OCEANS '78

In November 1967, the National Data Buoy Development Project was established by the United States Coast Guard. The primary purpose of this organization was to verify and standardize the design and performance of environmental data buoys by establishing an extensive network of sophisticated buoys capable of delivering a wide variety of data, supplemented by smaller buoys of simpler design for speci... View full abstract»

A new buoy system has been developed for the U. S. Bureau of Land Management to gather, process, and telemeter oceanographic data from the Georges Bank area of the New England outer continental shelf. The buoy system incorporates a taut-moored subsurface sphere 6 m below mean water connected to an anchor by an instrument string using an oil-filled synthetic rubber hose as the strength member. Thre... View full abstract»

The development of a successful meteorological drifting buoy has been undertaken. Buoys which measure sea surface temperature and barometric pressure have been built, tested and successfully deployed. A description of this buoy is given, with details of the sub-systems. View full abstract»

In 1975, the NOAA Data Buoy Office (NDBO) began deploying a data acquisition system identified as the Prototype Environmental Buoy (PEB) payload on their operational buoys. This payload could report environmental data from remote ocean areas to shore through radio telemetry, but could only receive data inputs in the form of analog voltages. Digital data could not be accommodated. NDBO subsequently... View full abstract»

A NEW INSTRUMENT FOR MEASURING AND REPORTING OCEAN WIND WAVES HAS BEEN CONSTRUCTED, TESTED AT SEA, AND PUT TO USE IN FIELD STUDIES OF THE TRANSFER FUNCTION OF OPERATIONAL WAVE MEASURING SYSTEMS ON LARGE DATA BUOYS. THE PROTOTYPE WRANSAC WAS INTEGRATED FROM AN EXISTING MICRO-COMPUTER, A SATELLITE RADIO TRANSMITTER, AND A WAVERIDER. TWENTY MINUTES OF WAVE DATA ARE PROCESSED AND PRODUCE HOURLY REPORT... View full abstract»

This paper describes a system for measuring the direction of ocean wave propagation, as well as wave height and period. The system employs a conventional wave follower buoy, modified so as to provide compass, pitch and roll signals in addition to the vertical component of buoy acceleration. The modifications are indicated in the paper, and the buoy was tested in two sea state conditions in Narraga... View full abstract»

The Digital Survey Fathometer®(DSF- 600) is a portable, dual frequency recording depth sounder with a permanent chart display, digital output, and features automatic phase changing of the chart display. Operating at frequencies of 40kHz and 200kHz (frequency switch selected), the DSF-600 provides high resolution, quality bathymetric profiles in water depths to 310 fathoms. By inter... View full abstract»

The expanding and increasing affluent world population has brought about a growing need for commodities and energy on a global scale. Two major marine activities affected by this are shipping and mining. The shipping industry, because of its up to 30 meter draft superships, and the mining industry (particularly the hydrocarbon sector), both require timely and accurate bathymetric charts for safe a... View full abstract»

A portable acoustic tracking system has been developed for the Navy to track underwater construction teams in water depths to 300 ft. The tracking system can be deployed and operated by the divers and is intended for use in remote areas and for nearshore survey, maintenance, and construction work. A self-calibrating system provides a geographically justified track for up to eight divers. Diver pos... View full abstract»

This paper describes a novel idea of reducing multipath interference in underwater acoustic communication systems. The proposed idea is based on the observation that the time separation between direct and multipath waveforms can be utilized to suppress the multipath interference. A proposed system employs a carrier with instanteous frequency swept periodically in time over a broad frequency range.... View full abstract»

A design is presented for a system providing highly reliable command and control acoustic communications between a mother ship and a number of small, fast submersibles. The small submersibles may be employed for underwater mining, exploration, bottom mapping, or military surveillance. Modulation and coding design is presented; the techniques discussed provide multiple protection against multipath ... View full abstract»

In the demodulation of underwater acoustic signals, timing determination is usually based on the leading edge of a pulse, and is therefore subject to errors that are functions of pulse rise time and signal level. This paper describes a system using a phase-locked loop demodulator to determine the time of arrival of a frequency-shifted pulse. In this system, timing is shown to be essentially indepe... View full abstract»

A considerable amount of overwater dissipation and wind profile data obtained from shipboard measurements were interpreted relative to the representation of the drag coefficient. Drag coefficients were interpreted relative to wind speed, wave and hydrostatic stability influence. It was noted that at all wind speeds and particularly at low wind speeds, drag coefficient values are larger when large ... View full abstract»

The mechanical properties of chitosan membranes have been investigated as a function of several processing variables. Chitosan, the deacetylated derivative of chitin (N-acetyl-D-glucosamine), was processed from blue crab shells from Virginia. Various chitosans, which had been deacetylated under different conditions, were dissolved in weak acetic acid and then cast into clear, flexible membranes ab... View full abstract»

Survival of Macrocystis spp. gametophytes is a function of sediment depth on the surface to which they attach. Relative survival varies as an exponential function of calculated mean depth in all cases. If spores attach to a surface prior to sediment settlement, no survival is noted after four days at depths above 500 microns. If spore inoculation occurs after settlement, no survival is noted for c... View full abstract»

The Naval Research Laboratory's investigation of the protection of wood in marine service which began with an in depth study of creosote, is now concentrating on a study of the active antiborer constituents of naturally bioresistant woods. This work is now focussing on woods which are resistant to limnorians, marine crustacean isopods, because most current protective measures are inadequate agains... View full abstract»

Labyrinthula is a saprophytic colonial marine protist found on Zostera marina. It consists of cells which move only within an elastic matrix thought to be synthesized and secreted by the cells themselves. Although they have no visible means of locomotion, that is, no cilia, flagella or podia, the cells exhibit movements at velocities up to200 mu/min. The extracellular matrix also exhibi... View full abstract»

An underwater communications system is described which utilizes Technology Development Corporation's (TDC) Hydrocom coupled to a Radio Retransmission Buoy. Hydrocom is nonacoustic, utilizing instead an electric current field which is not adversely affected by thermoclines, reverberation, or interferometer effects. It can be operated in noisy and confined environments where acoustic systems are sev... View full abstract»

A technique is proposed as an aid to the marine salvage master at sea and the ocean engineer. The aid may be used to find line size, factors of safety, maximum operating conditions, salvage object parameters and other useful information relating to the lifting or lowering of heavy objects at sea. A computer program based on Arthur D. Little, Inc. equations for maximum dynamic line force is used to... View full abstract»

Underwater breathing apparatus can be effectively evaluated by measuring the external work of breathing. This paper reviews the existing and the proposed standards for demand-air breathing apparatus and recommends improvements to the Bentley-Reimers criterion. An automated method of collecting data on the external work of breathing is also described along with test results of various demand-air br... View full abstract»

An innovative approach to maintenance and repair inside reactor vessels without dewatering has been accomplished by the utilization of underwater technicians. The presence of water provides shielding to the workers thereby reducing both the radiation dosage and the dose rate and permits much longer stay time in the repair area. This provides several distinct benefits: (1) the number of people expo... View full abstract»

Stud welding is a simple process which requires no skill of the operator. Experiments were conducted to determine whether underwater stud welding could be made. Most experiments were made with mild-steel studs 3/4 inch in diameter. Base plates used were mild steel and HY-80 steel, 1/2 and 1 inch (6.4 and 25.4 mm) thick. It was found that stud welding could be made successfully under water. In the ... View full abstract»

The Work Systems Package (WSP), following two years of at-sea testing and evaluation, has completed an extensive laboratory time-motion analysis. This analysis, designed to simulate remote operation, provided a controlled evaluation of the system. Instrumentation was installed to provide time-motion and power consumption data on system components. The work tasks were divided into numerous subtasks... View full abstract»

The present paper compares the demographic developments which have characterized the coastal zone in conterminous United States. The population changes in the coastal counties are analyzed for the two census periods 1950-1960 and 1960-1970, and population estimates made in 1974. The coastal counties are grouped into three classes: coastal urban, non coastal urban, which are part of coastal SMSAs a... View full abstract»