Ronstan Series 50 Single Stand-Up Sailing Block

The Ronstan Series 50 Single Stand-Up Sailing Block is an all-purpose block for mainsheets, halyards, vangs, and spinnaker-control lines that need to rise cleanly from a deck or other fixed surface. The stand-up arrangement holds the block in a useful position while still allowing it to move as the line lead changes. That makes it easier for the rope to find the sheave than a block that simply falls flat when the system is unloaded. The Series 50 construction is aimed at dependable service on cruising and racing sailboats rather than minimum-weight hardware alone.

A self-lubricating Acetal sheave provides low-maintenance rotation, and the main load strap is Grade 316 stainless steel for corrosion resistance. Impact- and UV-resistant fiber-reinforced nylon cheeks protect the sheave while keeping the assembly lighter than an all-metal housing. Ronstan's Captive Lock universal head is designed to keep the attachment controlled while still giving the block room to articulate. The materials are well suited to deck hardware that moves between dry storage, spray, and repeated saltwater exposure.

• Stand-up format keeps the block ready for the line
• Self-lubricating Acetal sheave
• Grade 316 stainless-steel load strap
• Captive Lock universal head

Allow enough space around the stand-up base for the block to move without hitting the deck, fasteners, or adjacent fittings. The mounting structure, line, and attachment hardware should all be sized for the loads in the completed purchase. Rinse the sheave and articulation point after saltwater use and check for free movement before the next hard sail. For additional stand-up blocks and general sailboat rigging hardware, browse more Sailing Hardware.