Development of An Underwater Mateable High-Power Cable Connector
Authors: McCartney Joseph F. , Wilson Jeffrey V. 
Published: October 2008

ABSTRACT
Under the sponsorship of the Naval Facilities Engineering Command as a portion of the Deep Ocean Technology Project, the Civil Engineering Laboratory (formerly NCEL) has developed prototype high-power electromechanical connectors for use with deep ocean cable systems and structures. There are two basic connector configurations: one for mating underwater (wet) and one for mating in air (dry). Both are designed for 360 kw, 60 Hz, 4,160/2,400 VAC power at depths to 6,000 ft, with a mechanical breaking strength of 50,000 lb. The wet connector is capable of repeated underwater mating by divers, remotely operated actuators, or submersibles with manipulators. Increased performance in depth, strength, or power would require a simple extension of the design, although any significant increase in transmission voltage levels would require further development. These connectors were evaluated in a series of pressure vessel and open sea tests to depths of 6,000 ft. The final configuration performed with no electrical or mechanical degradation after 33 mating at depth Sustained immersion and power tests for 1 year at 600 ft and in the tidal zone confirmed the endurance of the designs.
This development is the first demonstration of a capability for underwater mating of major electrical/mechanical components of seafloor structures. The resultant technology provides significant new options for the design of advanced underwater structures, primarily through increased flexibility in installation procedures and a major increase in maintenance and repair capabilities.

INTRODUCTION
This program, sponsored by the Naval Facilities Engineering Command, supports the Navy's requirement for the development and operation of seafloor installations under the Deep Ocean Technology Project. Electrical energy for these installations, at power levels from a few kilowatts to several hundred kilowatts, can best be provided from shore-based or surface-tendered sources. 1 Typical undersea installations utilizing such power supplies are illustrated in Figs. 1 and 2. They include such components as bottom-laid cables, buoy systems, fixed seafloor structures, underwater work vehicles, diving stations, and tensioned arrays for scientific observations. As the complexity of these structures increases, the techniques of modular construction become more important and the ability to isolate or replace sections without recovering an entire structure becomes essential. The flexibility afforded by appropriately located connections for both installation and maintenance is a prime factor in obtaining efficient operation, optimum construction methods, and long life with minimum down time.
A serious limitation in undersea operations prior to the development reported here was that undersea cable connectors were not available for this range of power and strengths applications. This lack of suitable connectors severely complicated structure and equipment installation and made maintenance both costly and difficult.
The development described in this report concentrated on high-power, high-strength connectors. The specific goal was the development of a high-power electromechanical connector system capable of being mated either underwater (wet) or in air (dry).