RIG CH.9 Flashcards
When are snatch blocks used?
To redirect lines
Where can you find the weight rating of snatch blocks?
Stamped on the hook or shell
Explain the tension angle relationship.
When angle decreases, tension increases
What is the line in tension?
The tension found on the line from the weight to the snatch block. It is equal to the weight.
What is the line out tension?
The tension found on the line from the snatch block to the ground. It is equal to the weight times 10% friction
What is the equation for snatch block tension?
Snatch block tension = line out * angle factor
The rope angle is 180, what is the angle factor?
0
The rope angle is 120, what is the angle factor?
1
The rope angle is 90, what is the angle factor?
1.41
The rope angle is 60, what is the angle factor?
1.73
The rope angle is 45, what is the angle factor?
1.84
The rope angle is 0, what is the angle factor?
2
What are the steps to calculate multiple snatch blocks?
- calculate friction throughout line 2. Remember line out for the first block will be the line in for the second block
