Harken 57 mm Ratchamatic Block – Swivel, Becket, Cam Cleat

Harken 57 mm Ratchamatic Block
Vendor

Sheave Size

Block Type

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Block Model

SKU: HAR 2628 Category: Brand:

$225.95

: $257.10 (12 %)

Harken 57mm Ratchamatic Ratchet Block – Swivel, Becket & Cam Cleat

The Harken 57mm Ratchamatic Block automatically switches between free-running and ratchet modes as loads increase, making trimming easier while still allowing sheets to run freely when unloaded. Ideal for cruising and DIY sailors upgrading mainsheet or jib sheet systems.

Why Sailors Choose This Block

  • Automatically engages ratchet under load
  • Runs freely in light air
  • Adjustable ratchet engagement settings
  • Integrated cam cleat and becket save space
  • Excellent for cockpit trimming positions

Common Uses Onboard

This 57mm Ratchamatic block is commonly used for:

  • Mainsheet systems
  • Jib sheet trimming
  • Traveler control systems
  • Spinnaker sheet control
  • Cockpit trimming upgrades

Typically suited for boats in the 28–40 ft range, depending on loads and system layout.

Is a 57mm Block the Right Size?

Choose a 57mm block when:

  • Sheet loads are moderate to high
  • You are using 8–10mm control lines
  • Extra holding power helps reduce trimming effort

Smaller boats often use 40mm hardware, while larger or high-load systems may require 75mm or larger blocks.

Product Overview

Harken’s Carbo Ratchamatic is a load-sensing ratchet block that rolls freely in both directions under light load and automatically engages the ratchet as loads increase. Engagement is seamless, allowing unloaded sheets to run freely during maneuvers while providing added holding power when trimming under load.

Ratchet engagement levels can be adjusted based on crew strength and sailing style. The 57mm model provides holding power up to 10:1, making trimming easier while maintaining quick release when needed.

Technical Specifications

Sheave Diameter 57 mm (2 1/4 in)
Max Line Diameter 10 mm (3/8 in)
Maximum Working Load 272 kg (600 lb)
Block Type Ratchet with Cam Cleat & Becket
Brand Harken

 

Need Help Upgrading Your System?

Our Annapolis and St. Thomas rigging teams design and install complete running rigging systems for cruising and performance boats. Contact us if you’d like help selecting or installing the right hardware.

Contact The Rigging Company →

Frequently Asked Questions

Why choose a Ratchamatic instead of a standard ratchet block?

A Ratchamatic runs freely in light air and automatically adds holding power when loads increase, reducing trimming effort without sacrificing ease of release.

Can this replace my existing mainsheet block?

In most cases, yes — provided line size and load ratings match your system.

What line size works best?

Most systems use 8–10mm mainsheet or jib sheet lines with this block size.

The Rigging Company
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