Lifebuoys, Lights and Man-Overboard Equipment

Technical guide to SOLAS lifebuoys under the LSA Code: 2.5 kg vs 4.0 kg rings, 30m bridge drop-test standards, self-igniting lights, and bridge-wing MOB smoke marker systems.

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The circular lifebuoy is the most recognized maritime survival appliance in human history. Positioned along open weather decks, bridge wings, and ship gangways, lifebuoys provide an immediate flotation lifeline when a crew member or passenger falls overboard. In the confusion of a sudden man-overboard (MOB) incident, throwing a lifebuoy marks the casualty's position, provides immediate positive buoyancy, and assists rescue vessels in visual tracking. Under **SOLAS Chapter III** and the **IMO LSA Code**, lifebuoys are precision-engineered safety appliances subject to strict weight, buoyancy, drop-height, and accessory mandates. Shipowners and marine superintendents must ensure that all onboard lifebuoys meet statutory requirements and remain ready for instant deployment. ## Engineering Standards for SOLAS Lifebuoys 1. **Physical Dimensions and Mass:** - Outer diameter: Maximum 800 mm; Inner diameter: Minimum 400 mm. - **2.5 kg Lifebuoy:** Standard ring fitted with buoyant lifelines or automatic self-igniting lights. - **4.0 kg Lifebuoy:** Heavy-duty ring mounted on bridge wings, designed with sufficient mass to trigger the release mechanism of quick-release Man-Overboard (MOB) light and smoke markers. 2. **Material and Buoyancy:** - Manufactured from inherently buoyant polyurethane or closed-cell foam encased in high-density polyethylene (HDPE). - Must support at least **14.5 kg of iron in fresh water for 24 hours** without losing buoyancy. 3. **Drop-Test Dur...