Bourton "Big Wave Guns"
BIG WAVE GUNS
 These
designs have been a passion of mine for over 35 years.
The big wave gun category here is referring to boards ranging
up to eight feet only, since the Hawaiian
shapers have a monopoly on the rhino chasers, they have the
right testing ground and all the shapers right there.
Having grown up surfing reef breaks on the west coast of Victoria,
I became aware early what the correct ingredients for a successful
big wave board were, and to this day they have not changed
much at all.
LENGTH
The most obvious change is to add extra length to
a board that is to be ridden in bigger reef breaks.
The extra length allows the board to get in earlier
and delivers more reach out of a turn as
well as having more trim speed, due to extra
surface area.
PLANSHAPE
 When
a board is travelling 3 times it’s normal speed, the
surface area has 3 times the water pressure and so do the
fins, (which are the only mechanisms preventing the board
going sideways). It stands to reason that tails need
to be narrower to take the pressure off the fins;
the board can then be forced in and out of turns with
the same force as a surfer exerts on a small wave board in
small waves. If the tail is too wide the board has to be nursed
through bottom turns and the opportunity for projection is
lost.
Single fin guns needed a forward hip and
wider noses with a long straight into the tail, be it a swallow
or pintail, to help the plan to hug and give the only fin
a chance to hold in the face at high speeds. Since the introduction
of the thruster the 3 fins are now giving the board
more grip, so most contemporary thruster gun designs
have a lot more plan curve in the back half which makes them
a lot looser off the top. Where the waves
are the most powerful in Hawaii, local shapers still keep
the plan curve in the back half straighter to help the board
hug the wave face, although no where as extreme as the early
single fins. The basic centre widths are narrower than normal
as well which again helps them hug and in turn takes the pressure
off the fins.
The tail shape some say is the key to a big gun’s success,
but I venture that there are many other parts of the plan
that can send the board sideways when the pressure is on.
The most popular is the rounded pintail which
has an intense little curve in the last 6 inches of
the plan shape, that in effect loosens the board
off the top but unless quite narrow, is not so positive off
the bottom. The narrow swallow is the opposite;
it is very positive off the bottom but stiffer off the top
but in my opinion it’s biggest advantage is the way
it can sit high and deep in the barrel and
as a result encourages the surfer to shift his body weight
forward when deep without the tail sliding. This is due to
the parallelness of the last 2 feet of the plan, the bight
of the point of the swallow and the decrease in water pressure
in the tail due to the vee cut out of the plan shape to form
the swallow. Whatever your choice these two are the only tails
that can tolerate turning at high speeds.
LATERAL BOTTOM SHAPES
A speed boat’s bottom cops a lot of water pressure
and rarely do you see a hull that is dead flat, in fact most
have an extreme vee at the bow which decreases
toward the stern, and some others in the concave family, namely
catamarans, have the concave for want of a better word all
the way through. It has been my belief that the main
use of the concave is to lift the board off the surface
in order to free it up at low speeds in smaller waves and
similar to the way a skate board can be pumped to gain speed
so can a concave in a surfboard.
If you can imagine a catamaran at 50 k’s an hour compared
to a vee’d mono hull going at the same speed, then both
expected to turn on a sixpence, it ‘s obvious which
one is gonna tip over first. My point is that you
automatically have speed in big waves and the aim should be
to control that speed.
The reverse vee is my choice as it sits down
in the water rather than bouncing around on the surface out
of control. It also has a straighter rail line
through centre to tail than the stringer line so when
on rail it’s going faster and has superior
reach, pretty handy features when you’re caught behind
in the big stuff.
Some shapers use the best of both by using the con
vee which is a forward concave running into
a vee in the tail. The concave in the front delivers
speed under the front foot and the vee in
the tail gives the back foot the power to lever the concave
from rail to rail easier at high speeds. A few Hawaiian shapers
are using this bottom contour with a lot of apparent success
and could be the bottom for guns of the future.
Perhaps it should be said though that the perennial old
channel bottom is still a great bottom design for
clean long walled waves found in Indo and
Polynesia and is always my choice for grip and projection.
Mostly the channels are shaped into a reverse vee bottom but
shaper Alan Byrne has forever used a forward concave, which
at places like G-Land can really open up.
 ROCKER
I made a bunch of guns this year for my team going to Hawaii
and took the punt by dropping the nose lift considerably
and adding it back to the tail lift. Particularly at Sunset
extra length and thickness is needed for paddling. but at
high speeds too much bulk is cumbersome. So if flattening
the nose rocker and in general as a result flattening the
paddling planing area i.e. under the chest gives you early
entry without bulking up you gotta be for it, especially when
the trade off is more tail lift and more freedom. To think
of it bigger waves even if they are super hollow because of
their shear size. the curves are not as tight as a small Kirra
barrel for example where if you’re lacking curve up
front you’re in trouble. One must keep in mind that
the differences with flats and curves in these rockers
are only subtle for the pressures put upon them are intense.
 RAILS
Rail shapes do not change much in shape if anything they
may drop in volume slightly because of the
extra water pressure as well as there is more rail to bury
since the board is longer. Perhaps the most notable difference
is the last foot of the tail where the rail pinches
down for extra bight compared with the small box
rail found on short boards.
FINS
Now this is the tricky part because everyone seems to venture
a different opinion. In the past when tails were more narrow
and drawn, smaller fins if kept on the tail were all that
was needed. It seems nowadays the top level are keeping short
so they can look good off the top and they are good enough
to nurse a wider tail off the bottom without spinning out.
It appears base is necessary and a reduction of area through
the middle and an increase in the tip to deliver that last
thrust seems to be the most popular in Hawaii. One thing that
is common is the cluster position; most shapers
are almost identical with their front and back fin positions.
GLASSING
The perceived benefit of lightweight boards changes somewhat
in bigger waves. like we see with the extreme in tow board
glassing, however there are methods that strengthen the board
laterally without making them over heavy or too rigid nose
to tail. Indo in particularly is a board breaking zone where
there are distinct advantages in keeping the weight off. Placing
a big thick stringer down the centre might strengthen the
board but it restricts the nose to tail flex that most punters
take for granted. There is a 1/8 4 ply stringer on the market
which is a prick to shape but strong as and still flexible
enough so as not to lose that twang off the top and bottom.
In order to steer away from the heavy resin laden 6 oz glass
I have been using a diagonal weave 4 oz for
the past 8 years with tremendous results.
For semi guns in powerful reef conditions we do zero
x 90 degree 4 oz inlays top and bottom coupled with 4 oz diagonal
wraps. To explain an inlay is the first layer that
is only cut to the edge and the wrap is the layer that goes
around the rail. This we call a double diagonal and
have survived time and time again and is a glass job which
is lighter than a 6 x 4 x 6 and heaps stronger laterally.
Because there is only in essence only 2 x 4oz on the deck
it may cop a little more deck denting but I must say that
guns are not surfed like small wave boards and bunny hopped
all over the place so it is less of a concern.
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