SeaSure 25mm Treble Block w/V-Jam

The SeaSure 25mm Treble Block w/V-Jam is a marine-grade rigging block built for serious sailors and boaters who demand reliability in mission-critical applications. Whether you're managing sheet loads on a racing sailboat, setting up halyards on a cruising vessel, or running tackle systems on a commercial fishing boat, this block delivers the smooth, efficient performance that decades of SeaSure engineering have perfected. The 25mm plain bearing block range is one of SeaSure's oldest and best-selling designs, trusted by professional mariners and weekend cruisers alike who understand that when you're on the water, your rigging cannot fail.

Built with marine-grade stainless steel side plates and rivets, the SeaSure 25mm Treble Block resists corrosion and salt-spray deterioration—critical for systems exposed to harsh ocean environments. The arnite (plastic) sheave is exceptionally hard-wearing and light, reducing overall system weight while maintaining superior load distribution and mechanical advantage. The V-Jam feature locks the line securely in place, preventing slippage under load and eliminating the need for knots in high-stress scenarios. This combination of materials and engineering creates a block that operates silently, reduces friction losses, and maintains consistent performance across thousands of load cycles.

This block is ideal for both standing and running rigging applications on displacement cruisers, racing yachts, and commercial vessels where weight savings and corrosion resistance matter. The 25mm size strikes a balance between line capacity and compact footprint, making it perfect for mid-range sheet systems, preventer tackles, and outhaul setups. Installation is straightforward—simply secure the block using existing stainless fittings or shackles compatible with standard block attachment points. At just 1 pound, the SeaSure 25mm Treble Block minimizes aloft weight without compromising the load-carrying capability your vessel demands.