Inflatable lifejacket requirements for encumbered military personnel

Military personnel’s equipment has become heavier in recent years in order to provide improved combat protection. These encumbered personnel are required to wear a lifejacket for operations over water. Yet, only limited published research has been identified that addresses the adequacy and efficiency of lifejackets to protect heavily encumbered military personnel from drowning. The Evacuation and Lifesaving cell of the Royal Australian Navy (RAN) Navy Engineering Division in collaboration with UNSW and AMC has now concluded its study of the in-water requirements for an inflatable lifejacket that can support encumbered military personnel. A comparison study has been conducted on yoke and bib lifejackets to investigate the expected mouth freeboard tolerances of good and poor fitting lifejackets. The study also considered the shape of the bladder around the head and the effect that face-plane angle has on mouth freeboard. These both impact on head tilt angle. Positive head tilt was expected to improve the survival prospects in water. Static pool experiments with the two buoyancy systems have indicated how much load can be supported. This work was reinforced with wave tank experiments to determine the water ingress into a manikin’s mouth under various load and sea conditions, resulting in recommendations for suitable mouth freeboard clearances. An investigation of the three most relevant standards for this study suggested that the ISO standard best addresses the aspects of encumbered military personnel from drowning. However, it is recommended the technical requirements that can support encumbered military personnel should be additional criteria to this standard