Self Aligning Mainsheet Jammer

Central mainsheet jammers are an important bit of kit. They don’t feature on all types of boats, but when they are used it’s because they play a vital role in helping the helm or crew. Be it with manoeuvres or freeing up a hand to pull something else. Those that have sailed a single-handed trapeze boat, will know especially well how important they are.

However, most people who have sailed a dinghy or keelboat with a centre-mounted mainsheet jammer will have come across the issue of the mainsheet jammer not rotating to the correct orientation after a tack or gybe and causing the mainsheet to get wrapped or twisted. It’s extremely annoying, and in a worst-case scenario can lead to a capsize or broach.

We wanted to solve this issue, so we did!

Our self-aligning mainsheet jammer – A5266 – is the only one of its type available on the market. It offers hands-free turning of the jammer through tacks and gybes, reducing the chance of mainsheet wrappage and allowing you to keep a hand free through a tack or gybe – perfect for trapezing boats.

The self-aligning mainsheet jammer works by having the ratchet block mounted to a small arm which is set off to one side of the central swivel point.

Moving the block outward from the swivel point and angeling the bottom of the block away from the cam cleat creates a turning force on the block. Meaning the cam cleat will always be forced to point away from the leeward side of the boat. This also helps prevent the mainsheet from wrapping around the block and allows the user to free their hand which can lead to smoother tacks and gybes.

The self-aligning mainsheet jammer is available in two sizes:

Standard height – 148mm high x 234mm long.

Compact – 117mm high x 197mm long.

Both versions are also available with or without our 60mm Pro-Ratchet block. However, for best results, we recommend sticking with the 60mm Pro-Ratchet, as the angles have been designed specifically with this block in mind.

The swivel arm features our cold forged bearing system which has a ball-locating groove for smooth rotation, whilst preventing the lateral movement of the arm.

The arm can be set to rotate at 180, 220 or 360 degrees by adjusting the stopper pins on the underside of the arm.