[MHml] wire rope splice

[Bill Gibbs]

How is polyester at 43% of breaking strength? 

-----Original Message-----
From: multihulls-bounces at steamradio.com
[mailto:multihulls-bounces at steamradio.com] On Behalf Of Diane Selkirk
Sent: Wednesday, May 23, 2007 6:56 PM
To: Informed discussion of multihull issues
Subject: Re: [MHml] wire rope splice

Bill Gibbs wrote:
> Raising the main sail headcar a couple inches to unlock while sailing
downwind in 35+ knots does require quite a load on the tail.
> What do you figure the max load a motivated (aka "terrified") beefy 
> crew with a 52 winch can apply is?  5,000 pounds?  More?  That's over 70%
of 12mm polyester double braid breaking strength.  Not as big a safety
factor as I thought at first.
>
>   
Double handled winch handle, beefy guy = 65 lbs normally

Add terror = 75 lbs ? x 52 = 3900 lbs. 

Harken says - about 45 lbs maximum (assumes single handle I think) and
normal sized human.

Doubt you can get to 96 lbs (5000/52) unless you are really big (like AC
grinder big).

Then add in friction losses etc.  

I just did a load test on a hand operated davit with a winch with a 50:1
ratio.  Got to 1100 lbs with some effort.  Handle was not ideally placed for
maximum leverage.

Evan Gatehouse

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