The concept of an occupant submarining under a lap belt has been known by vehicle manufacturers since the 1960’s. Submarining occurs when an occupant’s pelvis rotates down and forward and allows the lap belt to slide over the pelvic bones into the soft abdominal tissue.
Injuries that occur when an occupant submarines under a lap belt:
1. Horrific intra-abdominal injuries
2. lumbar spinal fractures
3. lower leg fractures
Several design flaws can lead to submarining:
1. Rigid buckle stalk raises belt above pelvis
2. Buckle stalk is too tall and raises belt above pelvis
3. Ineffective seat ramp or cushion design
4. Belt anchorage location too far aft or forward
5. Belt anchorage angle too steep or shallow
6. Too much slack in the belt
Each of these design flaws has one component in common—they affect belt fit or belt geometry. Alternative designs that will prevent or minimize the risk of submarining range from using a shorter, more flexible buckle stalk to incorporating an antisubmarining seat. More elaborate design fixes include pyrotechnic pre-tensioners, vehicles with ABTS and vehicles with seat mounted lap belt buckles. These help reduce belt slack and help secure the occupant closer to his pre-accident seated position.
Submarining also occurs if the seat bottom cushion slides forward due to improper attachment. When a seat slides forward, the antisubmarining seat ramp is rendered useless. Submarining has been observed in lap belt only, 3-point continuous loop, and 2-point motorized/automatic shoulder belt configurations. FMVSS 209 previously mandated that a lap belt should remain below the pelvis under all accident conditions, however this provision was dropped in 2002.
Submarining can cause serious injuries to the occupants of the vehicle in an event of accident. It has a likely probability of occupants being ejected from the vehicle. If the occupants are ejected from the vehicle, then, the case becomes crash worthiness and you need to consult us to get the advice from the nation’s top crashworthiness lawyer who has been handling crashworthiness cases for more than two decades now.
Call us at 214-324-9000 for more information on your individual crashworthiness case.