What Is a Boom?

The boom is the horizontal spar attached to the mast by a hinged fitting called the gooseneck, and it carries the foot of the mainsail. It has two identities: a trimming tool and a heavy lump of metal swinging at head height. In an uncontrolled gybe, the arc swept by the boom is one of the most classic injury zones in sailing.

A boom brake or preventer is there for exactly this moment.

Safety and maintenance

• Preventer: on a run, a line led forward to hold the boom in place should be second nature; on a charter or guest cruise, one simple briefing is enough: 'This metal moves, so duck as you pass under it.'

• Gooseneck: any play in the mast-to-boom joint will be heard as a rattle on every passage; pins and bushes are consumable parts.

• Topping lift: if the line supporting the boom when the sail is down is slack, the boom will drop into the cockpit.

A fouled reefing line, or neglected boom sheaves, can make reefing fully stiff; in heavy weather that is the last thing you want. Annual maintenance is a five-minute check of the gooseneck pin and the boom’s internal sheaves.