Weight Considerations for Deep Submersibles

Abstract

Conventional shallow submersible vehicles depend on the pressure hull for buoyancy, but deep submersibles depend on some type of bulk material for buoyancy. As a consequence, the design of very deep submersibles requires new considerations on the vehicle weight. The purpose of this paper is to evaluate the many parameters which affect the boat weight to see which ones are most influential on total weight. To accomplish this objective, a simplified mathematical expression is derived which describes the total weight for a deep submergence vehicle. The expression contains both structural and nonstructural weight items. The structural items include the pressure capsule, outer hull, foundations, and hard tanks. The nonstructural items are the equipment, buoyancy material, and payload. Each weight item is then examined in detail to determine what parameters affect the boat weight. The results show that the greatest weight reduction is possible with the equipment. This is because the state-of-the-art equipment used for deep submersibles has a weight almost equal to three times its displacement, and to furnish sufficient buoyancy material in the boat to float such equipment results in a large weight penalty.