My DS1 has a cuddy stepped mast and a mast jack. I freed the plate on the jack, and now it turns easily. I've never had a mast jack before. Seems like a nice, easy way to adjust the shroud tension for the wind, especially if the jib halyard is providing tension on the forestay line. I notice that some posts seem to imply this is illegal for racing, however.
I assume that when the shrouds are at sailing tension, the jack set just high enough so that when lowered to the bottom it unloads the forestay and makes it easier to detach and then re-attach the stay when stepping the mast. Or, does the jack tend to slip when underway and does everyone just leave the plate at the bottom and do all tensioning with the turnbuckles? Or, is there some mystical incantation that must be used in determining a proper setting. Should I ask Hermione or Harry (Potter that is)?
Dan