A snatch block is a sheave in a side-opening frame — the tool that lets you redirect a winch or hoist line mid-span without re-reeving, or double a line for twice the pull at half the speed. Simple hardware, but the loads it sees are anything but obvious: the block's load depends on the angle of the line around it, and riggers who skip that math overload blocks constantly.

The Angle Math Every User Needs

When a line turns through a block, the block feels the resultant of both line legs:

A 10,000-lb winch line doubled 180° through a block puts 20,000 lb on that block and its anchor. Size the block — and the shackle and anchor point behind it — for the resultant, not the line pull.

Sheave Size & Rope Life

Sheave diameter drives rope fatigue: the smaller the D/d ratio, the faster the rope dies. Field target: sheave tread diameter at least 12–16× rope diameter for running lines; never run rope through a block whose groove doesn't match the rope size (too small pinches, too large flattens).

Configurations

Hook-end blocks connect fast to lifting points; shackle-end blocks make a more secure semi-permanent connection; tailboard blocks mount to flat surfaces. Latch hooks are the minimum for any overhead use. Capacities run from 1-ton utility blocks through 30+ ton construction blocks — see our snatch block collection.

Working Rules

Stay out of the bight — the inside angle of a loaded redirected line is a kill zone if anything parts. Close and secure the side plate before loading, seat the rope in the groove, lubricate the sheave bearing on schedule, and inspect for cracked side plates, wobbling or grooved-out sheaves, spread hooks, and bent pins.

Blocks Sized to Your Line

Snatch blocks across the capacity range with hook or shackle ends. Line size, line pull, and angle into the quote form at the top of the page — we'll confirm the resultant load and quote during business hours.