Generally with Structural Furlers you need to have a much higher halyard tension, just as on a True (Racing) Code Zero
. Because the halyard is doing the job of both the stay, as well as that of a halyard. So the loadings on them can be much higher, thus necessitating a purchase
system on the halyard, & possibly on the tack of the sail/furler at deck level as well. Which puts a lot more loading onto the spar, as well as the boat
. Plus the sail. And it also necessitates a different sail shape design, to even come close to the upwind ability of a standard jib/genoa.
With Code 0's it's common to have a multi-part purchase
on the halyard, as well as monsterous backstay loads as well in order to get decent luff tension on the sails. Which produces significantly higher rigging
loads than anywhere on the boat
. To the point where boats get bent, & sometimes broken by such loads if the crew goes wild tensioning things.
Though even with this, loose luffed headsails can't point like standard ones do. So you'd be best going with a regular furler.