Designing a Serious Main Boom Preventer
Controlling the most dangerous part of the boat
Overall, sailing is a safe endeavor, but it is essential to maintain situational awareness. Controlling the main boom is crucial. Uncontrolled, the mainsail boom and sheet are perhaps the most dangerous part of the rig, and have caused numerous serious injuries and fatalities.
When sailing off the wind – any point of sail greater than roughly 100 degrees off – you are a wind shift, inattentive skipper, or autopilot failure away from an accidental gybe. By this, I mean the wind coming onto the leeward side of the main and causing the boom to slam across the boat.
A cascade of problems can occur during an accidental gybe. The most obvious risk is the boom striking a crew member. A full-on boom strike on any part of the body will cause potentially serious injury, and head and neck strikes are likely to be deadly. The boom will come across the boat with great speed and will take up on the sheet on the other side. This shock load is enough to break the sheet, blocks, or traveler. If you lose any part of the mainsheet, the boom is now an out-of-control battering ram. With the sheet gone, the only thing stopping the boom is the standing rigging on the mast. Under harsh enough conditions, the main boom can take down the rig.