SailNet Community - View Single Post - A couple wisely decides to head back in...
View Single Post
post #26 of Old 03-29-2013
Senior Member
RichH's Avatar
Join Date: Jul 2000
Location: Pennsylvania
Posts: 4,372
Thanks: 42
Thanked 236 Times in 223 Posts
Rep Power: 18
Re: A couple wisely decides to head back in...

Originally Posted by mr_f View Post
Why are their lifelines so loose? (This is an honest question. Rephrased: are my lifelines too tight?)
Structurally looser life lines (and jack lines) will be 'stronger' vs. impact and 'side forces' (load applied at ~90 to the long axis of the wire.

Mathematically, with a 'tight' cable or line if you apply a load perpendicularly, the resultant loads 'along' the cable or line begin to approach 'infinity' (dividing by the trigonmetric SINE of the angle .... dividing by 'near zero' winds up being a very LARGE number, or a VERY large applied stress); however the innate elasticity/stretch of the cable or line at max. stretch will relieve those angles (making those angles larger than 'zero' at the two attachment points of the cable or line).

Suffice it to say that your lifelines need to be well over ten times stronger than the max. impact load expected and applied at 90 to the long axis of the wire ... and then you always add a 'safety factor' on top of that.

Obviously you dont want 'sloppy loose' lifelines as that promotes a 'functional' failure.

Rx: dont make your life lines or jack lines 'bar tight'; a little 'slop' in the wire is 'useful' from a 'strength' viewpoint.

Last edited by RichH; 03-29-2013 at 01:16 PM.
RichH is offline  
Quote Share with Facebook
For the best viewing experience please update your browser to Google Chrome