Clothing buoyancy and underwater horizontal swim distance after exiting a submersed vehicle simulator

Winter road workers, who drive heavy vehicles over ice-covered waterways, are at risk for ice failure, vehicle submersion, and subsequent drowning in frigid water. Although some jurisdictions require these workers to wear flotation clothing, there are concerns that, following an underwater exit in fast-moving water, increased clothing buoyancy may reduce ability to swim against the current to safely return to the ice opening.

Using a simulator in a swimming pool (3.7 m deep, 28 degrees C), 11 volunteers (5 women) were submersed 8 times each to test the effects from both an Upright and an Inverted position of a normal nonflotation winter jacket (Control), a flotation Jacket, a flotation Overall, and a personal inflatable vest which was inflated (Inflated Vest) on underwater horizontal swim distance. Subjects also rated exit difficulty and impedance, psychological stress, and thermal comfort.

Compared to Control, Jacket, and Overall, the Inflated Vest generally increased exit difficulty, escape impedance, and psychological stress, while greatly decreasing the ability to swim horizontally underwater before reaching the surface (Control, 6.1 m; Jacket, 5.0 m; Overall, 3.4 m; and Inflated Vest only 1.4 m). Swim distance with the Overall was also significantly shorter than Control, but not Jacket.

Flotation clothing (either Jackets or Overalls) is recommended for vehicle travel on ice because they do not impede underwater exit from a vehicle and allow significant horizontal underwater swim distance. An inflatable vest is not recommended because inappropriate premature inflation could increase exit impedance and decreased underwater swim distance.