Hey Rich,
Interesting discussion!
I don't understand your comments about pin-set spreaders, can you try again? To my understanding, if a swept upper shroud is tightened, the spreader (if loose/pinned) will settle on the position that gives SHORTEST shroud run (a straight line) as turns are taken on. As the spreader will not compress,that section under the spreader is pushed forward, bending the mast. I don't see how this is any different than a fixed base spreader. Am I missing something?
On bendy rigs the spreaders are usually swept back and usually pinned AT the mast; the pins allow the spreader to rotate about the axis of the pin to accommodate the 'new' and variable position of the mast caused by the radical change of geometry due to the (usual) large bends encountered. The reason for this is that when mast bending (for sail shaping purposes and for heel-control) the mast (and spreaders) will automatically 'reposition' itself fore or aft in accordance to the amount of bend - the more bend applied typically the more this section of the mast bows forward, the topmost mast section moves well aft. The cap shrouds for this config. are usually single caps and maybe/sometimes/rarely a single lower shroud.
Since the mast on a bendy is set up to move fore/aft (and at different rates of movement due the varying degrees of bend along the mast ... and on-the-fly mast raking) there is usually a deep mast 'well' for the butt of the mast; the (pinned/fixed) butt of the mast is free to rotate parallel the boats centerline, the
sides of the mast butt (actually several feet above the butt) are held firm by large mast blocks. Fore/aft rotation, especially aft rotation, usually loosens the cap shrouds; so, there are usually 'easily' adjusted turnbuckles (LARGE nuts on the two auxilliary chainplate extenstion) but most simply let the bendy head of the mast lean over sideways ... being restrained 'somewhat' by the bodacious forestay / backstay. Since, most bendy-rigs are set so that mast-raking can be accomplished on-the-fly; .... cant do this if the spreaders are 'fixed' and non-rotatable. As long as there arent any "S" shaped induced bends in the mast (side to side) most bendy rig sailors simply live with the side bend, as such doesnt seem to affect the aerodynamics. Most jibs on bendys are attached to athwartship travellers .... using multi-holed large 'clew-irons' - (replaces the single clew cringle) to adjust for 'twist' - no fore/aft fairleads.
FWIW - most bendy rigs, set up to adjust/tweak from either side of the boat when the crew is well hiked out, will have up to 40 (!!!!!) go-fast & control lines. All this so no one has to 'move' to accomplish any sail shaping/trimming/bilge-board, etc. adjustment - even for boats such as the A-scow with a 7 member crew. For most of the larger scows, surprisingly this has been the typical set up since the late 1800s!!!! Sandbaggers and Chesapeake Log-Canoes also have similar 'complexity'.
The pic that Joe presented is DEFINITELY a bendy rig - and well bent at that. Daveinet's boat with 'slugs' on the main, lack of multipart backstay control, non-tapered mast would more strongly indicate that Johnson put on a 'standard' rig; but, that his mast seem quite 'thin sectioned' would possibly allow correction of that 'too damn full' luff entry shape and well hooked-up/closed leech on his mainsail. When he checks the 'straightness' of that luff - we'll all know and can then give him the 'best' recommendations on how to proceed; until then he's going to have to live with that extremely bad sail shape.
