Harken 57mm Carbo Ratchet Block with Becket allows either a 2:1 or 3:1 purchase.
Carbo Ratchet blocks allow sailors to hand-hold loaded lines and offer a balance between holding power and controlled easing. Lightweight Carbo Ratchets are available in 40mm, 57mm, and 75mm sizes. All the Carbo Ratchets feature a recessed On-Off switch that is easily operated from either side. The 40mm cam-arm versions work in ratchet mode only. Commonly 57mm blocks are for jibsheets and spinnakers on medium sized dinghies.
The 40mm, 57mm and 75mm Carbo Ratchamatic® is adjustable for many applications and weather conditions. The load-sensing ratchet block rolls freely in both directions under low loads, then engages the ratchet automatically as loads increase. With a 180-degree wrap, you get a 10:1 holding power.
Hand-hold your loaded lines
Use for spinnaker sheet systems on dinghies, sportsboats, and medium keelboats
Ratchet blocks are hand and crew savers
Allows a line to be eased instantly with control
On/Off switch allows the ratchet to be turned off in light air