> My 1995 (#804) has 1/8" 1x19 rigging and chainplate thickness. Too much
> pull on the 4:1 backstay tensioner can easily put 500 pounds tension on the
> forestay, which according to my sources has a fail strength of only 1200
> pounds. About 300 pounds would be the static SWL, and a 30 knot puff adds
> some 300# more force.
> Regards, Mac
Hi Mac,
Oops. You have at least one error there, I think : ^ (
1/8" 1x 19 wire has a breaking strength of at 2100 pounds, not 1200,
according to West Marine's 1999 catalog and one of my rigging books.
As for your number of 500 pounds of tension that you could apply with your
backstay adjuster -- 500 pounds is entirely hypothetical and not even close
to what happens in the real world. Why would you put 125 pounds of effort
into tightening your backstay. You wouldn't use 125 pounds of effort to
tighten your turnbuckles until they were two blocked. You don't use 125
pounds of pressure to hold your tiller. You don't even use 125 pounds of
effort to trim a jib on a very windy day. Why on earth would you put 125
pounds of effort into adjusting your backstay!!! ???
Let's talk about the real numbers -- not what you "imagine" the force you
"could" be able to put on it. IT'S 100-200 POUNDS OF TENSION TO ADJUST THE
BACKSTY IN THE REAL WORLD.
I can trim and ease the backstay easily, with just a FEW pounds of force (it
feels about the same as the mainsheet). I've been lifting barbells for 30
years now, and I'd estimate that I put an absolute MAXIMUM of 10 pounds worth
of biceps into the effort. 10 pounds at 12:1 gives me an 120 pounds of stay
tension to bend the mast
If I use these new numbers in your analysis (assuming it's a valid analsis),
it doesn'tappear I should worry about my mast coming down (120# backstay +
300# static load + 300# for gusts = 720# of strain on the wire with a
strength 2100#) . At least not for the reasons you thought I should worry.
You haven't convinced me yet hat my mast/backstay is going to cause my boat
to implode the next time I go out : ^ )
I don't analyse the loads.
I JUST SAIL THE DANGED BOAT THE WAY IT CAME RIGGED FROM THE FACTORY!!!!
Best,
Judy.