On Sat, 25 Sep 2010 12:58:15 -0700 (PDT), Frogwatch
wrote:

MiniCup #`1 is still sitting on sawhorses while I decide whether or
not to rebuild her. #2 which I have been using developed cracks from
rot in the 3/16" poor quality ply I used on her even though she had
been glassed with 4 oz glass and epoxy. While fixing this I found
more rot so ended up covering her entire rear with another layer of
glass. Am almost done. However, she seems to have absorbed some
water that I cannot get rid of as she seems heavy even with ports cut
in all her spaces.
Am looking over the old MiniCup plans and considering how to design a
modern version that will be much lighter. Considering using 3mm
Okuome Ply covered with 8 oz glass all over with stiffening ribs of
foam and glass. All interior joints would be glass taped and interior
epoxied as well to seal the wood. Transom would be reinforced with
thicker ply and G10 glass composite for the rudder stresses. Cockpit
and mast step would be self bailing and all hardware of either bronze
or SS. Instead of being a "hardware store boat", I'd specify buying
actual boatbuilding screws and pulleys made for boats. I'd reccomend
buying 1/8" Al tubing for the mast and 1/16" for the two other spars.
The sail should be sewn from white polytarp, none of this duct tape
stuff and visqueen. I have devised a much improved gooseneck where
the two spars attach to the mast. Any other ideas?

If this sail boat isn't going to be dragged up on the beach and then
jumped in but is always going to be afloat when supporting a load I
don't see a thing wrong with your plans.

I currently build dinghys about the size of a Mini Cup out of 3 mm ply
sides and bottom. The transom would be 8 mm ply with a doubled where
the engine mount is and a honeycomb seat top bracing it on the inside.
Designed for a 3 HP motor. I do add a 3 mm doubler in the area where
the oar locks are mounted as I am afraid of the sides flexing if
someone puts long oars in it.

I cover the entire outside with the lightest cloth I can locate -
probably about 4 oz. cloth in your numbers. The inside bottom is also
covered, more for a wearing surface.

All joints are faired and taped, as the boats are stitch and glue.

My boats have a small bow seat, more as a structural member then a
seat and a stern seat. Both are topped with honeycomb that I make my
self with 3mm ply skins and core. the center thwart is the same thing,
i.e.. skins and core.

I used to build essentially the same design with 1/4 inch ply but it
was really too heavy for one man to handle without davets, thus the
change to 3 mm.



Cheers,

Bruce
(bruceinbangkokatgmaildotcom)