Great thread. Thanks everyone for the lively discussion.
Let me introduce myself by introducing my boat :-) She is a 40 foot sloop
rigged custom steel
sailboat with very roughly 10,000 pounds in the keel
centered 5 feet below the waterline and mast
rising to just under 50 feet above waterline.
Iím thinking through how Iíll replace the standing rigging (25 years old with some visible corrosion
coming through) with HM fiber synthetics and have some very practical questions and ideas.
First, I apologize in advance for the rough terminology here. I donít have all the terms down. Before you flame me for my questioning ways, take pity on a fellow boater just trying to make sense of the weather
as it comes.
Basic rigging question: My boat has 2 spreaders. All the wires on the sides of the mast are the same diameter except the one that goes outside both spreaders and all the way to the top of the mast. It is larger than the rest. I canít figure out why. Thinking back to freshman physics with vectors and forces it seems that in the more extreme cases the lines below this top line will have at least as high a load. That is if the boat is knocked down and the keel
is exerting its maximum righting moment and the mast strains to pull the sails out of the water
with the waves hopefully helping to bounce the boat back upright the leeward stays will be near slack and the windward stays will be stretched under a very high load. It seems unrealistic to believe there wonít be some stretch in the rigging in the extreme load case even with wire rigging and Iíd think youíd want to keep the mast as straight as possible even if it deviates somewhat from perpendicular to the deck
. Why would anyone use a larger diameter wire for the stay going outside both spreaders to the top of the mast? Unless I can find a compelling reason to do this with the new rigging Iíll simply use the same size rope
for all these lines so they stretch proportionally together maintaining a straight mast. Unless Iím misreading the specs from New England Rope
, HM ropes stretches something like 7 times more than wire so ensuring it all stretches proportionally together seems more important with HM fiber. If anything Iíd be inclined to use larger rope for the lowest lines for two reasons: 1) mass lower in the rigging has a smaller moment than mass higher in the rigging and 2) I always reef the main when the weather
is up and keeping the middle of the mast from sliding out from under the top seems like the challenge here. Thoughts?
Where is the cotter pin? I am scared that the deadeyes from Precourt can be undone any number of ways by potentially well meaning inexperienced crew/passengers who might also be drunk for example. I never worry that a drunk is going to sit down with needle nose pliers and perform the detailed and tricky task of working the cotter pins out of my turnbuckles and then get a sizable wrench to put 30 or 40 turns on the thing to release a wire stay. It is just too difficult a job requiring tools, skill, force, and determination. However, when I look at the Precourt deadeye by comparison it seems to almost invite the curious hand to innocently slacken the line and release the stay. When I set the turnbuckle I put in the cotter pin to ensure it stays put under any conditions. What provides this assurance with deadeyes? Here is the best answer I can think of myself: First, use the largest possible, massively oversized 8mm V-12 vectran looping back and forth between the deadeyes. Second, once all the pre-tensioning is done and the creep has been adjusted for, secure the 8mm V-12 at the point where it leaves the deadeye for the last time with two things: first, put something inside the 12 strand rope to increase the width so it cinches tightly in the hole in the deadeye and cannot pull though... one could even use a properly sized cotter pin :-) and second, just past the embedded cotter pin just thread an aluminum
button sleeve like one might use on 8mm wire and crimp it down. To slacken the line one would have to cut off the crimp. I know you are going to flame me for the crimp idea, but please include a better idea with the flame. There would probably be some trial and error to figure out how to put such a crimp on V-12 effectively without damaging it too much but I wouldnít have to worry about the mast falling down. Comments?
Why put the deadeyes down at deck level where there are uncountable hazards. They seem bigger than turnbuckles and on my deck would impede walking and invite lots of knocks from passers by. Precourt identifies the connection between the deadeye and the deck fitting as the weak link in their parts
and the aluminum
in such proximity to steel
in the presence of salt water
is problematic to say the least. Use something like cast stainless thimbles at both ends and put the deadeyes up off the deck at perhaps arm level or waste level or something. Why doesnít everyone do this?
So instead of turnbuckles Iíll now have cast stainless thimbles and something. Quick Links seem to have larger working loads than shackles of similar size. Would an inspector object to 1/2 inch 316 stainless quicklinks connecting the cast thimble to the deck fitting? Is there a better alternative?
Stretch. Ok, ok, HM braided ropes are low stretch for ropes, but when I look at the numbers from New England
Rope and do some calculations it seems they have about 7 times the stretch of the wire they will be replacing. For example an additional load of 10% of breaking strength of rope that is 50 feet long will stretch it roughly 4 inches. So Iím left imagining a circle of 8 inches diameter (actually an oval) that the head
of the mast will move around inside. Doesnít that seem like a problem? Seems like you definitely need all the lines stretching together to keep the mast straight.
, insurance. If I do this upgrade will they drop me or raise my rates or simply refuse to pay out for a demasting if they find I have HM aloft?
Iím not sure yíall can help with this one, but when I look closely at the attachment points of the wires for the standing rigging on my boat I have a hard time imagining how Iíll get the bulkier thimbles and deadeyes to ďfitĒ. Iím not seeing how I can do a drop in replacement of wire with rope. Iíll probably have to replace/modify/relocate the attachment points/hardware of my boat. This could be the one thing to prevent me from moving forward with this project