I've logged over a thousand miles sailing this year in varying conditions but mostly moderate to heavy air (10-25 knots) and I've come to the conclusion that the rig wants to be set up with more pre-bend than most people might think is reasonable for a straight section mast. I replaced all standing rigging two seasons ago and it has creeped out several times and I have re-tightened three times now (shrouds only). Hopefully the last time was it. My goal was to tighten enough so that all slack is removed when fully powered upwind, heeling more than 20 degrees. Because of the shroud geometry with the aft lower being essentially in the same plane as the upper, the only way I could remove the slack was to have fairly significant tension in all shrouds. I don't have a Loos gage but everything is quite tight. The necessary pre-bend seems to be on the order of 3 inches with a just tight backstay (I use hydraulics). In part, the adjustable backstay requires tighter shrouds because when you put tension on the backstay and bend the mast further, the forward lower loosens. So, you need to take up tension in that lower and this creates the static pre-bend. If you don't have an adjustable backstay and/or generally carry less headstay tension then you can carry less tension in your shrouds if you accept that they might be a tad slack to leeward. Personally, I find the pre-bend fine as it doesn't seem to really impact mainsail shape too much and we generally depower our mains quickly on the wind as the wind comes up. I really want to keep mast pumping to a minimum and this seems like the best solution without resorting to a babystay. Just thought someone may benefit from my observations. The downside to this shroud tension scheme is that my head door is now slightly misaligned due to distortion in the port side transverse bulkhead. It still fits the frame but I need to reposition the latch.
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