Glossary

Deutsch: Niederholer / Español: Preventor / Português: Amantilho / Français: Amure de Sécurité / Italiano: Amantiglio

In the maritime context, a preventer is a safety device used on sailing vessels to prevent the unintended movement of the boom or other spars, especially during heavy winds or when sailing downwind. It is a line or tackle rigged to control the boom and prevent it from swinging violently from one side to the other, which is known as an accidental jibe. This helps to protect the rigging, sails, and crew from potential damage or injury.

General Description

A preventer is typically rigged from the boom to a secure point on the deck or mast, holding the boom in place and preventing it from moving unexpectedly. This is particularly important when sailing downwind, as the boom is at risk of swinging across the deck if the wind direction changes or if the boat’s course alters suddenly. An accidental jibe can cause serious damage to the rigging and pose a danger to the crew on board.

There are different types of preventers, including:

• Boom Preventer: A line that runs from the boom forward to a cleat or block on the deck, then back to a winch where it can be tensioned.

• Gybe Preventer: A more complex system that uses blocks and tackles to manage the boom’s movement more effectively, allowing for controlled jibes without risk.

• Foreguy: A line similar to a preventer but used to control the movement of the spinnaker pole, ensuring it doesn’t swing uncontrollably during maneuvers.

Application Areas

• Sailing Downwind: The preventer is especially useful when sailing with the wind coming from behind (downwind sailing), where the risk of an accidental jibe is highest.

• Heavy Weather: In strong winds or rough seas, a preventer provides additional control over the boom, reducing the strain on the sails and rigging.

• Night Sailing: When visibility is reduced, and it’s harder to monitor sail positions, a preventer offers an extra level of safety.

• Training and Safety: Preventers are also used in training scenarios to teach new sailors about controlling the boom and handling jibing safely.

Notable Examples

• Simple Line Preventer: A basic setup where a rope is attached to the end of the boom and secured to a point on the deck forward of the mast. This is the most straightforward type of preventer.

• Multi-Part Tackle Preventer: Uses a system of blocks and lines to distribute the load, making it easier to adjust and release under tension. This system allows for controlled adjustments without releasing the line entirely.

• Permanent Preventer System: Some vessels are equipped with permanently rigged preventers that can be engaged or disengaged as needed, offering convenience and quick deployment.

Importance in Maritime Operations

Preventers play a crucial role in enhancing the safety of sailing operations by preventing accidental jibes, which can be hazardous and cause significant damage to the vessel. They provide additional control over sail handling, especially in challenging weather conditions, and contribute to the overall safety of the crew by reducing the risk of injuries caused by swinging booms.

Proper rigging and use of preventers are essential skills for sailors, and their deployment is considered a standard safety practice on sailing vessels. They are simple yet highly effective tools that make sailing safer and more manageable, particularly in heavy winds or when sailing with the wind directly astern.

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