24 PROFESSIONAL BOATBUILDERREFIT: Rybovich Rebuildslaminate layers. Bandy cold-molded
four layers of 6mm- and two of 9mm-
okoume plywood into the tunnel.
On Butterball Bingham had started
the cold-molded bottom in diagonalIn Rhino he was also able to recal-
culate the hull buoyancy, as the tunnel
actually reduced the displacement and
thus changed the trim and waterline.
Placements of the engine and tanks
were adjusted to trim the boat based
on her altered buoyancy.
With the tunnel design worked out,
Bandy attacked the bottom, cold-
molding two layers of^3 ⁄ 8 "-okoume ply-
wood with a layer of Saertex 17-oz bi-
axial berglass between them. He glued
the inner layer of wood to the frames
with WEST System Six10 thickened-
epoxy adhesive. (He shot many of
these premixed cartridges in the two
rebuilds.) e glass and second layer
of the okoume were wet out with
MarPro low-blush laminating epoxy.
e layers were temporarily screwed
to the frames that de ne the concave
bottom form while the epoxy cured.
The tight radius of the tunnel
required application of more thinengineer, he follows very much in the
tradition of the Rybovich yard, where
calling on actual shing experience
and building only slight changes in
form or materials keep any one build
from going astray. While the tunnel
was new to the Rybovich hull, for years
Bandy had been running boats with
tunnels, including a Bandy 35 (10.7m)
sport sherman of his own design and
construction. He said he based the
alterations of the Rybovich on his
experience with the 35, and some les-
sons from operating his Jarrett Bay 53,
which had su ered from loud pulsing
and chronic paint damage on the bot-
tom. “When I cut the wheels down,
the noise just disappeared,” Bandy
said. “Now I believe in tip clearance.”
For the Rybovich, he has a 28"
(71mm) four-bladed propeller. With
the 2.48:1 reduction gear and 3,100-
rpm motor, he estimates tip speeds to
be 12' (3.7m) per second.RybovichRefit170-AdFINAL.indd 24 10/31/17 2:25 PM