I’ve been wondering about the same thing, as it applies to kneelo designs. Seeing as bodyboards work so well in steep situations and barrels, it seems to me that the crescent tail would also translate to working well for both standup and kneelo. Just a thought…
A shaper friend of mine has recently started putting them on his own boards as he was getting sick of rounded square tails. He regards it as a cross between a rounded pin and a swallow alternative. His crescent or half moon tails are pulled in just like a rounded pin but as if the last part of the pin has been cut away. Hope that males sense to you.
tail shapes on a bodyboard do effect the ride cresents are a bit stiffer on a sponge than either bat or round tail but they do hold in the barrel better. and Lee when in the barrell if you look at photos of me from when i would sponge my feet are out of the water and all the weight is shifted to the inside rail. i made barrels none of my friends who bodyboarded would make becuase they draged their legs.
Mandala has made a board called the Dark Cloud that is a combination of crescent/swallow style tail which Alex Kopps thought up. I have shaped/glassed a similar board and will say, although it looks beautiful and really cool, glassing the tail was quite difficult. Sanding, and shaping was really enjoyable. No hassles on that part. I would say it performs close to a fish or square tail but just a little looser. Less thrust on turns obviously.
To me it looks like it would be similar to a rounded square more than a swallow i.e an in between tailsahpe that has some of the turning of a rounded square with a bit more bite(sharper corner) but just guessing…