57mm Block — Swivel, Cam Cleat

Harken 57mm Block — Swivel, Cam Cleat

The Harken 57mm Block — Swivel, Cam Cleat is a high-performance Carbo Air pulley engineered for sailors and sportfishing applications that demand lightweight, strong, and reliable line management. Part of Harken's trusted Carbo Air block line, which is 60% stronger and 30% lighter than conventional designs, this block combines a smooth-running ball-bearing sheave with an integrated cam cleat system for fast, secure line adjustment under load.

The block features two adjustable stainless steel cam arms and an integral aluminum cam cleat based on the Harken 150 Cam-Matic design. Cam arm locking plates allow the cam arms to be set in more than five positions for optimized fair leads. The 3-way cam lock provides versatile positioning: with the cam lever up, the block locks in the front or side position; with the cam lever down, the block rotates freely as a standard swivel block. This flexibility makes it equally effective for fixed-lead and free-swiveling applications.

Constructed from UV-stabilized fiber-reinforced composite materials, the sheave, sideplates, and ball bearings are built to withstand extended exposure to harsh marine environments. The 5 mm stainless steel shackle pin provides a secure, corrosion-resistant attachment point. These pulleys are used in Rupp removable dredge retrieval systems and are well-suited for a wide range of sailboat and sportfishing control line applications including mainsheet fine-tuning, outhauls, cunninghams, vangs, jib sheets, and spinnaker sheets on dinghies, sportboats, and larger vessels.

Key Features

• Low-friction Carbo Air ball-bearing sheave for smooth, efficient line travel
• Two adjustable stainless cam arms with locking plates — lockable in more than five positions
• Integral aluminum cam cleat based on Harken 150 Cam-Matic design
• 3-way cam lock: lever up locks block in front or side position; lever down allows free rotation
• UV-stabilized fiber-reinforced composite construction
• 57 mm (2-1/4 in) sheave diameter accommodates lines up to 10 mm (3/8 in)
• Maximum working load: 300 lb (136 kg); breaking load: 750 lb (340 kg)
• Compact design: 110 mm (4-5/16 in) length; weighs only 269 g (9.5 oz)
• 5 mm (3/16 in) stainless steel shackle pin for secure attachment
• Used in Rupp removable dredge retrieval systems