Harken 75mm Carbo Fiddle Ratchet Block with Becket and Cam allows for 3:1 or 4:1 tackles on dinghy vangs and mainsheets.
Carbo Ratchets 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 75mm fiddle blocks are for vang systems on larger to medium-sized dinghies or keelboats.
The 40mm, 57mm, and 75mm Carbo Ratchamatic® are adjustable for many applications and weather conditions. The load-sensing ratchet block rolls freely in both directions under low loads and then engages the ratchet automatically as loads increase. With a 180-degree wrap, you get a 10:1 holding power.