Chapter XI

ENGINEERING IN THE MARINE ENVIRONMENT

Ocean Engineering

A strengthened engineering component of marine sciences and technology is one of the objectives set forth in legislation. Engineering, however, is not an end but rather a means for tools, techniques, facilities, and services must match requirements for research and for applications. By a number of circumstances, some the result of planned marine development, but the most fortuitous contributions from other fields, we find the technologies ripe for meeting new marine requirements.

Ships and submarines, undersea cables and tunnels, coastal protection, and offshore oil operations are examples of successful ocean engineering. These evolve from classical engineering principles, modified to take into account the different environmental factors and forces of the oceans, and oriented to the tasks man wants to accomplish in the sea. Such engineering thus concerns propulsion, materials, sources of energy, structures, communications, etc. Engineering design must accommodate such factors as cost, safety, reliability, availability of components, and ease of maintenance. Implicit, too, is the systems approach to problem solving, taking into account such environmental factors as:

-sea surface motion;

-tides and currents;

-wave impact and wind loading;

-heavy hydrostatic pressures;

-large buoyant forces;

-opacity of sea water to electromagnetic energy;

-high attenuation and scattering of light energy;

-high conductivity of sounds;

-lack of gaseous oxygen for man or chemical combustion;

-presence of all common elements in sea water;

-variable two-phase nature of water-bottom interface; -severe corrosion and fouling.

Since the first ship was built, marine engineering and naval architecture have been vital elements of national security. A fleet, second to none for more than thirty years, reflects the high technical skills of the U.S. Naval Establishment, and the significant contributions of the technical industries that support it. By far the largest fraction of Federal funds for ocean engineering has been spent in the defense area and, for some years to come, this is almost sure to continue. Today, however, new demands are being added. For nonmilitary as well as military reasons, man is venturing below the thin layer near the ocean surface to utilize the relatively unexplored and unused third dimension of the sea.

Search and Recovery-An Area of Emphasis

As noted earlier, an area considered by the Council as deserving special emphasis concerns a deep-ocean search and retrieval capability. Steps to increase development in that field are proposed for the Navy for fiscal year 1968 in the context of that agency's mission. The Thresher catastrophe dramatized both the compelling reasons for finding and recovering objects from the deep-ocean bottom, and the frustrating discovery that, in 1963, this Nation had virtually no capability to accomplish such tasks in water more than 400 feet deep. In January 1966, when two U.S. aircraft collided over Spain, the importance of deep-ocean search and recovery skills was again confirmed. The subsequent recovery of an unarmed nuclear weapon from 2,850 feet of water near Palomares, demonstrated that the Nation had acquired some capability, embryonic though it might be, in the three intervening years. The task, however, required three months, dozens of ships and aircraft, thousands of people, and millions of dollars. Subsequently, the Navy has conducted a dozen or more search and recovery operations which not only salvaged especially valuable aircraft, torpedoes, and other equipment, but also developed needed experience.

To date, the deepest important recovery was from 3,000 feet, yet more than eighty percent of the world seas exceed that depth. To improve and extend that capability, the Navy program for fiscal year 1968 contains funds to start the development of a small, manned submersible and associated equipment capable of operating eventually at depths down to 20,000 feet. Only deep trenches which comprise two percent of the world's oceans are deeper. Initial emphasis will be on development of suitable materials and equipment, and on outfitting the currently approved 3,500-foot depth rescue vehicles with equipment to gain more practical experience in search and recovery at sea.

A new system for rescuing personnel from sunken combatant submarines is currently under development to replace the McCann bell system developed over thirty-five years ago. The central element of this new rescue system is a 30-ton, 50-foot rescue vehicle capable of removing two dozen people per trip from a disabled submarine. Figure 18 shows how people will transfer from the disabled submarine to the rescue vehicle. The first prototype rescue submarine is scheduled for delivery in June 1968 and construction of a second submarine begins the next year. The vehicle can be transported in the C-141 aircraft, thus enabling the rescue system to respond quickly to a submarine disaster almost anywhere.

Salvage

The Navy program includes development of techniques to raise sunken ships or large elements from deep water. Studies being conducted now emphasize recovery from continental margin depths1,000 feet or less. For salvage in deeper water, economical solutions are being sought for techniques for generating large but controllable lift and buoyancy forces; means of eliminating or minimizing the adverse effects of sea-surface motion; extension of man-in-the-sea to

from disabled submarine.

75-954 O-67-7

ment, power sources, and underwater workboats to augment man's capabilities at deeper depths.

Ships and Deep Submersibles

As one of the nine areas for emphasis, the Council endorsed a proposal of the Coast Guard that one of that agency's major ships, planned originally as a replacement for the twenty-three-year-old Evergreen on the North Atlantic ice patrol, be designed and outfitted especially for subpolar oceanography. In addition to ice patrol, it will be employed to investigate water-mass interchanges in support of the Navy and will be one of the most effective tools to accentuate a program of oceanography in near-Arctic waters.

This is the only new ship for marine sciences being requested for general observational activities in the fiscal year 1968 program. To some extent, the slowing down of ship construction reflects the foresight of decisions over the past few years in funding new ships in phase with anticipated requirements. It also signals an interval of taking stock and considering what platforms or devices other than ships may better serve needs for marine observations. Aircraft, helicopters, ground effect machines, and stationary buoys, either manned or unmanned, offer alternatives to be examined.

The deep-submergence research vehicle is one of the most exotic new developments in the arsenal of research tools. The Government's acquisition of the bathyscaphe Trieste in 1957 signaled the beginning of this era, and the privately funded design and construction of Aluminaut in 1958 constituted a quantum jump in depth capability of a true submarine. A whole family of such vehicles has followed, with a wide span of depth, performance, and payload characteristics. Most have been designed and built by private industry, but more often than not are deployed on Federal research and development projects. The evolution of these vehicles, shown in Figure 19, was accompanied by an initial lag of demand behind supply. 1967 may be the year of transition. Two Alvin-type vehicles should be delivered to the Navy in fiscal year 1968, and unless more small submersibles are built in the near future, the demand for these craft may exceed the supply.

Of particular importance is the NR-1, the small, nuclear-powered, ocean engineering and research submersible being constructed by the Navy which should be ready for operation next year. Its endurance of thirty days submerged (as compared with a maximum of about thirty hours for a working dive in today's vehicles) opens significant opportunities for exploration of the Continental Shelf and for biological, physical, and acoustic research.

Experience in operation—including the unprecedented mobilization of these capabilities for the ordnance search off Spain-has pro