Originally Posted by cwjohm
In any case it seems that the three systems are simply arranged to get the head to the top of the mast in an elegant fashion, and once the head is at the very top the halyard in effect takes the pressure.
Correct -- The halyard takes the weight of the sail the whole way in both the Lagoon
and the Doyle systems -- but what makes it perhaps something other than 'simple' is the other part of the process, viz.
detaching the uppermost batten when lowering the sail so that the lowered sail lies flat (relatively) against the boom.
The systems -- There are probably only two because the 2 rings in the picture are simply 2 attaching points in the one top car -- are all about allowing the top batten to lie down when the sail is lowered, and then rise up again when the sail is raised, both occurring automatically. The difference between the systems appears to be that the Lagoon
system uses an extra line (a small spectra line anchored at the third batten and the top car) whereas the Doyle system uses a loop in the halyard passing through a detachable 2-part top car assembly. The Lagoon system rises (and lowers) the top batten as the gap opens (and closes) between the upper battens, thus tensioning (or relaxing) the spectra line. The Doyle system brings the top car together as the tension increases on the halyard.