Block and tackle in the line that either attach to or run through the moving blocks—in other words, the number of supporting rope sections. An ideal block and tackle with a moving block supported by "n" rope sections has the mechanical advantage (MA), where F is the hauling (or input) force and F is the load. Consider the set of pulleys that form the moving block and the parts of the rope that support this block. If there are "n" of these parts of the rope supporting the load "F," then a force balance on the moving block shows that the tension in
Block (sailing) matter is slightly complicated by the fact that every tackle has a "working end" where the final run of rope leaves the last sheave. More mechanical advantage can be obtained if this end is attached to the moving load rather than the fixed end of the tackle. There are various types of blocks that are used in sailing. Some blocks are used to increase mechanical advantage and others are used simply to change the direction of a line. A "ratchet block" turns freely when a line is pulled in one direction but does not turn the other direction, although the