USCG Exam PracticeDeck machinery and ground tackle
The theoretical mechanical advantage of a luff tackle is which of the following?
- A. One — it provides only a change of direction
- B. Two or three, depending on which block moves
- ✓ Three or four, depending on which block movesCorrect
- D. Five, because it consists of two double blocks
Why C is correct
A luff tackle, consisting of a double block and a single block, provides a theoretical mechanical advantage of three or four depending on which block is the moving (load) block. A gun tackle (two single blocks) gives two or three; a single whip gives no mechanical advantage.
Cited:NAVEDTRA 14343 §8-2