The Gougeon Brothers on Boat Construction - WEST SYSTEM Epoxy

200 First Production Steps
<strong>The</strong> Centering Cable
Before setting up the frames and jigging, run a cable the
length of the boat to represent a centerline. This will be
the reference for aligning frames and measuring station
lines. If you are building a large boat and can borrow or
rent a transit, consider using it to make sure that your
cable is accurately laid.
A string will work for a centerline, but we prefer to
use 1 ⁄16" or 3 ⁄32" (1.5mm or 2mm) diameter wire rope
stretched to about 500-pounds (230kg) tension. <strong>The</strong>
cable stays taut and will not break or stretch if you trip
on it. If your foundation is the floor, run the centering
cable an inch (25mm) or less above it. If you are using
a strongback, run it above the cross pieces. Anchor the
centerline on guides outside bow and stern of the boat.
For longer hulls you may want to add slotted support
blocks at intervals along the length of the cable. Both
guides and blocks should be indestructible. Set them
so that even the clumsiest feet can’t move them after
you’ve begun setting up.
<strong>The</strong> centerline must be level so frames can be set up
perpendicular to it. Use a line level, available at a
Centerline cable
2" � 12" sides
Measure out from the centerline
to square the stations marked
on side pieces.
Figure 18-2 A strongback arrangement for a dirt floor.
hardware store, to check it before finally fastening it.
Hang the level in the middle of the cable and raise or
lower one end of the cable until it is level. Turn the
level 180° to check in the other direction. If it’s level,
you’re done.
When the cable is centered, put down the lines over
which to erect frames. Mold frames are usually positioned
on station lines, spaced as they are in the lofting grid. If
you are including permanent frames such as bulkheads
in the set-up, draw lines to position them.
Space the lines over which the frames are to be set up
exactly as they are on the lofting floor. You can use the
big lofting square to establish the lines perpendicular to
the centerline. Line the square up with the centerline at
each mold frame or permanent frame position and
mark the floor or timbers on each side. If you are not
using a strongback, draw the lines directly on the floor.
If you have a strongback, draw lines on it to represent
the station lines. <strong>The</strong>se may not be at perfect right angles
to the timbers if the timbers are not parallel or if they
are warped, but they must be parallel to each other,
spaced from each other just as they are in the lofting,
and perpendicular to the centerline.
2" � 4" stakes
through bolted
Station marks
for mold frames