Bill,
So you have preloaded your rig by your estimate to as much as 30 percent of it's ultimate strength? That may well be more load than the rig will see even under severe conditions. The preloading effectively reduces the remaining safety factor of the max compression loading of the spar... Also consider that plastic deforms over time under load. Ever noticed how an improperly blocked fiberglass hull can take a permanent set when too much load is concentrated at one point of the hull for a long period of time? Yes, the structure is strong but push or pull hard enough for long periods and deformation will occur. On a cruisng boat I tune to keep the spar to remain straight in all conditions (verified by loading up the rig and sighting the sail track) but tight enough that the lee rigging is not excessively slack. If the boat is to be at rest for an extended period I reduce rigging tension. Hopefully others will comment.
Best,
James
SV Sueno, Maramu #220
-------- Original message --------
From: "
william_maffei@... [amelyachtowners]" <
amelyachtowners@...>
Date: 08-11-2016 10:57 AM (GMT-04:00)
To:
amelyachtowners@... Subject: [Amel Yacht Owners] Super Maramu rigging loads
Hey everyone -
I know this topic has been addressed before. I have recently tuned my rig and it was crazy to me to the amount of work that was involved. This traces back to a previous post I had made about the forestay being wobbly. The problem (which I never thought) was the rig. Needed to be tightened (a lot). The pin actually came loose while furling the jib and that was the only problem. Now, I had my rig professionally serviced and tuned and as we all know this is a controversial topic among "professional" riggers without Amel experience. So I did the job myself with the help from another owner. My rig is so tight now you could play music off it. Actually when you tap the backstay it sounds like George Lucus used this to replicate the blaster sounds from Starwars. HAHA. Anyways, I called my rigger and he was very interested to come take a look. He was shocked... I mean literally shocked. Told me
it goes against everything he has ever learned about rigging boats. His gauges were not even able to read the loads of the stays. Told me that other boats would have collapsed on themselves under the loads but at the same time agreed to the tensions. His question and the reason I am writing this is to find out if anyone has numbers for him. I guess the average numbers are 15-30% of the break load... (???) Can anyone chime in on this topic? Provide some numbers I can write down and relay? Any stories about tuning their rigs? Hope all is well and fair winds!
Bill Maffei
SM #195
It's all Good
