The Gougeon Brothers on Boat Construction - WEST SYSTEM Epoxy

176 First Production Steps
stem or fairing line, and this intersection needs to be
transferred to the half breadth view. Place your square
perpendicular to the baseline on the point where the
load waterline intersects the stem. Project this point
down to the half breadth centerline. This will give you
the end point for the waterline in the half breadth view.
Go back to the body plan and measure the width of the
stem at this point and transfer it back to the half
breadth plan.
<strong>The</strong>n you are ready to fair the load waterline in the
half breadth plan, following the procedures discussed
earlier. Move the batten the minimal amount off the
points until the curve looks fair and then draw in the
line using light pencil. <strong>The</strong>n remove the batten and
make a quick survey to see at which stations you had to
move it from the marks in order to fair it. Use a clean
pick-up stick to transfer these corrected load waterline
widths to the appropriate station sections in the body
plan. You now need to redraw the station sections in
the body plan to conform to the new waterline widths.
For this job, use the thin batten. Change the station
shape the minimal amount to obtain a fair curve that
touches the corrected load waterline widths. Be sure
that all station sections that need correction are
corrected before going any further.
Usually we pick up another waterline about halfway
between the load waterline and the sheer. Use the
procedure described above for this waterline and again
make all corrections to the stations. It may be that these
connections to the station sections are significant enough
to affect the already fair area of the load waterline. This
type of discrepancy can appear throughout the lofting
process. <strong>The</strong>re are no hard and fast rules as to which
lines should be adjusted if you find such an inconsistency.
Check your measurements and study the
relationship between your lines in the three views. As
mentioned before, visually compare the station sections
for similarity.
A good choice for the next line to fair would be a
buttock that is halfway between the centerline and the
widest point of the load waterline. If you look at the
half breadth view, you will see where the buttock intersects
the deck line up forward and either the deck line
or the transom aft. Using the square, transfer the intersection
point of the buttock and the deck line to the
sheer on the profile plan. This is the forward fixed point
of the buttock. If the buttock runs out before it gets to
the last station aft, use the same process in the stern to
transfer the buttock point to the sheer. If the body plan
shows that the buttock intersects the last station, it is
just a matter of picking up the distance from the baseline
to where the buttock intersects the last station section
and transferring that to the last station in profile.
Place a clean pick-up stick along the buttock line in the
body plan so that one end touches the baseline and the
sharp edge is touching the buttock line. As with the
waterline, label what buttock line the stick represents
and label the end of the stick that touches the baseline
as “base.” Mark all the heights of the station sections,
labeling which mark represents which station, and
transfer all of these distances to their respective stations
in the profile view. Now place a batten on the profile
view touching the buttock mark at each station and
sight it for fairness.
On most buttocks, bending one batten around the
shape of the buttocks may be a problem. On most
hulls, buttocks tend to run with just slight curve in the
midsection of the hull and swoop up sharply towards
the bow and the stern where the buttock runs out on
the sheer. We usually fair the middle of the buttock
line first, using the same batten that we used to fair the
sheer, and draw a light pencil line along it slightly past
the point where the buttock starts to swoop up sharply.
<strong>The</strong>n we remove this batten and use a smaller batten to
fair the buttock where it curves more sharply, carefully
fairing it into the straighter portion of the buttock. You
will find, especially in long, skinny hulls, that as the
buttock swoops up sharply, that area of the buttock
loses most of its effectiveness in fairing the hull due to
the low angle at which it intersects the sections in the
body plan.
Use the same process for fairing the buttock that you
used on the waterline. If, when the buttock is faired, it
is off points that you have picked up from the body
plan, you must then change the body plan to coincide
with the new location of the buttock line at that station.
Again, make all of the changes on the body plan before
going any further. If there is any major change that
will highly distort the body plan in order to make it