Ronstan Series 20 Triple Becket Ball Bearing Block

The Ronstan Series 20 Triple Becket Ball Bearing Block is a compact choice for dinghy vangs, cunninghams, traveler controls, and other small-boat purchases that need three sheaves in one head. Its becket gives the standing end a dedicated attachment point, so a multi-part purchase can be built without adding another fitting. The shackle head can be fixed at either 0 or 90 degrees, which helps the installer line the block up with the direction of pull. That combination keeps a surprisingly capable purchase system tidy in places where deck space and weight are limited.

Precision-molded Acetal sheaves run on stainless-steel or Torlon ball bearings to reduce friction during frequent adjustment. Grade 316 stainless steel carries the main load through the strap and head fitting, while fiber-reinforced nylon cheeks provide impact and UV resistance. The block is intended for both dynamic trimming and sustained static load, rather than being a lightly built fairlead. Its compact bearing package also makes routine rinsing and inspection straightforward after saltwater use.

• Triple-sheave layout with integrated becket
• Two-way head can be fixed at 0 or 90 degrees
• Acetal sheaves on low-friction ball bearings
• Grade 316 stainless-steel load hardware

Ronstan specifies line up to 6mm (1/4 in), a maximum working load of 880 lb, and a 1,870 lb breaking load for this model. At about 2.3 oz, it adds little weight to a dinghy control system even when used in a multi-part purchase. Choose the reeving and attachment orientation before installation so all three sheaves share the load cleanly. For more dinghy blocks and purchase-system components, browse more Sailing Hardware.