6,000 Foot Submersible

Abstract

Abstract This paper demonstrates the engineering feasibility of a submersible with a working depth of 6,000 feet that could be operated manned or potentially operated as an unmanned vehicle. The key to the concept is the pressure hull consisting of geometrically arranged intersecting spheres. The concept is unique in the use of a central sphere with intersecting spheres arranged in a hexagonal configuration around the central sphere with additional intersecting port and starboard aft spheres facilitating twin screw propulsion. The structural advantages of spherical pressure hulls are presented and discussed. It is also explained how the use of intersecting spheres for the pressure hull allows a non-cylindrical design and greatly improved arrangement possibilities. The principles used to design the required reinforcing rings at the sphere intersections and the sizing of the columns where the reinforcing rings intersect are presented. A notional design with 6,000 foot capability is presented to show the feasibility. The notional design presented has the internal volume, power, and endurance to complete complex underwater work. It is also proposed that the notional design could be operated remotely or autonomously as desired to validate capabilities and safety or as necessary in high risk environments. Introduction Engineering being the art of the possible, the intent of this paper is to present a possible submersible vehicle capable of doing significant work at a depth of 6,000 feet in the open ocean. There are currently a variety of submersible vehicles available and operating worldwide. Many are unmanned and are operated remotely from a surface vessel. This category of underwater vehicle is generally identified by the acronym ROV (remotely operated vehicle). All of the ROV's are both enabled and limited by the need for an umbilical from the surface. In most cases this umbilical provides a connection for control, data transfer, and power. With power being provided through the umbilical the underwater mission time can be essentially unlimited, but the bulk and drag can be a significant restriction. ROVs are being developed that use only their onboard power source and use the umbilical only for data transmission and control. This greatly reduces umbilical drag and allows greater mobility, but mission time is limited by onboard power storage. Another variation of this concept is to eliminate the umbilical entirely and the vehicle operates autonomously (AUV) in accordance with a set program or based some sort of " smart?? control. The AUVs have the advantage of no umbilical drag or operating radius limitations, but they don't have the real time high speed data transfer capability provided by an umbilical. These vehicles vary greatly in size with greater work capability being possible as the vehicles get larger in size. Another category of submersible vehicle is those that are designed to carry human operators to the work site underwater. There are a limited number of vehicles in this category that can operate in the 5,000 to 6,000 foot depth. Further the majority of vessels in this category are designed and operated for scientific observation and research, not undersea work. It is in this context that the current concept is offered. It is intended to show the feasibility of a submersible vehicle that can perform significant work at depths up to 6,000 feet operating as a manned vehicle, an autonomous vehicle, or a remotely operated vehicle requiring only a data/control umbilical. As with most submersible vehicles capable of carrying human operators to this depth, the current concept will utilize the inherent structural advantages of spheres. The unique feature of the current concept is the use of those spheres joined in a non-linear geometric pattern, and it is this unique structure that makes this concept special.