Ronstan Series 25 High-Load Lashing Orbit Block

The Ronstan Series 25 High-Load Lashing Orbit Block is a compact single-sheave block for modern dinghy and small-boat controls that use high-strength line and soft attachments. Its lashing head reduces metal hardware at the attachment point and lets the block articulate naturally within a lightweight control system. Ronstan developed this high-load version for mainsheet and spinnaker turning points, cunninghams, cascading vangs, and other controls where small-diameter line carries serious load. The hollow hub can also be used for a becket take-off, adding flexibility without increasing the size of the block.

Unlike the standard Series 25 version, the high-load model uses a Grade 2205 stainless-steel sheave and bearing race with Grade 304 stainless-steel ball bearings. The frame and cheeks are toughened glass-fiber reinforced nylon, keeping the body light around the metal high-load core. Ronstan's two-stage bearing concept supports easy movement while maintaining strength as the load climbs. The lashing hub accepts soft attachment material up to 4mm (5/32 in), making the block well suited to current performance and foiling-boat rigging practice.

• High-load stainless-steel sheave and bearing race
• Two-stage ball-bearing system
• Hollow hub supports becket take-off
• Lashing attachment accepts up to 4mm line

The block is designed for control line up to 8mm (5/16 in) and is aimed at high-load systems on dinghies up to about 4m. A soft lashing should be sized, reeved, and protected from chafe for the load carried by the complete system. Check both the stainless bearing components and the lashing for wear during routine rigging inspections, especially on foiling or highly loaded boats. For more compact high-load blocks and dinghy rigging components, browse more Sailing Hardware.