As with traditional blocks, the ratchet blocks comes in several versions. Its particularity lies in the fact that its rotation can be limited to one direction only when slacking sheets by engaging a locking pawl.
The ratchet block is often the last in a series of fittings, facilitating line control.
The ratchet block can be single, double or even triple, and can be mounted on a swivel with a cleat. It has two distinguishing features. Its sheave is toothed rather than smooth to better hold the line passing through it. An internal mechanism can be engaged to prevent the sheave from turning in one direction. For example, it may turn freely when sheeting in and block when slacking off. When the mechanism is disengaged, the sheave can turn freely in both directions. Some models engage automatically in response to pressure on the sheave.
Choice of ratchet block will depend on intended use, necessary purchase, line diameter and stress.
