Boom preventer

Introduction.

One of the most dangerous situations aboard a sailboat is an unintentional gybe. An unintenional gybe is a sudden, sharp turn of the mainsail, meaning the sail shifts to the other side of the sail on the tack, causing the wind to pass behind.

The boom, in the violent and uncontrolled movement that occurs during an unintentional gybe, can cause serious injuries to a crew member, from a severe blow to the head or even fall overboard.

An unintentional gybe usually happens when sailing with the apparent wind astern and, suddenly, with a change of course or a wind shift, the wind blows forcefully on the opposite side of the sail (from further forward of the boom), causing it to gybe.

A boom preventer (or boom stopper) is a piece of equipment designed to prevent this unintentional gybe. We may not be able to prevent the boat from turning completely around, but we will avoid the damage caused by the involuntary movement of the boom.

On the other hand, the stresses and strains to which this retaining rig can be subjected are very significant; therefore, it must be properly sized. It is common to see ineffective or broken retaining rigs.

Next, in this new chapter of the online book “Sail Handling and Trimming,” we will look at some simple considerations regarding the use of the preventer on a cruising sailboat, which can help us improve safety on board.