Instruction manual

11
FIG. 16 - Taper On Masts & Spars
FIG. 17 - Shaping the Masts
FIG. 18 - Top of Lower Masts
3. Shaping the Spars
Main Boom & Two Gaffs: The boom and
gaffs also taper in a slight parabolic curve.
The maximum diameter of these spars
should be about one-thir
d from their fore
end, and then they should taper toward
each end. The forward end is slightly larg-
er in diameter than the aft end.
Bowsprit
: The bowsprit should be square
from the inboard end to about 1/8” out-
board, then it should change to a round
shape and taper forwar
d. It is best to start
with a square stick rather than a dowel.
On the inboard end, also cut the tenon
that fits between the winch bitts.
Finishing Spars
: When shaping and fit-
ting of each spar is completed, stain, var-
nish and set them aside to dry.
4. Main Boom & Gaff Assemblies
The main boom and two gaffs require that
jaws be added to their thr
oats for joining
to the masts. Plan sheet 3 illustrates how
to make the jaws.
Drill holes to represent the sheaves in the
main boom. Add the eyebolts, cleats and
chocks to all spars as shown on the plans.
5. Mounting the Mast
Assemblies & Bowsprit
After staining and varnishing the mast
assemblies and bowsprit, they can be
placed in the holes you drilled into the
hull. The bowsprit hole should be square
to fit the square end of the bowsprit. It is
suggested that you do not glue the masts
and bowsprit into the holes. The rigging
will hold them in position. Furthermor
e, if
the model gets restored in the future, the
masts can be easily r
emoved.
Check the alignment of the masts and
bowsprit. If not straight, looking aft, or at
the correct angle shown on the plans, you
can shim the holes. If necessary, drill the
holes lar
ger to accommodate shimming.
Center of a yard, heel of a mast, or maximum
diameter of a gaff or boom
Maximum
diameter
Straight line
This is the desired curve. Mathematically it is a parabola. It's
very close to the arc of a circle. Simply taper the spar gradu-
ally from maximum diameter to the end. For yards, make
sure both sides are the same.
Minimum
diameter
Taper
required
Dowel
MAST
Draw
square
on end
Kit dowel (if tapered)
Correct parabolic curve
YARD
1st cut 2nd cut Sanded
square 8 sided round
Square
Round
Tenon to fit
mastcap
casting