Activation Mechanism: The yellow bobbin is a small, cylindrical device made of plastic or similar material. It contains a water-sensitive mechanism that responds to immersion in water.
Water-Sensitive Material: Inside the yellow bobbin, there is a material that absorbs water. When this material comes into contact with water, it expands and triggers a mechanical action.
Inflation Trigger: The mechanical action initiated by the expanding water-sensitive material is designed to puncture or release a mechanism that holds the CO2 cartridge in place.
CO2 Cartridge Release: Once the triggering mechanism is activated, the CO2 cartridge is punctured or released. This causes the compressed gas (carbon dioxide) from the cartridge to flow into the inflatable chambers of the life jacket or PFD.
Rapid Inflation: As the gas is released into the inflatable chambers, they rapidly fill with air, inflating the device and providing buoyancy to the wearer.