Allen 40mm Blocks

Allen 40mm blocks are sheet blocks, used where the rope is thicker and the loads are higher than in a control system. Typical uses are mainsheet, jib sheet and spinnaker sheet systems on dinghies and small keelboats. The range includes swivel, cheek, fiddle, becket, snatch and ratchet versions, so a complete sheet system can be built from one family of blocks.

The Allen 40mm Pro Ratchet block grips the sheet when it is under load, taking much of the strain off your hands, yet lets the rope run freely when you ease. That makes it ideal for mainsheets, jib sheets and spinnaker sheets that are held for long periods. The aluminium sheave gives a firm grip on the rope and stands up well to wear.

Choose a swivel block when the rope arrives from changing angles, such as a mainsheet or jib sheet lead, because the head rotates to keep the sheave aligned with the load. Choose a fixed head block when the block should hold its position, which helps stop a multi part purchase from twisting. Many sheet systems use a mix of both.

A fiddle block has a second, smaller sheave mounted in line with the first, which adds purchase while keeping the block slim. A becket is a fixing point on the block where the end of the rope is tied off. Used together, they let you build compact multi part purchase systems for mainsheets and kickers.

Allen 40mm blocks are designed for ropes up to 10mm in diameter. They suit the 6mm to 10mm sheets used for mainsheets, jib sheets and spinnaker sheets on dinghies and small keelboats. Always check the maximum rope diameter and working load on the individual product page before you buy.