Underwater Ship Husbandry

ABSTRACT The current Naval capabilities in underwater ship maintenance, repair and inspection are reviewed in conjunction with the tools and techniques available to divers in this field. By upgrading ship husbandry capabilities the Navy anticipates lengthening drydocking intervals and improving combatant readiness. Hardware contributions originating at the Naval Coastal Systems Laboratory are presented. Selected findings of the NAVSEA sponsored 1975 Underwater Ship Husbandry Workshop are discussed. INTRODUCTION As recently as 1972 there were nine Naval Shipyards spread along the two coasts of the continental United States and one more in Hawaii. These facilities provided the majority of drydocks available to the Navy for repainting and overhauling ships on a nominal three year cycle. Two of these yards have been closed but the fleet has not decreased proportionately in size: the ship husbandry diver is asked to make up much of the difference. In January; 1975, the Navy's first Underwater Ship Husbandry Workshop was held at the Naval Coastal Systems Laboratory (NCSL) in Panama City, Florida, under the sponsorship of the Supervisor of Diving (SUPDIVE), Naval Sea Systems Command (NAVSEA). Attended by nintyseven divers, researchers and administrators, this workshop provided a coherent picture of present and future work at several important levels, and along with the specific tasks being performed for SUPDIVE by NCSL, forms the basis of this paper. The responsibility of ship husbandry divers can usefully be broken down into three categories: repair, maintenance, and inspection. U/W repair and maintenance are the means through which Naval ships are becoming progressively less dependent on the expensive and time consuming drydocking routine. Additionally it is currently believed that hull cleaning, a maintenance operation, will make possible very substantial fuel savings. Reduced drydocking expenses and fuel economy are providing motivation for the full utilization of underwater ship husbandry techniques. Repair jobs are varied in nature, and on the surface it seems that almost every underwater feature eventually needs to be fixed. But in reality the business of blanking hull openings and sea chests accounts for about one third of all repair jobs. For the most part the repair work is carried out from inside the ship once the blanking is complete. The second most popular jobs involve repairs on sonar domes and transducers. Other repair functions common in ship husbandry work involve shaft seals, work inside ballast tanks, screw changes, clearing fouled lines and making temporary patches. Although most of these latter jobs occur infrequently, they address problems that would be serious enough to warrant dry-docking if diver services were not available. One loose distinction between repair and maintenance jobs is, in fact, whether or not the ship can continue to operate if nothing is done for the problem at hand. Maintenance work has traditionally been limited to such jobs as zinc replacement, cleaning strainers and pitswords and grooming propellers. However, a large percentage shift in the time allocation between repair and maintenance jobs is anticipated if hull cleaning becomes a widely adopted procedure.