Seldén plain bearing blocks (PBB) in 16 mm, 20 mm and 40 mm sheave sizes for static and heavy loads on dinghy halyard systems, boom vangs and kicker tackles where slow line movement and high load capacity matter more than friction.
How to choose
Plain bearing blocks use a polymer bushing rather than ball bearings. This makes them better suited to heavy, slow-moving or static loads where the line moves infrequently and sustained load capacity is the priority. Typical applications are boom vangs, kicker tackles, halyard tuning systems and other controls that are adjusted occasionally and then held under high load. For dynamic applications where the line runs frequently, a ball bearing block from the BBB range will give significantly less friction.
The 16 mm and 20 mm plain bearing blocks are the lightest option in the range, suited to flag lines, lazy jacks and very light trim lines where load is minimal and simplicity matters. The 20 mm flip-flop is a specific variant designed for dinghy trim lines including cunningham, outhaul and halyard where a compact, low-profile fitting is needed.
The 40 mm plain bearing blocks handle lines up to 8 mm under heavy or static loads. They suit halyard tuning, mainsheet systems where load is high and movement is infrequent, and boom vang applications. The polymer sheave and stiff glass fibre reinforced cheeks prevent line jamming under sustained load. The fiddle swivel variant combines a large and small sheave in one block body, providing a built-in purchase ratio in a compact unit.
What's in this collection
The PBB16 range is available in composite (401-001-01) and brass (401-001-02) versions, both suited to flag lines, lazy jacks and similar light applications on lines up to 6 mm.
The PBB20 range includes a standard single (402-001-01) for flag lines and lazy jacks up to 6 mm, and the flip-flop variant (402-001-02) designed for dinghy trim lines including cunningham, outhaul and halyard.
The PBB40 range covers lines up to 8 mm for heavy and static load applications. Available as swivel (404-001-01R), swivel becket (404-001-02R), strap (404-001-25R) and fiddle swivel (404-001-11R). All have polymer sheaves with stiff glass fibre reinforced cheeks. The swivel variants include a swivel lock for fixed 0° or 90° shackle position.
