USCG Exam PracticeCargo gear and rigging
What is the theoretical mechanical advantage of a luff tackle?
- A. One or two, depending on which block moves
- B. Two or three, depending on which block moves
- ✓ Three or four, depending on which block movesCorrect
- D. Five or six, depending on which block moves
Why C is correct
NAVEDTRA 14343 §8-2 states that a luff tackle, consisting of a double block and a single block, gives a mechanical advantage of three or four depending on which block is the moving (load) block. The theoretical mechanical advantage equals the number of parts of the fall supporting the moving block.
Cited:NAVEDTRA 14343 §8-2