Hi there,

You mentioned that "When the inner stay is set up hard the pumping generaly eliminated" but that it is undesirable to rig it because of the size of the foretriangle. Does this inner stay interfere with tacking? Why is it undesirable? Is rigging it worse than this pumping?
I have found that most rigs with inline (i.e. single) lowers need some sort of inner forestay to keep the mast from moving about in anything but a light wind (basically, it does the job that forward lowers would do in a more conventinally rigged boat). All this talk of harmonics and waves and whatnot is interesting but seems unlikley to help you go sailing, while rigging your existing inner forestay seems to stop the pumping. If that works, go with it, and try to work around the inconvenience of another stay up forward. If it is an issue of tacking a genoa through that narrow slot, eliminate shackles or knots from your sheets and place some plastic tubing on your inner stay to help things slide. Or set up a runner-like stay that you can release and re-set with each tack - you can use a bungy-cord to retract it automatically when released. The fact that your rig has runners and an inner stay indicates that someone thought them nessessary for some conditions - use them! The window of conditions these were added for may simply encompass a wider range of windspeeds than anyone thought.