40 COACHING FUNDAMENTALS
Different fin heads: (from top to bottom) deep tuttle box,
tuttle box, power box, US box, slot box (single bolt)
Fin types include:
1) Freeride/freemove/freerace: single centre fin –
designed to give the best of everything. Relatively long,
upright in the mid section to push through the feet for
lift/blasting. Has a gently swept tip to keep the tail under
control in carving turns.
2) Wave: small, very swept back fins to enable the best
range of movement on a wave face. Can be set up as
either a thruster, quad, single, or twin (with single and
twin not so common these days). Modern wave boards
often have five fin boxes (one US box plus four Slotbox or
five Slotbox) to give the option of thruster or quad setup
(or possibly twin or single setup if required).
3) Freewave: between freeride and wave, mostly with the
option of either a single freeride centre fin or a
thruster setup.
4) Slalom/race: single, long, straight centre fin = early
planing and raw power for specialist high-wind racing.
These are typically the longest of all fins with the
straightest profile to provide the drive needed against the
biggest sails that can be held onto. Thin, low-drag profiles
give quick acceleration with control at extreme top speed.
5) Freestyle: single, very short (typically 15-24cm), stubby
centre fin with a thin profile for fast, upright-stance early
planing, high manoeuvrability and ease of sliding. To the
uninitiated, freestyle boards are very hard to sail in a
straight line as the fin offers such little support for a
normal, outboard stance making it prone to spinout.
6) Speed: single, relatively long/straight centre fin with
specific rake angle and low drag characteristics for high
speed, straight line speed challenges.
7) Weed: heavily-raked versions of regular fins to allow
weed to slide off to avoid the board slowing or tripping at
speed over unwelcome patches of seaweed.
8) Delta: single, fast, very low-profile (squashed triangle) for
slalom and speed in shallow spots and also suitable for
thick seaweed.
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WIND
SURFING
Boxes
A fin box is the slot in the board that the fin is bolted into. Fin
heads, of course, must match the box to enable them to be
used. The current main types of box are:
• Power box: typically on freeride boards using a single M6
bolt through the top of the board. The fin needs to fit
snugly having only one fixing.
• US box: typically the centre fin position on
wave/freewave boards for a thruster setup or for a single
fin. Held by a captive pin through the rear of the fin head
and a M4 bolt under the board with a square brass nut at
the front. US box fins can be sacrificial. The front piece of
the head is designed to snap on impact in shallow water
to save the box being ripped out of the board.
• Slot box: typically the two or four outer fin positions (or all
three, four or five positions) on wave boards for thruster or
quad setups. Uses either two M5 bolts through the
underside of the board or one bolt if the front of the fin
head hooks under a fitting in the front of the box.
• Tuttle box or Deep Tuttle box: typically slalom, freerace
or bigger freeride boards using two M6 bolts through the
top of the board. Sometimes called Foil box when heavily
reinforced for foil specific or foil-ready boards.
On multi-fin boards, slot box covers/blanking plates can be
used to cover any unused slots if required to reduce drag. If
fins can be moved forward or back in the box (i.e. with US
and Slot boxes but not with Tuttle or Power boxes) then
moving forwards gives a looser feel for better carving and
moving backwards gives more stability for blasting.
Fin selection
Selecting the right fin is as important as your choice of board
and sail yet is often overlooked. When you buy a new or used
board and get just one fin option with it (one single fin or one
set of multi-fins) then that’s what you’re going to use. On some
days this will work whilst on others you might have control
issues. You need more than one option to match different
conditions and sail sizes. Operating a one-option policy for fins
is perhaps like owning a pair of flip flops and using them for
everything. On some days you will get by just fine yet on others,
like when you’re being chased by a hungry polar bear down a
snowy slope, you might wish you had something more suitable.
Having a range of fins is the key to balancing the power
in the sail to maintain control