Re: RE: WANTED - M816 Snatch Block AKA Tackle Block/Sheave A
rizzo said:
I think you are wrong. the lifting capacity of the crane is rated at 20k not the winch. I have never seen a rating on the winch. I assumed that since it has a 1/2 inch cable that it is rated the same as the front deuce winch. I havnt done the research, I'm going from memory of previous reads so I may be wrong.
I disagree. The -10 TM is not real clear on this point. Page 1-15 of the 14 June 1985 edition of the TM states "The vehicle crane is used for lifting operations of up to 20,000 pounds", which would lead one to believe the CRANE itself can lift 20,000 pounds, but that is not exactly what the TM states. "Used used for lifting operations of up to 20,000 pounds" is not the same as stating "The lifting capacity of the crane is 20,000 pounds".
This issue is either clarified or made more confusing by reading the "CRANE CAPACITY"
data plate on page 2-155 of the same TM (see below). It states the crane capacity with outriggers set and boom fully retracted as 10,000 pounds with TWO part hoist line.
However, if you read the very fine print below the capacity table (this is where I needed the magnifying glass), it states "Maximum capacity with boom retracted and boom supported to frame - 20,000 pounds @ 10 ft radius and outriggers down 3 part line. 20,000 pounds @ 15 ft radius with boom jacks to ground 3 part line - rear outriggers up".
If the boom is being supported by either the boom supports or boom jacks, then the crane itself is NOT lifting anything, it is the crane winch providing all of the lifting effort. All the crane is doing is providing a conduit for the winch cable.
Hence my conclusion is that the capacity of hydraulic crane itself is only 10,000 pounds, the winch capacity, with the boom properly supported, is 20,000 pounds WITH 3 part line. Of course, that would mean the actual winch capacity running a single line would be in the neighborhood of 6800 pounds.
