SAILBOAT, 15' X 5', 400 POUNDS EMPTY
This is Jewelbox Junior, a 15' version
of the original 19' Jewelbox built a while back by Karl
James in Texas. That Jewelbox went all over the US and parts
of Canada and I understand was sold a few years ago to someone
in Florida and replaced by a larger sharpie that Karl had
designed. Here is a photo of the original Jewelbox.
JB Jr is also narrower than the original
boat, the bottom now planked with just two sheets of 1/2"
plywood. Perhaps a good comparison of the two boats would
be that Jewelbox needs 16 sheets of plywood and JB Jr needs
9. In particular I hope that JB Jr could be towed behind
a small car. Two protoypes of JB Jr were completed last
fall. One by Vern Stevens in Idaho and the other by Erwin
Roux in Pennsylvania. Vern had a chance to take this photo
before winter hit:
And Erwin sent quite a
few great photos taken on a beautiful autumn day.
Here you see that JB Jr has that Birdwatcher
cabin. The idea behind the Birdwatcher cabin, invented by
Phil Bolger in his Birdwatcher design, is that the crew
sits low inside the cabin looking out through watertight
The crew weight thus acts
like ballast. The boat becomes more stable with extra crew
where a normal raised deck boat becomes less stable. I did
some paper studies of the self-righting abilities of Junior.
With it lighter bottom planking, Junior is bound to be less
in that department than Jewelbox, which Karl says has righted
from having its windows submerged. By my studies Junior
should self right from up to 65 degrees of roll. Beyond
that and she would roll another 15 degrees and become stable
on her side. She won't flood due to her Birdwatcher cabin.
If you couldn't rock the boat back upright you would have
to exit, right the boat from the water by stepping on the
leeboard, and climb back in. And you would need a reliable
step to do that in any high sided boat. These are just paper
studies. I would expect my IMB design to behave the same
way. Larger heavier designs, like Jewelbox and Scram, should
self-right from a full knockdown. More weight on the bottom,
especially another layer of plywood there, would be a good
investment if you could tow the extra weight.
I've shown Junior with a sharpie sprit
rig, although you could substitute a lug sail as Stevens
Simple nail and glue construction with
no jigs or lofting.