🔍 Key Concepts
• Count how many sheaves (pulleys) are in the upper and lower blocks of tackle #12.
• Notice where the fall / hauling part comes out (top block or bottom block, toward the load or away from it).
• Recall the standard names for tackles: single whip, gun / gin tackle, luff tackle, twofold and threefold purchases, davit or boat falls, deck tackle.
đź’ Think About
• How many sheaves are in each block in tackle #12, and how does that compare with what you would expect for a threefold purchase?
• Is tackle #12 arranged more like something you would see permanently rigged on a boat davit, or more like a temporary lifting tackle used on deck?
• Which of the listed names is associated with multiple-sheave purchases giving high mechanical advantage versus simpler tackles used just to change direction of pull?
âś… Before You Answer
• Verify the number of sheaves in the upper and lower blocks for tackle #12 and compare with the simpler tackles earlier in the plate.
• Check whether the hauling part leads from the moving block or the fixed block, and whether it leads up or down.
• Match that pattern with the standard textbook definition of a gin tackle, threefold purchase, davit tackle, and deck tackle in your seamanship notes.