Generating stich and glue panel templates

[small cat]

Don't know if this is a silly question but here goes.

Can you generate full scale hull panels for a stich and glue skiff etc. like this:

Draw a plan (to scale)
build a frame
temporarily attach sheeting
trace the panels
remove sheeting
lay panels flat
smooth out the curves
scan
increase panel size by required scale factor

Then go build a boat?


Any input would be greatly appreciated

[jehardiman]

Before you build the frame, you need to determine if the surface is developable. Not all "simple" shapes are developable from sheet goods.

[PAR]

That could work, but there would be a problem. In the sizes you'd need to scan, the thickness of a pencil lead would amount to an inch in a 15' day boat and a foot in a sizable yacht, which precludes the whole point of trying to make accurate panels layouts. There are a number of panel layout software offerings from a few manufactures. You may well be best advised to use one.

You could setup your station molds full size, then using oversize stock, trace the panel shapes, but there would be more waste, though the accuracy would be quite good. This is assuming conical or other developable forms are used.

[small cat]

" the thickness of a pencil lead would amount to an inch in a 15' day boat"

I recognize accuracy would be an issue in terms of truly reproducing a full scale version of the original model, but I'd simply be trying to get close to the look of the original model.

Perhaps the sequence would be more like this:

Draw a plan (to scale)
build a frame
temporarily attach sheeting
trace the panels
remove sheeting
lay panels flat
smooth out the curves
scan
cut scanned panels .... build new model and see if I like the look
increase panel size by required scale factor
build boat


If that won't work then can someone make recommendations for mac based panel layout software

[Rod Tait]

Try Carslon Designs free shareware at http://www.carlsondesign.com/#Professional_Shareware

[Raggi_Thor]

You can also try a demo version of Rhino. The demo version allows you to save 25 times...

[byankee]

didn't John Gardner develop plywood panel projections from half models? It seems to me that your method is basically the same as the half model route. I would do as you suggest and build an intermediate larger scale model to double check and refine you panels before cutting the full size sheets though....

Although it's not Mac compatible (well it is if you have a DOS or windows emulator installed on your Mac), the sofatware Plyboats is cheap and easy to use and it will generate panels. I've been playing with the demo and it seems pretty cool. See http://www.plyboats.com/

[PAR]

Nat Herreshoff had a self designed machine to pick up points on his half models. This machine was quite accurate, but the offsets generated from these, received substantial correction on the loft floor, where a corrected set of offsets was created (when necessary). Small scaling factors will work, but large scaling ratios will not very well. How big will your real boat be? What scale are you thinking about using on your first and second generation models? PlyBoats, HullForm, Carlson's products, Rhino and several other software packages will do this for you, without carving a model (you actually do, but it's virtual) These panel layouts can be directly printed, plotted or converted to CNC for machine cutting of the pieces. A lot of the software available has a free demo version for download.

[small cat]

I'm trying to be pretty practical about this project ie: think small! the finished boat won't be more than 13' long. The initial model and more importantly the flattened panels wouldn't exceed 13" (they have to fit on the scanner bed) The large model could then be built 1/4 scale ... jut over 3 feet.

But I did run accross this page and it looks right up my street!

http://www.angelfire.com/ego/lewisboatworks/html/fishdes_a.htm

[byankee]

plans for small stitch and glue skiffs are pretty common and all of the panel projections have already been done and tested. Here are a couple of stock designs that might work for you (and the plans don't cost too much!)

http://www.bateau.com/proddetail.php?prod=FL12&cat=9

http://www.bateau.com/proddetail.php?prod=FL14&cat=11

http://www.glen-l.com/designs/outboard/powerskiff.html

http://www.cmdboats.com/powerskiff14.htm?cart_id=c880a9daa7ec55184e15394c9c65b7ed

and there are many many more out there....

of course, I understand the desire to design and build your own boat. In any case, these plans may serves as inspritation if nothing else.