It would be great if someone tried this out. I can't help thinking though, that a spin that satisfies the mid-girth rule, even if you could furl it, is not going to roll up into a neat package. So probably it will be more 'draggy' than a furled hooter type sail.

Inflatable battens would help (to meet the rule and furl), but from the ones I've looked up, you either get permanently inflated (no furling) or inflated/deflated from a compressor or bottle. Which I'm pretty sure would breach external power rules from ISAF, which we all race under.

I really hope someone has a go at making work.