Development Of Underwater Construction Tools And Equipment For U.S. Navy Divers
Authors: Black S.A. , Thomson H.G. , Farber B.W. , Inouye A.T. 
Published: October 2008

New tools and equipment are being developed to improve the effectiveness and capabilities of U. S. Navy Underwater Construction Team divers. Included are a discussion of development requirements, equipment description, and results of operational and field testing. Equipment discussed includes (1) a Lightweight Oil Hydraulic Power Supply, (2) Diver Electrical Safety Equipment, (3) Two-Part Epoxy Grout Dispenser, (4) Emergency Diver Recall, (5) Cable Tracking System, (6) Diver Lift System, and (7) a Seawater Hydraulic-Powered Multi-Function Tool System.

INTRODUCTION

Under the sponsorship of the Naval Facilities Engineering Command and the Naval Sea Systems Command, the Naval Civil Engineering Laboratory (NCEL), Port Hueneme, Calif., is developing tools and work techniques for use by Navy Construction Force (NCF) divers engaged in underwater construction, inspection, maintenance, and repair of ocean facilities. The overall objective of this Underwater Construction Systems (UCS) Program is to increase the readiness and capabilities of NCF divers by providing them with up-to-date, efficient, and effective tools and techniques.

NCF Seabee divers are organized into two Underwater Construction Teams (UCTs), located on the east and west coasts of the U.S. The tasks and the operational sites of the UCTs vary greatly, as do the support equipment and tools needed to conduct their underwater work. Examples of UCT tasks include the survey, maintenance, installation, and repair of cables, pi pelines, and cathodic protection systems, and the repair of piers, quaywalls, and drydocks.

Specific design requirements for UCT equipment include: operation to 190-foot water depths, water temperatures from 28 to 9O °F, suitable for use by SCUBA and surface-supported divers, safe and reliable operation, and maintainable by UCT divers at remote sites. All of the Underwater, Construction System equipment has been laboratory and field tested to insure adequate service life and operational characteristics and suitability for the user. As a final test, the equipment is given to the UCT divers for an independent field operational evaluation. Maintenance manuals, spare parts lists, maintenance schedules, and training recommendations are provided with each item.

This paper discusses the development of several UCS systems, including:Electrical Safety EquipmentLightweight Oil Hydraulic Power SupplyDiver-Operated Grout DispenserEmergency Diver RecallCable Tracking SystemDiver Lift SystemMulti-Function Seawater Hydraulic Tool System

ELECTRICAL SAFETY EQUIPMENT

Divers can be exposed to electrical shock hazards either by direct physica1 contact with an energized circuit or by swimming into a strong electrical field. Immersion in seawater causes a substantia1 reduction of the dry skin contact resistance from a normal 3,500 ohms to 250 ohms or less, so that the voltage required to produce a fatal current flow is significantly less than for a person on land. The U.S. Navy Bureau of Medicine (BUMED) established criteria for diver electrical protection based on the safety code prepared by Electrical Research Association Technology Ltd. (ERA) for the United Kingdom Department of Energy and Ministry of Defense (Royal Navy). The ERA established the following safe exposure equation for 50/60 cycle electrical systems (Ref 1).