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Re: Full size drawings
By:Mark Kanzler
Date: 7/22/1998, 5:38 pm
In Response To: Re: Full size drawings (NPenney)

I keep hearing about the sensitivity of stitch and glue to panel errors. In Kulczycki's book he even suggests stacking left & right panels to drill stitching holes exactly symmetrical. There must be a way to reduce this risk of error. There are some good minds on this bbs. The best I can think of is using a strongback and forms and 1/2" stringers along the chines. The result is a skin on frame boat with a plywood skin. You lose some of what makes stitch and glue desireable in the first place though.

> I threw it away before I finished. Got as far as the preliminary
> stitching before I gave up. Had a pretty good idea it wasn't going
> to be workable just trying to cut it out.

> The program that CLC used to plot out the drawings used 5 stations
> as I recall, with three points between them. On a regular 8-1/2 by
> 11 piece of paper, that's fine looking. But when you stretch out a
> 13 foot drawing with that, you get straight sections that are about
> a foot long instead of curves. Even if one used the offset tables
> with one foot references you'd get straight lines 4" long. This
> just isn't a good way to make nice curves. Especially if you've got
> a gradual curve that only changes 1/8 an inch in several feet. You
> end up with anything but a nicely faired curve using straight line
> segments. Tighter turns are just plain hopeless, which is probably
> why CLC drew in the bow and stern curves by hand.

> The problem of line width is not inconsequental. A thick photocopied
> line that is about 1/8 inch thick isn't the best way to detail a curve
> that has offset table definitions as fine as 1/32 of an inch. Stay
> within the line all you want, you're still making a horrible looking
> edge.

> There is also the matter of keeping the paper perfectly aligned,
> without any shifting whatsoever along the full length of the plywood
> sheets. Something that is actually quite impossible to do with paper.
> The stuff stretches and shrinks quite nicely. Oh you can tape it all
> down, but you've no way of knowing if it's taped straight. Or if it
> was copied straight for that matter. Trying to run off a perfectly
> straight photocopy that is 13 feet long is an exercise in frustration
> at best. Sure those traction tires are of a perfectly matched diameter
> and have exactly the same slip.

> My boat, the Millcreek, uses a flat bilge panel. Which is extremely
> sensitive to variations side to side. Trying to make it match perfectly
> with all the above problems proved insurmountable.

> So I ended up with cut outs that instead of faired curves had
> lines like poorly laid concrete. Was the bilge panel straight? Dunno,
> didn't have a good way to measure it. Snapping a string along 12"
> just doesn't give precision to a 32nd of an inch.

> After all the work of trying to use full scale templates (and
> it's a *lot* of work, taking days to do), I trashed it, and redid
> it all with the offset tables, one batten and some pins. It took me
> just one afternoon. That time I got very nice curves, a near perfect
> bilge panel, and a beautifull boat that stitched together very nicely.
>

> I'll stand up and say full size drawings are a curse, while battens
> are a dream to use.

Messages In This Thread

I need graph paper
Matt Weist -- 7/21/1998, 4:06 pm
Re: I need graph paper
Mark Kanzler -- 7/21/1998, 6:36 pm
CAD for lofting
Karl Kulp -- 7/22/1998, 2:45 am
Re: CAD for lofting
Mark Kanzler -- 7/22/1998, 10:27 am
Re: CAD for lofting
Steve Austin -- 7/23/1998, 8:21 am
Re: CAD for lofting
Karl Kulp -- 7/24/1998, 6:33 pm
Re: CAD for lofting
Nick Schade -- 7/22/1998, 4:59 pm
Re: Full size drawings
NPenney -- 7/22/1998, 11:25 am
Re: Full size drawings
Mark Kanzler -- 7/22/1998, 11:38 am
Re: Full size drawings
NPenney -- 7/22/1998, 3:30 pm
Re: Full size drawings
Mark Kanzler -- 7/22/1998, 5:38 pm
Re: Full size drawings
npenney@erols.com -- 7/22/1998, 7:35 pm
Re: Full size drawings
Bram van der Sluys -- 7/23/1998, 10:40 pm
Re: Full size drawings
Mark Kanzler -- 7/24/1998, 5:46 pm
Re: Full size drawings
NPenney -- 7/24/1998, 7:14 am
Re: Full size drawings
Mark Carroll -- 7/23/1998, 5:40 pm
Re: Full size drawings
NPenney -- 7/24/1998, 6:40 am
Re: Full size drawings
Paul Lund -- 7/24/1998, 10:44 am
Re: I need graph paper
Mark Kanzler -- 7/21/1998, 4:52 pm
Re: I need graph paper
Mark Kanzler -- 7/21/1998, 4:31 pm
Re: I need graph paper
Mark Kanzler -- 7/21/1998, 4:37 pm