Harken 40mm Zircon Block
The Harken 40mm Zircon Block combines Harken's most advanced ceramic bearing technology with a larger, higher-capacity platform, making it the ideal choice for performance yachts, sportsboats and larger dinghies where control line loads are higher but friction must remain as low as possible. Designed for sailors who demand the highest level of efficiency, it delivers exceptionally smooth operation and immediate response under load.
At the heart of the block are industrial ceramic ball bearings running within precision caged races. Unlike conventional loose bearing arrangements, the caged design keeps each bearing perfectly separated, preventing them from bunching together as loads change. This allows the sheave to rotate with exceptionally low start-up friction, resulting in smoother trimming, greater sensitivity and more accurate sail control, particularly during continuous adjustments and in lighter conditions where every reduction in friction is noticeable.
The ceramic bearings provide outstanding resistance to compression, enabling the block to retain its free-running characteristics through repeated loading. Combined with Harken's precision-engineered sheave and bearing race design, the Zircon range represents the highest-performance small block family in Harken's portfolio, delivering measurable gains in efficiency over conventional ball bearing blocks.
With a Safe Working Load of 115kg and a maximum recommended rope diameter of 8mm, the 40mm Zircon Block is well suited to a wide variety of control line applications on performance sailing yachts. Typical uses include mainsheet fine-tune systems, vang controls, traveller controls, cunninghams, outhauls, barber haulers, backstay cascades and other trimming systems where smooth, low-friction operation improves both handling and sail shape.
The lightweight soft-attachment head allows the block to align naturally with the direction of load, reducing side loading while keeping weight to a minimum. The larger 40mm sheave also offers improved rope support and lower bending loads compared with smaller blocks, making it particularly suitable for higher-load control systems using up to 8mm line.
The 40mm Zircon family includes single, single with becket, double, double with becket, triple and triple with becket variants, allowing complete low-friction purchase systems to be assembled using matching blocks with identical ceramic bearing technology and consistent performance throughout.
For sailors seeking premium performance from every control line, the Harken 40mm Zircon Block delivers exceptional efficiency, precise handling and the smooth, responsive feel that distinguishes Harken's flagship Zircon range.
and then Add to Home Screen.
