Re: [Amel Yacht Owners] Super Maramu rigging loads
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James Alton
Richard, I would be curious to know how much tension can actually be applied via turnbuckles and whether it is actually possible to get to 30 percent of ultimate. The SWL of 1x19 is around 40 percent so if a rig is preloaded to 30 percent it seems likely to me that the SWL could be exceeded pretty easily when sailing loads are considered. The max compression loading of the spar might be more of a concern to me. I am not sure of what wire sizes are used on the SM but 30 percent on 3/8" wire would be around 4 tons of tension/compression per wire x 10 or around 80,000 lbs. Total just sitting at the dock.. The Amel rig has very generous shroud angles due to the chainplates set well outboard and the spar being relatively short so why the need for lots of tension? May I ask why you feel that the Amel rig must be kept very tight and could you provide some actual numbers so that I can understand what you are calling very tight? Sueno was tensioned about the same when I bought her as I would have done which I would roughly estimate to be 5 percent of ultimate on the caps and correspondinly less on the shorter shrouds. The forestay is tighter of course. Her ACMO rigging is original (29 years old) and though it will be replaced this year my surveyor did not find any cracks or failed wire. The bulkheads and every part of the structure containing the rigging loads looked excellent and I would like to keep it that way. I have surveyed and rebuilt a lot of boats with structural damage in this area but no Amels to date. I just do not understand the need for rigging on a cruising boat to be tensioned anywhere close to 30 percent of ultimate but I am curious about why some apparently feel that way? Please provide some technical reasoning behind this position if you can. Thanks, James SV Sueno Amel Maramu #220 Sent from Samsung Mobile -------- Original message --------
From: "Richard03801 richard03801@... [amelyachtowners]" <amelyachtowners@...> Date: 08-11-2016 1:19 PM (GMT-04:00) To: amelyachtowners@... Subject: Re: [Amel Yacht Owners] Super Maramu rigging loads Give the AMEL rig/hull design it is appropriate to keep the rig very tight. The hull engineered to be very tight rig. There MUST not be slack on the Lee side when going to windward. The mast must remain in column at ALL times. No bend fore and aft or side to side. Bill's issue was a "rigger" set the head and aft stays like it was a production boat. That is not appropriate per AMEL. The general rule is tighten each stay keeping the mast in column until it rings when tapped with a wooden hammer handle. If goes thud take a wrench to it. Hope this helps. Fair Winds Smooth Sailing Capt Richard Piller Newport RI Cell 603 767 5330 On Aug 11, 2016, at 11:47, Lokiyawl2 lokiyawl2@... om [amelyachtowners] <amelyachtowners@...> wrote:
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