3017Re: Help with offsets
- Apr 30, 2011Thanks John K. I will build this boat. The more I look at it the more I likes it. You're right, I just need to slow down a bit. I have built several boats before but there was no lofting involved.
--- In AtkinBoats@yahoogroups.com, "John Kohnen" <jkohnen@...> wrote:
> I think John Atkin wrote at least once that one should _never_ scale
> critical dimensions off a plan, only take them from the full-size faired
> lofting. It's the Truth, whoever wrote it. On the Atkin plans the height
> of the bottom in the offset table is taken from the baseline, and the
> height of the sheer is taken from the waterline. Those heights are in the
> offset table, not on the profile drawing. The profile drawing will show
> the height of the waterline above the baseline and the spacing of the
> sections, and will have the dimensions you need to get the shape of the
> face of the stem right. If there are NO dimensions shown on the profile
> drawing maybe by mistake Mrs. Atkin sent you a copy of an early draft, not
> the finished drawing... But I'll bet there's everything you need in the
> plans, without having to use a scale rule. Just take it slow and easy and
> everything will begin to make sense as you move along. Start with lofting
> the profile, then the plan view, and finally the body plan, or sections.
> Don't forget to deduct the plank thickness when you make your molds.
> Alas, I can't find a good explanation of lofting on the Interweb. I
> suppose I should put an old article online myself one of these days...
> John A's story of lofting his Cabin Boy gives you an idea of what's
> involved in lofting an Atkin skiff:
> The best book I've seen on the subject is Allan Vaitses's, and if you feel
> totally lost maybe it'd be a good idea to sit back and wait for the book
> to be delivered:
> Lofting is unfamiliar to many amateur boatbuilders today, but it's really
> not that hard to learn, and not all that complicated for a simple skiff.
> You'll get there, Billy. Good luck!
> On Wed, 27 Apr 2011 20:42:08 -0700, Billy wrote:
> > Oh, specifically, there are no offsets from the bottom of the boat to
> > the sheerline to tell me the height of each station to make the molds,
> > there is nothing telling me the distance from the baseline to the load
> > waterline, there is no offset for the height of station 12, nothing
> > telling me how high the bottom of the stem is above the baseline, no
> > information at all about the heights of the transom from any of the few
> > given reference points and no information about station 0 which
> > intersects the stem at some point. Like I said there is a lot of
> > guesswork and scale rule work and figuring to be done to make these
> > workable plans. I guess my only viable option is to use the scale rule
> > and loft it as closely as I can and then fair the lines....
> John (jkohnen@...)
> I get up every morning determined both to change the world and
> to have one hell of a good time. Sometimes this makes planning
> the day difficult. (E.B. White)
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