Ronstan RF51140 Series 50 All Purpose Single Stand Up Block

The Ronstan Series 50 All Purpose Block is a versatile single block with stand-up configuration, designed for mainsheet, halyard, vang, and spinnaker control line applications on boats up to 10m (33ft). Built for both cruising and racing, this block delivers exceptionally high working loads with low maintenance and long service life.

Key Features:

• Self-lubricating Acetal polymer sheave on polished stainless steel races for low friction and extreme durability
• Captive Lock™ universal head can be fixed in two planes or swivel freely as required
• Slotted pin shackle design prevents fouled lines
• Quick-adjusting cleat arms with no tools required for adjustment
• Removable becket pin allows line to be spliced before fitting
• Mounts with 2 x 5mm (3/16") fasteners (not supplied)

Construction:

• Grade 316 stainless steel load strap for maximum strength and corrosion resistance
• Impact and UV resistant fiber-reinforced Nylon cheeks

Applications:

• Ideal for direct 4:1 purchase systems such as mainsheets and boom vangs
• Mainsheet and halyard systems, vang and spinnaker control lines
• On larger boats: fine-tune mainsheet tackles, outhauls, cunninghams, checkstays, genoa lead pullers, and traveller controls

These all-purpose blocks perform equally well under dynamic loads and high static loads, making them the right choice for sheets, halyards, and control line applications across a wide range of sailing conditions.