Originally Posted by davidpm
OK I think I got it.
The first couple of paragraphs says the the most wear with wire rope in crane service is rolling over the pulleys caused damage to wire.
Usually, fatigue breaks develop in segments of the rope surface that come into direct contact with a sheave or drum.
If that is the case then bad strands will show up before any other damage is critical in a crane.
With a boat since the wire don't move it can fail first in places that can not be seen.
Shock can cause metal fatigue, and it occurs at a molecular level and cannot be seen by the naked eye until it is just about too late. I am not a rigger, but I have been in the oilfields long enough to know what happens when a wire rope or cable parts under pressure. I also owned part of and operated Trans-System Pipe and Storage in the Port of Houston for several years, we had an electro magnetic inspection system on site for inspecting oilfield pipe, you could see defects in the pipe wall area and the end areas under the EMI that were absolutely undetectable to anyone with the naked or any other kind of eye, the flaws were micrfissures in the wall of the pipe.
I wish I had thought about it at the time, as I no longer own any part of the business, I could have made spare change on the weekends by figuring our some way to put the rigging on a board and running it through the EMI LOL.
If it is 35 years old I would replace it, it sucks to spend the money, but it sucks more to die. As to the guy who says that sailing to the Bahamas or other islands is not a big deal...he must not have ever sailed in the storms that come up out there, very suddenly sometimes, and often very harsh when they do come up. I would not like to get dismasted out there.