Harken's Carbo Air Blocks are the modern classic of sailing hardware: injection-moulded from long-glass nylon, they're dramatically lighter than metal-shell blocks yet handle impressive working loads, with free-rolling ball bearings that keep control lines running under load. This collection covers the Carbo range in 29mm, 40mm, 57mm and 75mm sheave sizes - singles, doubles, triples, fiddles and versions with beckets, swivels and cam cleats.
Sized correctly, a Carbo block suits everything from dinghy control lines to keelboat mainsheets. Match the sheave size to your line diameter, check the safe working load against the loads in your system, and choose the head fitting - shackle, swivel or soft attach - that lets the block align with the load. As a UK Harken stockist we can help you spec a complete purchase system.
Frequently asked questions
What line sizes do Harken Carbo blocks take?
As a guide: 29mm blocks suit lines up to 8mm, 40mm up to 10mm, 57mm up to 12mm and 75mm up to 14mm - always check the specific block's stated maximum line diameter and working load.
Are Harken Carbo blocks strong enough for a keelboat?
Yes - despite their light weight, Carbo blocks carry high safe working loads for their size, and the 57mm and 75mm sizes are widely used for keelboat mainsheets, vangs and control systems.
What is the difference between Carbo and Carbo Air T2 blocks?
Standard Carbo blocks use a shackle or swivel head, while T2 soft-attach versions lash directly to fittings with high-strength line - lighter and quieter, and ideal for high-tech rope systems.
