THE EFFECT OF NON‐CONTACT EXPLOSIONS ON WARSHIP MACHINERY DESIGN.

Abstract

Summary.The widespread damage to machinery caused by non‐contact under‐water explosions caused much concern early in the war, and several trials have been carried out to investigate this problem. Photographs of typical damage on service have been included to show the serious nature of the problem.The phenomena caused by an under‐water explosion are briefly described, and the effect of the pressure pulse caused by it traced to the ship and thence to specific machinery items. While it is not possible to formulate a definite theory to cover the motion caused by the explosion, it is found that a close approximation can be made to the velocity of an item in a ship from energy principles, a simplified theoretical basis for this being given in Appendix I.The magnitude of the accelerations are then discussed and the effect of such suddenly applied motion on machinery design is considered.Since one of the first requirements was to modify existing machinery to withstand these shock forces as far as possible details of typical modifications are given in Appendix II.As shock is not the only criterion of design, many machines cannot be designed to withstand such forces, and special mountings to reduce the forces are discussed.