Small boat sailors interested in performance and even simply sailing well know how important it is to be able to feel shifts and changes in wind pressure and respond quickly to them. Harken’s new Zircon blocks deliver that feeling of sensitivity, leading to more precision with your sheets, smoother takedowns, and even, by some accounts, lessening muscle fatigue and thereby boosting time on the water.
The secret is all in the bearings. Trusted Delrin and even Torlon bearings can deform under load. The ceramic (zirconium oxide) bearings and liners in Zircon blocks don’t even flinch at their load ratings. Bearing for bearing, they can handle more compressive load than stainless bearings of the same size (700% more, according to Harken) or titanium and have a smoother, less porous surface for better rolling efficiency.
And since they are so strong, fewer can be used in each bearing to accomplish the goal of better responsiveness. Where there are 50 Delrin ball bearings in a 57mm Carbo Air block, the Zircon blocks use only eight. Not only does this support building an affordable block (zirconium oxide isn’t inexpensive), but the bearings can be spaced in a cage such that one cannot bind on another. The result: even less friction.
They’re not for every application though. The current range of Zircon blocks are designed to replace blocks that manage hand-held lines. This covers nearly everything on a dinghy or small boat, as well as light air applications or the end of cascades on bigger boats. The tradeoff with ceramic’s strength is brittleness. So, Harken has over-spec’d these blocks to avoid any issues with shock loading. In engineering terms (like all Harken blocks), they have applied a large factor of safety. Don’t let the load rating throw you, though. Yes, it comes in at about half of the Carbo Air blocks, but when was the last time you tried to fight off nearly 800 pounds on a single block by hand? The 330-pound rating on the Zircon block should be plenty, just be conscious within your purchase systems.
Harken began adopting this technology ahead of the Rio Olympic Games, eight years ago. The goal was to create a better mainsheet for the Nacra 17 class, at the request of Bora Gulari. The efficiency gained enabled a more responsive 10:1 with the same loading as the old 12:1. Further refining of the manufacturing process, and with plenty of testing on E Scows, A-Cats, and Moths, and Harken has delivered a cost-competitive ceramic block to the market.
Complementing their other block lines, Harken’s 40mm and 57mm Zircon blocks are available now in singles and doubles (with and without beckets), with the hint of other sizes if the sailing community asks for more.