Definitions
7.13 Daggerboards and Centerboards

All lift producing elements that have as the pre-dominant purpose to resist sideways movement of the craft while sailing and that aren't canted at a greater angle than 6 degrees of the vertical when the boat is level on the waterline.

A centerboard is only different from a daggerboard in the sense that it is folded or rotated away rather than slid away when in danger of hitting submerged objects.

Rules:
1.6 Daggerboards and rudders

1.6.1 The platform shall be equipped with a pair of rudders.
1.6.2 In addition to the rudders, the platform may also be equipped with a pair of daggerboards or centerboards.
1.6.3 All performance calculations, such as handicap ratings, shall be performed as if a platform has daggerboards or centerboards, even though a particular design may have neither of them.

1.6.4 (Added by vote, August 2007) For the avoidance of doubt, daggerboards/centerboards will conform to the following :
a) Curved/’Banana’ boards will not be allowed.
b) Assymetrical cross-section profile boards will be allowed.
c) Fore/aft movement of the boards when in the down position will not be allowed.
d) End fences/horizontal appendages below the waterline will not be allowed. The board shall be capable of removal, without tools, via the upper opening of the case.
e) There will be no limitation on the daggerboard/centerboard length