Re: [bolger] Hulls for lapstrake vs stitch and glue
- The moment of enlightenment for me came with a little sketch in the corner
of one of the Chebacco drawings. The table of offsets defines a smooth
hull. The inside of the lapstrakes are tangent to the outside of this shape
at their bottom edge. Their top edge, after beveling, is inside the defined
I laid out the strakes with Hulls and then added 3/4" to the top on the
plywood before cutting them out. I left an inch or so at the bottom edge
for error correction once they are hung on the molds. Tedious and maybe
overkill, but I don't have much faith in my "lining off" skills.
We'll know soon.
Roger (still spreading epoxy and fiberglass on the strake blanks and
sanding and sanding and sanding)
----- Original Message -----
From: "Bruce Hallman" <bruce@...>
> On 9/25/05, Rob Mouradian <r_mouradian@...> wrote:
>> To interject a question here, if you input data from a table of offsets,
>> do the
>> expansions assume that the panels wll just butt up against each other, as
>> would want for stitch and glue? If so, how do you account for the
>> over-lap of
>> lapstrake construction?
> For my Cartoon 5 experiment, I actually had the flat edge of
> each strake input as a surface. I didn't input all the data
> from the table of offsets, but rather mostly just dragged the
> lines around with a mouse. [using Hulls.exe]
> Spot checking for reasonableness against the table
> of offsets.
> I know it sounds tedious, but with practice is it quick. The
> Hulls.exe data entry for Cartoon 5 took less than three hours.
> In truth, I suspect that the thickness of the strake is
> inconsequential, as I used 1/8" luaun plywood.
> Also, as a though experiment, it has crossed my mind that the
> strakes could be laid out without thought to the strake
> overlap, and then the curvature could be adjusted by 'eye'.
> Imagine each strake with it's general 'banana' shape, you
> could compensate by increasing the depth of the 'banana'
> curve by one inch to allow for the increased curve caused
> by the overlap.