The Gougeon Brothers on Boat Construction - WEST SYSTEM Epoxy

Chapter 16 – Lofting 169
Although your square should be perfect, don’t count
on it for precise 90° angles in lofting. Wherever a true
perpendicular is required, take the time to construct it
using a bar compass.
Bar compass: You can make one yourself with slotted
pieces of wood, bolts, washers, and wing nuts, or you
can buy one at a drafting supply house. It is used to
construct perpendicular lines.
Bevel square or adjustable sliding T-bevel: This is
used to transfer angles from the lofting board to various
parts of the boat.
Weights, or hammer and nails: <strong>The</strong>se hold the
battens in position as they are used to fair the curves of
the boat. Drafting weights are available at some drafting
supply stores and are, of course, the handiest to use;
however, a few dozen flatirons or padded bricks will
do, or you can use a hammer and a pound or two of
No. 6 nails.
Battens: <strong>The</strong>se are thin pieces of wood or plastic which
are bent around nails or weights so that you can draw
curves. <strong>The</strong>y are among the more important lofting
tools. You can purchase sets of plastic battens of
varying flexibility from drafting supply houses, or you
can manufacture wooden battens yourself. <strong>The</strong> plastic
battens are usually used to lay down the body plan
where the curves are tighter, whereas wooden battens
are usually used to fair waterlines, diagonals, buttocks,
and profile lines.
Spruce or clear white pine of the straightest grain you
can find seem to be the best materials out of which to
make battens. Most hardwoods are not too satisfactory
because they tend to take and hold shape when left
curved. An exception to this is that you can use a thin
ash batten to lay out the station sections of the body
plan or sharp curves in the stem and buttocks.
We usually lay in several 1" � 4" (19mm � 89mm)
boards of clear pine for battens and rip them up to
varying sizes depending on what we need. As the
lofting progresses, different batten sizes may be desired,
so a little extra material to make specialized battens
comes in handy. Make one main batten that is 5' or 6'
(2m) longer than the length of the boat. It should be
about 3 ⁄4" (18mm) square for a small boat, and about 1"
(25mm) square for a larger boat. We use a 20-to-1 scarf
in making up battens because the longer the scarf, the
less likely it is that the scarf will cause a hard spot or
kink in the batten. <strong>The</strong> main job of the batten is to
allow you to sight the expanded lines of the boat and
find areas of error. A crooked or kinky batten will make
this job difficult.
<strong>The</strong> process of fairing will be much easier if you paint
your battens flat black. <strong>The</strong> black is in sharp contrast
to the white lofting floor and eliminates color variations
in the grain of the wood. Using non-glossy paint will
minimize harsh glare spots, as will the use of indirect
lighting over the lofting floor.
Pens and pencils: You will need several ballpoint pens
with different ink colors, several hard lead pencils, a
pencil sharpener, and a felt tip pen. Be sure to use
waterproof pens and markers; there are few things
more irritating than finding that your wet feet have
blurred your carefully drawn lines.
Kneepads or a movable foam cushion: <strong>The</strong> lofting
process will be far more comfortable if you have
something to kneel on.
Stock for measuring sticks and pick-up sticks: Have
on hand some scrap lumber or a few pieces of 1" � 4"
stock which can be ripped into strips. You will need to
make up approximately 15 sticks, half of them as long
as your boat is high from the baseline and half of them
about as wide as its biggest half breadth dimension.
Ideally, the sticks should be slightly wedge-shaped in
section so that one edge makes a point.
Stock for blocks: Have enough 1" � 2" (19mm �
38mm) material on hand to make 6" (150mm) long
blocks. You will need one block for each station line
in your lofting.
Cable and string: Lengths of cable and string will be
used to lay out your lofting grid and must be at least as
long as your lofting floor. <strong>The</strong> cable will have to stand
up to about 500 pounds of tension and should be
about 1 ⁄16" (2mm) in diameter.
Laying Out the Grid
<strong>The</strong> first step in lofting is to lay out the grid for the
three views. <strong>The</strong> grid is the general name denoting all
of the straight lines that represent the locations of the