The orginal design has been around for years and years and still going
strong. There was two KR2S's in my hanger, one slighty ahead of the other.
One had the plywood skins on the 2 flat sides and the other didnt yet. When
it came time to join the 2 sides, the plywood creaked and fought very hard
to jump out of the jig. By looking at the plywood it seems to be under alot
of stress and on the virge of snapping.
My boat on the other hand does not have the plywood skins for that
reason. When I joined my two sides together they went with very little
force.
As for putting on the plywood, I have another kr2S side sheeted with
homedepot plywood which I will clamp over the side to sandwhich the plywood.
Others have used staples but the idea of putting tons of little holes in my
structure doesnt seem ideal.
Justin
----- Original Message -----
From: "Stephen Jacobs" <ask...@microlink.zm>
To: "'KRnet'" <kr...@mylist.net>
Sent: Tuesday, March 16, 2004 2:34 AM
Subject: KR>KR Boat Construction
> Good day all
>
> My mission today is all about avoiding the bow in the top stringer of
> the boat - especially when the fuselage is being substantially widened
> (and the wide section moved aft).
>
> a) I have noted the technique of deliberately building the sides with a
> known opposite bow - thus resulting in a straight top stringer after the
> sides are pulled into the boat shape. Sounds great but complicated for
> me as I would have to establish my own offset bow.
>
> b) Riley Collins pointed out that some KR's were constructed with
> vertical (or near vertical) sides, thus eliminating the problem. Is
> this a popular approach? It does not distract from the appearance -
> maybe increases the frontal area a bit - but certainly easier to build -
> Sounds like my style.
>
> c) I was impressed with the technique used by Eduardo in Argentina - he
> starts construction by building the top longerons into a horizontal
> crutch flat on the bench. The balance of the boat (lower fuselage) is
> then constructed (inverted) by adding formers and more stringers. The
> positive is that the formers can be rounded, giving a pleasing shape to
> the boat - also we have a nice straight datum line for all future
> measurements, incidence, thrust line, etc. He completes the boat using
> urethane foam fill between the woodwork with an epoxy /cloth skin inside
> and out - a meaningful cost reduction with no plywood, NO scarf joints.
> This would be the way for me, except that I am not convinced that this
> structure is equally strong - the only stringers that are continuous
> runs from the firewall to the stern post are the top stringers - all the
> others run in sections between the fuselage formers (presumably to keep
> the inside flush for glassing). I can see that an epoxy /glass skin is
> an acceptable alternative for the plywood skin, but what is carrying the
> load that would normally be transmitted by the two lower longerons on a
> standard KR boat? I would have preferred at least the keel to be
> continuous (and a bit wider).
>
> I initially thought that Eduardo had pioneered this technique (on a KR),
> but I have since seen pictures (97 or 98 KR gathering) that Dr. Dean
> Collette was using exactly the same approach. Is Dr Collet still
> around? - how far is this bird now? My interest here is to establish if
> anyone has run the numbers on this fuselage structure - is it OK?
>
> Steve
> Askies"at"microlink.zm
>
>
>
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