[Rhodes22-list] Sail Plan Changes

[Brad Haslett]

Hank,

Basically the change would be from a P measurement of 34 to slightly over 33
with the other parameters - I of 40, J of 13, and E of 12 remaining
unchanged.  I'm hoping someone can put a slide rule to that and give me a
ballpark effect in simple terms like (1) you won't notice the difference, or
(2) you're a genius backyard engineer, or (3)  you're an idiot, what are you
thinking?

Brad

On 10/31/07, Hank <hnw555 at gmail.com> wrote:
>
> Brad,
>
> Consider the sail as the force at the end of a lever.  The closer the
> force
> to the fulcrum the less the effect.  So, the higher up the sail, the more
> the boat will heel over in a blow.  Lower sail, less heeling.  Also, the
> rhodes sails faster upright than heeled over.  This is not true for most
> sailboats.  Many boats increase waterline length, and theoretical hull
> speed, when heeled over.  The rhodes hull shape really doesn't so heeled
> is
> not better.
>
> Hank
>
>
> On 10/31/07, Brad Haslett <flybrad at gmail.com> wrote:
> >
> > Ok, boys and girls, put your thinking caps on!  Here's the deal, the
> sails
> > rep I've been visiting with has a 9.2C just like mine that he raised the
> > boom 10 inches on for better headroom (mine is about 5' 11 1/8 inches
> > above
> > the cockpit which gives me 1/4 inch to play with versus getting whacked
> > while standing up).  He also shortened his boom length 21 inches which I
> > really don't want to do.  He says the boat handles better, has less
> > weather
> > helm, and the center of effort moves forward.  Other than the obvious
> loss
> > of sail area (less than 5% by my calculations) what can be anticipated
> in
> > changes of handling characteristics? He (the rep) says it moves the
> center
> > of effort forward and the boat is more stable based on his experience.
> >
> > Now this from Stan's site: *Lowering the boom, automatically lowers the
> > sail
> > inside the mast, which in turn lowers the center of effort of the sail,
> > therefore increasing the stability of the boat without cutting sail
> area.
> > In fact, boat speed actually increases slightly by lowering the boom.
> >
> > *Can we assume then that raising the boom will decrease stability and if
> > so
> > by what margin?  What is your experience? Loss of speed is not an issue
> > with
> > me. Everytime I think about these things I get a headache.  I'm sure
> Stan
> > could answer this in about 2 seconds but I'm afraid he'd want a donation
> > for
> > his experience.  That greed thing again.  I'm hoping someone can think
> > this
> > through and give an informed opinion at a reasonable cost.  Like free!
> >
> > Brad
> > *
> >
> > *
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> >
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