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Fin Box Types
Related links: New
fins, Used
fins, Metric conversion table, Fin
Selector
A-box, E-box,
Tiga box, Trim box, Tuttle box,
Deep Tuttle box, and Meritex box
| A-box
"American" |
 |
| Type: |
Screw from bottom
Number of screws: 1 on front tab |
| Tapered sides: |
No |
| Adjustable: |
Yes |
| Primarily found: |
Most common box found on short boards in U.S. |
| Aka: |
Chinook box, Freestyle fin box |
| A-box stands for
American box. It was first used by the surfing
industry when fin
boxes were
invented. In fact, there was a patent on it for years. The
windsurfing industry adopted it many years ago. Chinook
sailing products in the Gorge modified it from the original two-piece box to a one-piece box, which made it much stronger.
The concept uses a roll pin
on one end of the fin, (in windsurfing it is on the back), and
then a tab on the front through which a hole is drilled. A
machine screw goes through the hole in the fin, into a slider
plate in the fin box. This is how the fin is
tightened. This fin box is still one of the most popular
styles of fins in the Gorge, and the US. The standard
screw size is a #8 machine screw, 7/8" long (pan head). |
| E-box
"European" |
|
| Type: |
Screw from bottom
Number of screws: 1 on front tab |
| Tapered sides: |
No |
| Adjustable: |
Yes |
| Primarily found: |
Found on many older production boards (pre-
1990). |
| Aka: |
Production box, |
| E-box stands for
European box. It is almost identical to the A-box
(American), but is a little deeper, and a little wider. An
A-box fin can work in an E-box, with some shims. The
concept uses a roll pin
on one end of the fin, (in windsurfing it is on the back), and
then a tab on the front through which a hole is drilled. A
machine screw goes through the hole in the fin, into a slider
plate in the fin box. This is how the fin is
tightened. The standard screw for the E-box is a 4 mm
diameter screw, the length, about 25mm long. |
| Power
box |
 |
| Type: |
"Through the deck" |
| Tapered sides: |
Yes |
| Adjustable: |
No |
| Primarily found: |
Many production boards use this box: F2,
Mistral, Hifly, RRD, and many others. |
| The Power Box is used in many production
boards today. It uses one screw
through the deck of the board, into the center of the fin.
Both the sidewalls, and the ends are tapered, so it usually
achieves a tight fit. Like with all "through the
deck" boxes, a rubber
washer should be used on the screw ( in addition to the
metal one) to seal off any air from the deck of the board,
otherwise spinout can easily occur. |
| Tiga
box |
 |
| Type: |
"Through the deck" |
| Tapered sides: |
No |
| Adjustable: |
No |
| Primarily found: |
Found only on older Tiga boards. |
| The Tiga fin box is not very
common anymore. It used two screws from
the deck like the Tuttle box, but had rounder
corners. It is important when using any
"through the deck" box to use a rubber washer (in
addition to a metal one) on the screws so that no air leaks from
the deck to around the fin. If air leaks, it can cause
some spinout.
|
| Trim
box |
 |
| Type: |
"Through the deck" |
| Tapered sides: |
Yes |
| Adjustable: |
Yes |
| Primarily found: |
Primarily found on Bic brand boards |
| Aka: |
Bic box |
| A Trim box is a
"through the deck" fin box that is used on Bic
boards. It is the only "through the deck" box
that is adjustable fore and
aft. It uses one screw
from the deck which goes into one of the two to five holes in
the fin. It is important when using any
"through the deck" box to use a rubber washer (in
addition to a metal one) on the screws so that no air leaks from
the deck to around the fin. If air leaks, it can cause
some spinout.
|
| Tuttle
box |
 |
| Type: |
"Through the deck" |
| Tapered sides: |
No |
| Adjustable: |
No |
| Primarily found: |
Primarily found on Race boards, but also found
on many large production boards. |
| Aka: |
"Race box" |
| The Tuttle
finbox is most often used in race boards. This type of
finbox goes completely through the board making it very strong
and light. This type of box is used primarily in race
boards, but has also found its way into other boards. It
uses two screws from the deck of the board, into the fin to
secure the fin to the board. The screws are usually
1/4" diameter (20 threads per inch). The length
depends on the thickness of the board, but the lengths can range
from 1" to 3". It is important when using any
"through the deck" box to use a rubber washer (in
addition to a metal one) on the screws so that no air leaks from
the deck to around the fin. If air leaks, it can cause
some spinout.
|
| Deep
Tuttle box |
 |
|
Type: |
"Through
the deck" |
|
Tapered sides:
|
No |
|
Adjustable:
|
No |
| Primarily found: |
Primarily found on Race boards, but also found
on many large production boards. |
| Aka: |
|
|
The Deep Tuttle fin box is most often used in race boards or big light wind
boards. This type of fin box goes completely through the board making it very strong
and light. This type of fin box is used in higher volume
boards, in order to accommodate larger (60-70cm)
fins. It is the strongest box for such
large fins. It
uses two screws from the deck of the board, into the fin to
secure the fin to the board. The screws are usually
1/4" diameter (20 threads per inch). The length
depends on the thickness of the board, but the lengths can range
from 1" to 3". It is important when using any
"through the deck" box to use a rubber washer (in
addition to a metal one) on the screws so that no air leaks from
the deck to around the fin. If air leaks, it can cause
some spinout.
|
| Meritex
box |
 |
| Type: |
"Through the deck" |
| Tapered sides: |
No |
| Adjustable: |
No |
| Primarily found: |
Found almost exclusively on Mike's
Lab and Real Wind boards. |
| Aka: |
|
| The
Meritex box is rarely
used. It is similar to the Tuttle box,
except it's shorter and uses only one screw
through the top of the board (not two).
|
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