Harken 40 mm Carbo Double Swivel Block 2638Harken 40 mm Carbo Air Double Swivel Block (2638) HighLoad Twin Sheave with 360 Swivel Upgrade your sail control setup with the Harken 2638, a premium grade, lightweight doublesheave pulley tailored for main jib sheets, vang fine tune, outhauls, and high load control systems on dinghies, skiffs, sportboats, and small keelboats. Made using Harkens open Carbo Air design, it combines lightweight Carbon composite side cheeks with dual 40 mm Delrin sheaves

Breaking Load: 700kg

Engineered for high-performance skiffs

Suitable for boats up to 4m (15ft)

UV-stabilised for marine and outdoor use

Part of the Ronstan Series 50 range

With a powerful self‑priming pump

Long coastal passages

low-glare colours to reduce reflection and enhance safety on board

Ideal basecoat for antifoul applications

Track mode

✅ Crevice‑free

max line 10 mm (3/8″)