Fins

A fin is not pinned to fixed coordinates. Its lateral position is an inset from the rail, and its base rides the bottom rocker surface — so when you change the outline or the profile, the fins move with the board, exactly as a shaper marks a blank relative to the rail and the tail.

What is saved is the intent — the setup, the system, the specs — and the actual geometry is computed against the current shape whenever it is needed.

How many fins, and where they sit.

No fins

No fins — the default, and what every geometry calculation assumes unless you add them.

Single

One centre fin. Longboards and classic single-fin shapes.

Twin

Two side fins, no centre. Loose and fast through the flats.

Thruster

Two side fins plus a centre fin. The default modern arrangement.

Quad

Four fins, two per side, no centre.

2 + 1

Two side fins plus a centre box — the longboard/mid-length convention.

5-Fin

Five boxes so the board can be ridden as a thruster or a quad.

The mounting system determines the box or plug geometry routed into the board, which is what appears in the exports.

Glass-on

Fins laminated directly to the board. No box, so nothing is routed.

FCS II

A continuous routed slot per fin.

FCS (x2 plug)

Two round plugs per fin, about 3″ centre to centre.

Futures

One continuous box per fin, deeper on the sides than the centre.

Blade outline templates, used to draw and size the fin itself.

Thruster / side

Upright, moderate rake — the general-purpose modern template.

Single

Larger, more raked centre-fin outline.

Noserider

Deep, heavily raked longboard fin for holding a nose ride.

Keel / twin

Short, long-based swept fin for fish and twin setups.

Fin positions carry through to the hollow wooden frame templates as etched reference marks, and onto the spec sheet, so they come out with the rest of the board rather than being marked separately.