In this article, you will learn about the function of the boom on a sailboat and how to jibe in a controlled manner. The boom is a potentially hazardous part of sailing and one of the major reasons why I always recommend taking a good sailing course.
The Function of the Boom:
On a sailboat, the “boom” is typically a horizontal spar that is perpendicular to the mast and keeps the mainsail stretched along the foot (the bottom part of the sail). The boom is an essential component of the rigging, especially on recreational boats.
The boom is secured aft by the mainsheet, and its position relative to the centerline is adjusted using the mainsheet. When the wind is coming from directly behind the boat, the boom should be extended as far as possible. Conversely, when the wind is more forward, the boom is pulled in closer, which in turn adjusts the position of the mainsail.
Properly adjusting the boom is a crucial part of sail trimming on a sailboat. When you trim the boom correctly, you can sail either quickly or comfortably, depending on your preference. For example, if a boat is heeling too much, you can ease the mainsheet to extend the boom, helping the boat stay more level in the water.
Jibing:
Jibing is a maneuver performed on a sailboat.
When jibing, you change the boat’s heading to bring the wind from behind, which involves passing the bow of the boat through the wind. During a jibe, the boom switches sides to allow the sail to catch the wind from the opposite side of the boat.
Controlled Jibing:
Controlled jibing occurs when you bear away from the wind enough for the boat to pass through the eye of the wind. Simultaneously, the helmsperson falls off, and the mainsheet is pulled in. The mainsheet is attached to the boom, so when you pull it, the boom moves toward the centerline. The mainsail is only eased out again when the wind comes from the other side.
Typical commands during a jibe include:
- “Prepare to jibe.”
- “Jibe ho!”
- “We have jibed.”
Commands are particularly important on small boats where the boom is lower than the cockpit level. Everyone should duck before a jibe to avoid contact with the boom.
On racing boats, the person handling the mainsheet may initiate the jibing maneuver.
Warning: Everyone should always stay below the level of the boom when the wind is coming from behind to avoid uncontrolled jibes as described below. Additionally, when moving around on the deck, always stay behind the boom (to leeward).
Another term for jibing is “gybing.”
Uncontrolled Jibing:
Uncontrolled jibing typically occurs when the wind shifts slightly, causing it to come from the other side of the boat.
Uncontrolled jibing can be dangerous because, depending on the wind’s strength, the boom can swing across with significant speed and force. In the worst-case scenario, this could injure or even kill someone or damage the mast. Many people have been swept overboard by an uncontrolled jibe.
See an uncontrolled jibe on YouTube.
Boom Preventer:
A boom preventer or boom brake is a device attached to a line that prevents the boom from switching sides uncontrollably. There are various models available, and you can even make one yourself. Most of them work by slowing down the movement of the boom.
If you want to see a preventer, this model is one of the most common: Boom Brake.