Hey Bearcave.......good thought !

The crescents, as you mention, may well have been introduced as an after thought to improve the self righting - IF - the board was to light, cutting away the volume of the rail would decrease the effective buoyancy and therefore allow the board to sink better down to the required rotational axis - allowing it to self right easier.

This issue can be seen in the thicker custom boards - needing more weight, rather to sink the board down to its rotation axis line - rather than to counter the surfers weight.

Bro ********. ...
Share the STOKE !

Common.......I'm waiting for that 'Headcam' footage..........even the test video you spoke about.......LOL