The Gougeon Brothers on Boat Construction - WEST SYSTEM Epoxy

Chapter 16 – Lofting 175
crowded for the centerline and use a different ink
color. <strong>The</strong>n take the marked stick over to the body
plan grid and transfer all of the information to the
appropriate waterlines, diagonals, and buttocks.
Remember that the deck and profile have already been
faired and won’t appear on the measuring stick.
When you have laid out all the points, bend a thin
batten around them, trying to make it touch them all.
Hold it in place with small nails—on either side of the
batten, not hammered through it—or weights. If you
find gross errors, go through the checking process
explained earlier. Adjust the batten, moving it as little
as possible from the points, until you have a fair, even
curve, and then draw in the line in pencil.
Lay out the rest of the station sections in this manner.
We suggest laying down the points for only one station
section and rough fairing that station section before you
go on to another. Some station section lines will cross
each other and if points exist for several sections, this
can get somewhat confusing.
It will help a little bit when it comes to final fairing
if you use some consistency while rough fairing the
section lines of the body plan. For example, if you
move station 3 out slightly on the load waterline and
station 2 needs correction in that area, make the correction
on station 2 by moving it out slightly at the load
waterline rather than moving it in on waterline 1. By
the time the body plan is laid down, although the boat
is by no means fair yet, it is quite easy to envision the
shape. Unless a major error is found, the section of the
aftermost station in the body plan usually remains. On
the forward half of the body plan, there is sometimes
a line close to the centerline, but not necessarily parallel
to it, which represents the thickness of the boat at
the point where the planking ends, but before any
rounding of the stem has taken place. You need to draw
this line in also. It will later be used to determine the
distance from center of the waterlines at the point
where they run out past the stem. Some designers draw
a light line in the profile view called a fairing line,
which will appear to be some distance ahead of the
stem, for the sole purpose of determining where the
waterlines and diagonals, if slightly extended, would
intersect with the centerline. (See Figure 16-8.)
Baseline/Centerline
Severely radiused stem provides no
accurate control points for fairing
waterlines and diagonals
Figure 16-8 A profile fairing line at the intersection of
projected longitudinal hull lines.
At this point, on some hulls, we subtract planking
thickness. This procedure is discussed later in the
chapter.
Fairing line
based on
projections
of deck and
waterlines
Fairing the Longitudinal Lines
<strong>The</strong> next job, and it is a long one but the essence of the
lofting process, is to check the fairness of the body plan
sections using the waterlines, buttocks, and diagonals
as tools. This process will require continual
readjustment and fairing of all the lines until the
measurements and intersections correspond in all
views. <strong>The</strong> offsets will no longer be used except to
check gross errors. Instead, the dimensions will be
picked up from the lines already laid down in the
lofting.
We usually start the fairing process at the load waterline.
Select a pick-up stick that is longer than the
widest point at the load waterline of the boat. Place it
with its sharp edge touching the load waterline and one
well-squared end touching the centerline of the body
plan. Label the pick-up stick “load waterline” and label
the end that is touching the centerline “centerline.”
Being careful not to move the stick, transfer the widths
of the load waterline at each station to the stick. You
will, of course, need to lay the stick on both sides of the
body plan in order to pick up the dimensions of the
load waterline at every station in the boat. <strong>The</strong>n take
the stick to the half breadth view and use it to lay out
the waterline widths on their respective stations.
In the profile view, the load waterline will intersect the