Let’s look at this rigging load chart. Specifically, let’s look at wire rope size 3/4”.
• At wire rope size 3/4” the shackle must be at least 7/8” according to this manufacturer. Oversizing is ok; however, the shackle must be at least one size larger than the rigging rope diameter.
• At wire rope size 3/4” vertical capacity is 9800 pounds.
• At wire rope size 3/4” two leg 90-degree basket capacity is 19600 pounds, or twice vertical. This is always the case, 90-degree basket capacity is 2x vertical.
• At wire rope size 3/4” choker capacity is 7200 pounds. Choker capacity is usually about 75% of vertical always. That’s interesting.
Now let’s talk about Sling Angle Factor.
• At 3/4” wire rope size 90-degree two leg basket capacity is 19600 pounds.
• As the sling angle drops to 60 degrees capacity drops to 16900 pounds.
• Drop the sling angle to 30 degrees and capacity drop to 9800 or the capacity in vertical single leg capacity, wow. So, it’s true, as sling angle drops, stress goes up capacity goes down.
• At the bottom, the chart says, “sling angles of less than 30 degrees are not recommended”. Remember, sling capacity changes with configuration!