Block Opti Sheet Ratchet 57mm by Harken
Harken 57mm carbo ratchet block. Machined aluminium sheave with 8 facets to hold the line securly. Weight only 85 grams
Harken Ratchamatic®, Carbo Ratchet, and Hexaratchet® blocks are lightweight, strong, and run exclusively on ball bearings for fast trimming under any load.
What are Harken ratchet blocks?
Harken ratchet blocks hold part of the sheet’s load, let you trim and ease with complete control, and enable higher trimming speeds. Ratchets make it much easier to hand-hold higher loads by only allowing the sheave to turn in the trimming direction. When you are holding or releasing the load, the faceted sheave grips the line to reduce fatigue and give you more control. Also, ratchets make faster trimming possible because you don’t have to hold the full force of the sheet while shifting your grip.
Options include ratchet blocks with beckets, adjustable cams, multiple sheaves, adjustable automatic load-sensing mechanisms, and footblock and fiddle configurations. Harken offers ratchet blocks in sizes between 40 and 75 mm (1 9/16"–3").
Where should I use ratchet blocks?
Ratchet blocks are great for any system that is normally adjusted by hand, including mainsheets, jib sheets, spinnakers, vangs, and backstays on everything from dinghies to large keelboats. In addition to increasing the loads you can manage without a winch, they reduce shock loading on your hands and your equipment—for example, a ratchet block can stop an unanticipated gust from yanking the line through your hands or from putting too much load on your cam cleats. Some dinghies and sportboats even use two Ratchamatic blocks in series for turns less than 90 degrees per ratchet block.
T2™ Soft-Attach Ratchamatic® Blocks
I race a sportboat and am looking for a lightweight auto-ratchet from my spinnaker and mainsheet systems. What do you recommend?
We developed our soft-attach Ratchamatic especially for spinnaker and mainsheet systems on sportboats as well as dinghies and beachcats. Like its shackled predecessor, our auto ratchet has composite sideplates and a hardcoat-anodized sheave. But in this version, we reduced components by 50% and added a soft-attach. The result is a strong, free-running block that weighs only a few ounces.
How about holding power?
You can count on the Ratchamatic’s powerful sheave geometry to hold your sheet securely, but still provide great trimming ″feel″. Plus, you won’t tear up your sheet playing the shifts in a blow.
How do you fasten soft-attach Ratchamatics?
Just like our popular T2 series of blocks, you may lash or splice them on through the block’s strong load-bearing center. This decreases the loads on the sideplates and acts as a safety backup for the system.
Any other advantages?
Absolutely. Lashing secures the block close to the deck and keeps it from capsizing.
What’s the deal with the arrows on the sideplate?
The high-contrast arrow on the side of the block shows the direction the sheave will spin in ratchet mode. This is really helpful when reeving the block as well as indicating which side of the block to pull for trimming after a mark rounding.