Paddleducks
Old Yahoo Group => Yahoo Messages => Topic started by: dragoncity on June 19, 2005, 03:48:14 AM
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Peter,
you can add as much FOAM, etc, as you like, you will NOT REDUCE the
displacement of the HULL by ONE gram !! All you have done is ADD the
weight of the foam.
Like many, you are confusing WEIGHT with VOLUME (displacemnet) of a hull.
All you can do is try to remove actual weight from your hull or superstructure.
( Like most of us, adding food, even so called 'lite' foods, adds weight !!! :-)
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Agreed Brett, but... the foam will increase buoyancy (i.e. lift the
hull/lower the waterline)...but placed on the underside of the hull
will in fact increase instability! Dai (Powell) here in Victoria has
a nice sidewheeler which sat a little too low in the water...the
sponson deck was just under the surface I recall...he "foamed and
fibreglassed the bottom" to lift the hull high enough so the sponsons
were clear and the wheels had correct immersion.
I have seen R/C model paddler plans deliberately drawing extra draft
so as to obtain correct immersion of the floats. Since it's all
below the water, nobody can really tell the diff..however, if a
paddler hull is carefully constructed with a clear idea of C of G,
topside weight, and wheel immersion, then you don't need to "cheat"
on the draft.
Remember, build the superstructure LIGHT with a low C of G..and you
won't need to increase buoyancy!
I always enjoy reading further thoughts especially from any PD's who
have had experience (good and bad) on this matter. This has probably
been the subject of more posts than anything else...and rightly so as
it's an essential part of achieving correct trim in smaller operating
model paddlers...one of the joys of static modeling where this is not
an issue!
PJ
Victoria, BC Canada