Looks like Sam Devlin uses thin plywood. Would balsa work? I saw that the local five and dime had balsa in the kids section.

Is superglue the best bet for adhesive?

Thanks,
Charlie

[inline drawing.jpg]

drawing.JPG
 
Wait a second... just occurred to me...

I could just resaw some scrap pine into really thin on the bandsaw and use that.

Let me try that and report back.

Charlie
 
I think you are looking at the original BBSB with all those compound curves, right?

If you are you will want to experiment with the grain direction on the pine you are resawing. Even thin the pine will still want to behave like a 2x4 and twist where you don't want it to.

The balsa will bend better, and maybe some poplar would work better when resawn.

I have only made one model boat and used poster board since it was a plywood design.
 
Hi Ray,

Thanks.

Yes, it is a traditional planked barnegat.

The frames won't need to twist like planking. The "real" frames are 1 1/4" thickness so at 1/16"=1" scale I think I need .2815 thickness - for this purpose I'm rounding my model to a quarter inch.

The 1/2" planks on the other hand would only be 1/32" and there is no way I'm gong to cut anything that thin. Maybe I'll use some thin cardboard cut into 3/16" strips for my "planks".

I was hoping it would be something more durable that I could put on the shelf in my office.

I just tried bandsawing some scrap pine down to 1/4" and it didn't work too well. Too much wandering of the blade. I think the idea could work if I had the right blade on it. I have a 1/4" blade on there now and can't find my other blades anywhere (shop is a mess). I either need to find my other blades or pick up a new one.

Hmm, what is plan B...

Back to the drawing board.

Charlie
 
Actually, I'm going to skip the model. I don't really *need* it for anything, I'm just going to go back to working on the full size rib/frame drawings. It is a more productive use of time.

Charlie
 
Charlie Do you have a table saw? If you do you can cut thin strips on it. A band saw, not as easy.
 
About the modal, good idea. Make it larger 1/4 scale. You do not have to finish the modal but work out details on the framing. Could save you money in the long run. If it doesn't work out in the modal it won't work out in the full size.
 
Go down to the hobby store they have these thin strips of balsa, something like 1/32. Not expensive, you cut it with an exacto knife, use it lie model plywood.


Ed.
 
Charlie:
Half models are made with 1" boards screwed together, this was a perfect scale for lofting. Each layer could be removed to trace the lofting lines onto the graph paper. I'm sure Cedar and Pine were popular woods to work with.

Good luck!
 
Charlie,terry is right.The stacked boards then carved to shape would enable the builder take off the lines to full scale from whatever scale was handy for him to use.
I got this half model of a 14' Cape Cod Catboat,from an old timer about forty years ago.He carved out of pine and mahogany (below the water line).1" scale to the foot.

P1000232.JPG
 
A problem I see with the carved method of making a half-hull model is you never find out whether or not you can actually build the boat with plywood. You can't build any shape you want out of plywood. For instance, you probably couldn't build a sphere out of plywood. Devlin has a good section on building models in his book. The method he uses is to cut 4 shapes out of plywood: The chine, the sheer, and the bow and stern transoms. These are glued onto the board which defines the center line of the boat (the back of the half hull), and then the model plywood is used to cover the space between the keel and chine, and the chine and sheer. Later you can trace out the lines of the panels onto mylar film. This way you will find out for a few dollars and a couple of hours of your time whether or not it's even possible to build the boat out of plywood, and if it's not you'll be able to see why and what you need to do to alter the shape of the boat so you can build it. The book is worth buying just for this section on making models. Exactly how this is done is fairly technical.

Check out my half hull model for the Peregrine.

Ed.
 
Thanks all.

Fortunately I do not NEED to do this, since Mr. Perry did the hard work of full size lofting and writing up offsets for the frames. This saves a HUMONGOUS amount of work. I was more thining of doing it to generate some excitement for the project, test out some of the construction on a small scale, and have a tabletop model to look at when I am busy and can't get to working on the real thing. Looks like it will be more effort than I initally thought, and since I don't need it to loft panels, it is sort of unnecessary work.

Ed, I read in a boat building book (Chapelle?) about the solid half models, the would carve them, pull the side and top measurements from the model, then slice them up into sections where each station would be, that way they could get the measurements direct off the model. I don't think they were worried about plywood, so I can see how a model like Ed made makes more sense for plywood construction.

I tried some of the advice this morning. I started with a 3/4" pine board, cut two slots in it leaving a 3/16ths web, cut it off with the bandsaw, then planed the web off. Similar to the technique John shared for making planks.

This left me with my 1/4" stock. From there I overlayed the graph paper with the frame, pricked through it to transfer the lines, used a pencil to trace the line, back to the bandsaw, cut out the line, then set my fence for 1/4" and cut the inside line.

Doing this I ended up with a miniature frame section (bottom part of frame 5). Sort of like doing a sawn frame, but in miniature.

Charlie
100_4525.jpg
100_4531.jpg
100_4533.jpg
100_4534.jpg
100_4535.jpg
 
Last edited:
a model is when you want to determine the shape and number of the planks. Do you need stealers etc. You can probably do this on the frames when you have everything on the strongback but a model may make it easier to determine the width required for the planking stock. Unless you have this info already in which case I would start by lofting everything out on a couple of thin sheets of plywood and get some full size patterns going. Course I would be in such a hurry to do this that I would probably forget a station and wonder why my boat is so short. :^)

Have fun with this boat and keep your joinery tight.

Eric
 
You must log in or register to reply here.
Back
Top