Re: bowline on a bight
Say I want to install a 5/8" block on a bull rope using a bowline-on-a-bight. Only one of the two loops formed will fit into the attachment pin pulley. Is it acceptable to do this? Otherwise, what's a recommended knot for this application that will actually come out after she's loaded to several thousand pounds? This is a snatch block w/ come-along application by the way.
Hi, all. Plasmech, getting back to the original post, I can see that there might be instances in your set up where no knot might work. Simply pass one end of the anchor rope in one side of the block out the other and let the block sit in the middle of the line. This is the line you are using to anchor the block. Anchor the 2 ends of the rope around whatever the anchor is to be and let the block float to the midpoint of the rope. You would not have to worry about one side being loaded more heavily than the other. This would, I am sure, would not be the way to go with every job, but it might work for you here. Obviously, the working line-the lowering line or tensioning line- whatever rope you use in the block needs to be the weakest link. I would also mention that no knot is easier to untie than any other knot, or at least in my experience.
I also would mention that the SS 5/8 arborist block, it is made by CMI, is rated for 2,800 lbs WLL. It is a real nice block, I have one and use it alot, but several thousand lbs load is too high. Go for the 3/4' model of the same thing and you can use 5/8 rope in it no problem (as per conversation with Wes Spur). Then you can use 3/4 rope for the anchor rope and not have to do a dance to adhere to the weakest link rule. You really don't want the anchor to break and have that big hunk of metal come flying straight at you.
eljefe