Boom Control and Gybe Preventer System

The Jimmy Green Boom Control and Gybe Preventer System comes in four sizes with set lengths specified according to approximate boom length.

Please enquire if you need any slight alterations to the kit contents.

Boom Preventers can be rigged to prevent an accidental gybe, commonly referred to as a Chinese Gybe.

Boom Preventer General Objectives:

• to mitigate sudden boom movements caused by wind gusts or manoeuvring
• to reduce crew strain during heavy weather sailing
• to minimise the risk of injury from an uncontrolled boom swinging across the centre line

Jimmy Green Boom Control and Gybe Preventer Setup Guide:

• Fasten the pennant to the end of the boom with the soft shackle provided
• Boom end attachment point - to the underside of the boom for a single preventer, to the port and starboard side for twin preventers
• Connect the pennant to the shock cord with the hook provided.
• Stretch the shock cord towards the mast and secure it to an anchor point
• Select a fixing point at a distance that will provide the necessary tension to keep the pennant neatly stowed while not in use, preferably without frapping :-) For example, to the top of the vang, to the gooseneck, or around the mast and back to itself.
• Attach a Low Friction Ring to, e.g. the toe rail as far forward as practicable, creating a fairlead with as shallow an angle as possible from the boom end when the mainsheet is fully eased.
• Attach the other Low Friction Ring, further aft to help lead the control line back to the winch.
• Reeve the control line through the Low Friction Rings with the snap shackle end ready to attach to the pennant, and lead the tail back aft to a strongpoint within reach of the cockpit, e.g. a cleat or a clutch

The Set Length options assume that the pennant forward end should be between 0.25 and 1.25 metres from the mast.

This ensures that the shock cord tensioner can be set up to keep the pennant neatly stowed along the boom, ready for deployment.

Jimmy Green Boom Control and Gybe Preventer Sizing Advisory:

Boom lengths can vary quite substantially between yachts of a similar length, so these sizes are an educated guess.

If your boom and yacht length don't reasonably match our estimation, you can easily order these parts separately on our website to create your own bespoke setup.

There is a list of links to the individual products further down the page.

Each Jimmy Green Boom Control and Gybe Preventer System is produced to order, so if you need a simple tweak to an existing size, please ask the Rigging Team if they can accommodate that amendment.

Jimmy Green Boom Control and Gybe Preventer Approximate Size Guide:

Size 1 = For Boom Lengths up to 3 metres and an estimated boat length of up to 10 metres

Size 2 = For Boom Lengths 3 - 4 metres and an estimated boat length of 10 - 12 metres

Size 3 = For Boom Lengths 3.5 - 4.5 metres and an estimated boat length of 12 - 14 metres

Size 4 = For Boom Lengths 4 - 5 metres and an estimated boat length of 14 - 16 metres

Each Jimmy Green Boom Control and Gybe Preventer System contains:

• 1 x LIROS D Pro 12-strand Dyneema Pennant with small soft eye splices on both ends
• 1 x LIROS Braid on Braid EVO Control Line, with a snap shackle soft eye spliced on one end and a whipping on the other end
• 1 x Marlow Soft Shackle
• 1 x length of Shock Cord with a suitable nylon hook
• 2 x Jimmy Green/Barton Low-Friction Rings

Dyneema Pennants

Control Lines

Soft Shackles

Shock Cord and Hooks