Harken 75mm Black Magic Air Runner Block
Low-friction strength for high-load 2:1 runner systems
The Harken 75mm Black Magic Air Runner Block is purpose-built for standard 2:1 running backstay systems, where high load, smooth rotation, and reliability are essential. Designed for 14mm lines and rated to a Safe Working Load (SWL) of 2268kg, this block is a go-to solution for performance yachts operating under demanding trim conditions.
Built for the Load – and the Long Haul
With its 75mm Torlon® roller bearing sheave, this block delivers outstanding efficiency under constant or shock load. The internal centre cage keeps the bearings evenly spaced and aligned, reducing friction and increasing longevity. Delrin® ball bearings manage side loads and are fully captive, making on-board maintenance straightforward and risk-free.
Ideal for 2:1 Runner Configurations
Whether on a fixed backstay with a flying runner, or as part of a cascaded system, this block is designed to handle the dynamic, high-frequency adjustments that runner applications demand. Its robust construction and low-friction design ensure fast, precise response every time the runner is trimmed or released.
Sailor-Friendly Serviceability
The Black Magic range is engineered with practical maintenance in mind: fasteners (not rivets) allow for easy disassembly using a single hex wrench. With no loose rollers or bearings, cleaning and servicing is fast and secure, even during offshore campaigns.
Tough, Lightweight Design
Constructed with hardcoat anodised aluminium side plates, the block maintains an impressive strength-to-weight ratio while resisting corrosion and UV degradation. The rugged black finish stands up to the elements while keeping your deck gear looking sharp.
Specifications:
- Sheave Diameter: 75mm
- Maximum Line Diameter: 14mm
- Safe Working Load (SWL): 2268kg
- Breaking Load: 4536kg
- Configuration: Runner Block (2:1 system)
For high-performance boats relying on precision runner tension, the Harken 75mm Black Magic Air Runner Block offers dependable power, minimal friction, and race-proven durability—perfect for both inshore grand prix and offshore racing environments.
Specifications
| Length (mm) | 118 |
| Recommended line - Max Ø (mm) | 14 |
| Sheave Ø (mm) | 75 |
| Pin Ø (mm) | 12.7 |
| SWL (kg) | 2268 |
| NBL (kg) | 4536 |
| Weight (g) | 288 |
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