Linda Wright Photo

Melges 24

The 75 mm is our largest Ratchamatic®. It is perfect on boats like the Mumm 36, Melges 24 and Melges 32. We also offer a cheek Ratchamatic. They mount on either port or starboard and are available in 57 mm and 75 mm sizes.

Ratchet Blocks Q&A


General Information

Harken Ratchamatic®, Carbo Ratchet, and Hexaratchet® blocks are lightweight, strong, and run exclusively on ball bearings for fast trimming under any load.

Ratchet Sheave

Harken Ratchet Blocks

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

 2160.jpgI 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.

2160_arrow.jpgAny 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.

Ratchet Blocks with Shackles

What are Harken Hexaratchet® and Carbo Ratchet blocks?
Ratchet SwitchesHexaratchets® and Carbo Ratchets have sheaves that turn only in the trimming direction when the ratchet is turned on. Carbo Ratchets are built with the same lightweight and strong materials as other Harken Carbo blocks, while Hexaratchets® come in the stainless steel-reinforced Classic style. Hexaratchets® and Carbo Ratchets increase holding power by as much as 15:1.

What is a Carbo Ratchamatic®?
Carbo RatchamaticThe load-sensing Carbo Ratchamatic® has a ratchet that instantly engages when a predetermined load is reached. When unloaded, the ratchet pawl seamlessly disengages to allow the sheet to run out instantly during mark roundings and jibes. The Ratchamatic allows lightly-loaded sheets to run freely in both directions for fingertip control. The preset load threshold can be fine-tuned with an Allen wrench to suit different applications, sailing styles, and body types.

How do I adjust a Carbo Ratchamatic to engage the ratchet at a higher or lower load?
Carbo RatchamaticTo increase or decrease the load at which the ratchet engages, first, move the sheave so the hole in the sheave’s groove is at the bottom of the block. Insert a 2.5 mm Allen wrench and turn clockwise to engage at higher loads and counterclockwise for lighter loads. You will need to remove the becket before adjusting if it is a becket block.

Carbo RatchamaticThe load on my beach cat's jib is so high I can't hang on to the line. Is there a good way to manage this load?
Many cat sailors rig a 2625 57 mm Carbo Ratchamatic at the normal jib sheet block location and then install a second 2625 57 mm on an eyestrap on the front crossbeam about a third of the way in from the outboard ends. Adjust the Ratchamatic so the ratcheting function engages when you need it.

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