Ronstan RF51530 Series 50 Fiddle Block with Becket and Cleat

The Ronstan Series 50 All Purpose Block is a high-performance fiddle block featuring an integrated becket and adjustable cleat, designed for mainsheet, halyard, and control line applications on sailboats up to 10m (33ft). This versatile block combines exceptional working loads with low-friction performance for both cruising and racing applications.

Key Features:

• Self-lubricating Acetal polymer sheaves running on polished stainless steel races for low friction and extreme durability
• Captive Lock™ universal head can be fixed in either of two planes or left free to swivel as needed
• Quick-adjusting multi-position cleat arm requires no tools and fixes securely in position
• Slotted pin shackle design eliminates fouled lines
• Snap-fit removable becket pin allows line to be spliced prior to fitting
• Exceptionally high working loads with low maintenance requirements

Construction:

• Grade 316 stainless steel load strap for maximum strength
• Impact and UV resistant, fiber-reinforced Nylon cheeks
• Self-lubricating components ensure long service life

Applications:

• Mainsheet and halyard systems on boats to 10m (33ft)
• Vang and spinnaker control lines
• Fine-tune mainsheet tackles, cunninghams, and backstays
• Control line purchase systems for cruising and racing

Replacement parts available: RF51010 Becket Pin and RF150 Shackle. The fiddle block configuration provides a 2:1 mechanical advantage while the integrated cleat allows for secure line holding without additional hardware.