57 mm Carbo Ratchamatic Block Swivel – Harken

The Harken 57 mm Carbo Ratchamatic block with swivel gives you grip when you load up and free running when you ease, without ever touching a switch.

The Ratchamatic mechanism senses load and engages the ratchet automatically. In light air the sheave spins freely so the sheet runs out cleanly, and as the load builds the ratchet engages to hold the line and take weight off your hand. When the load drops again it releases on its own, so there is no on/off switch to manage mid-manoeuvre.

With a 57 mm sheave, a swivel head and a maximum line diameter of 10 mm, it suits mainsheet and control systems on dinghies and sportboats where load changes constantly through the day. The 227 kg working load covers hand-held trimming positions where smooth, automatic grip matters more than maximum load.