Harken 57mm Low Load Double Block – Black Magic Air (3228)
Dual-sheave efficiency for low-load sail control systems
The Harken 57mm Low Load Double Block (3228) is part of the Black Magic® Air series, optimised for applications where smooth performance and weight savings are key, but full high-load ratings aren’t necessary. Designed for mainsheets, halyards, runners, and spinnaker systems on big boats, this double-sheave version delivers excellent purchase and line handling in moderate-load setups.
It features Torlon® roller bearings supported by a centre cage that keeps the rollers aligned and separated, reducing friction and ensuring free-running movement under load. As with all low-load variants in the series, it is marked by red isolators and equipped with a 316 stainless steel shackle, distinguishing it from the high-load counterparts which use 17-4 PH stainless headposts.
The shackle head can swivel or be locked in two fixed positions, giving riggers flexible mounting options while helping to maintain fairleads and reduce line twist. Hard Lube-anodised sideplates and sheaves offer superior resistance to UV and wear for long-lasting performance.
Specifications
| Length (mm) | 132 |
| Recommended line - Max Ø (mm) | 12 |
| Sheave Ø (mm) | 57 |
| SWL (kg) | 1250 |
| NBL (kg) | 2500 |
| Weight (g) | 342 |
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