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The Seafloor Borehole Array Seismic System (SEABASS) has been developed to measure the pressure and three dimensional particle velocity of the VLF sound field (2-50HZ) below the seafloor in the deep ocean (water depths of up to 6km). The system consists off our three-component borehole seismometers (with an optional hydrophone), a borehole digitizing unit, and a seafloor control and recording package. The system can be deployed using a wire line re-entry capability from a conventional research vessel in Deep Sea Drilling Project (DSDP) and Ocean Drilling Project (ODP) boreholes. Data from below the seafloor are acquired either on-board the research vessel via coaxial tether or remotely on the seafloor in a self-contained package. If necessary the data module from the seafloor package can be released independently and recovered on the surface. This paper describes the engineering specifications of SEABASS, the tests that were carried out, and preliminary results from an actual deep sea deployment. Ambient noise levels beneath the seafloor acquired on the Low Frequency Acoustic-Seismic Experiment (LFASE) are within 20dB of levels from previous seafloor borehole seismic experiments and from land borehole measurements. The ambient noise observed on LFASE decreases by up to 12dB in the upper 100m of the seafloor in a sedimentary environment., This work was carried out under JHU Contract # 602809-0 and under ONR contracts #N00014-89-C-0018, #N00014-89-J-1012, and #N00014-90-C-0098.

Funding was provided by the Office of Naval Research through contract Number N00014-84-C-0134.

This report desribes a new, easy to install, reliable electromechanical cable termination to mechanically attach and electrically connect cable lowered instrument packages to their lowering cable., Funding was provided by the National Science Foundation through Grant No. OCE 8821977.

This report documents the work performed by the Woods Hole Oceanographic Institution (WHOI) and the Battelle Memorial Institute from August 1988 to December 1992 in the NSF sponsored development of an Integrated Seawater Sampler and Data Acquisition Prototype. After a 6-month initial design study, a prototype underwater profiing unit was designed and constructed, containing the water acquisition subsystem, CTD and altimeter, control circuitry and batteries. A standard WHOI CTD was adapted for use in the underwater unit and was interfaced to the underwater controller which had a telemetry module connecting ít with a deck control unit. This enabled CTD data to be logged in normal fashion on shipboard while additional commands and diagnostics were sent over the telemetry link to command the underwater unit's water sampling process and receive diagnostic information on system performance. The water sampling subsystem consisted of 36 trays, each containing a plastic sample bag, the pump and control circuitry. The sample bags, initially sealed in a chemically clean environment, were opened by pumping the water out of the tray, thus forcing water into the bag by ambient pressure. The command system could select any bag, and control the water sampling procss from the surface with diagnostic information on system altitude, depth, orientation and cable tension displayed in real time for operator information. At sea tests confirmed the operation of the electrical and control system. Problems were encountered with the bags and seals which were partially solved by further post cruise efforts. However, the bag closing mechanism requires further development, and numerous small system improvements identified during the cruises need to be implemented to produce an operational water sampler. Finally, initial design tor a water sampler handling and storage unit and water extraction system were developed but not implemented. The detailed discussion of the prototype water sampler design, Funding was provided by the National Science Foundation through Grant No. OCE8821977.

Under the sponsorship of the Naval Surface Warfare Center (NSWC), Dalgren Division, White Oak, Marland, the Ocean Systems & Mooring Laboratory of the Woods Hole Oceanographic Institution devised (1991) and conducted (1992) an experiment to measure the dynamic response of a full scale model of the CAPTOR mine, submerged and moored in strong tidal currents near Woods Hole, MA. Specifically, the purpose of this sophisticated engineering experiment was to obtain long term, high frequency measurements of the spatial position of the CAPTOR body, of the tension at both ends of the mooring line, and of the mooring line strumming, as a function of the currents prevailing at the site. This report first describes the main components and the method of deployment of the complex CAPTOR Dynamics Experiment (CAPTORDYN) set up. It then presents the mechanical and electrical designs of the entire system. Finally a review of the results obtained concludes the report., Funding was provided by the Naval Surface Warfare Center under Contract No. N60921-91-C-0216.

A real-time tomography system has been developed which combines ocean acoustic tomography with satellite-based time keeping and satellite telemetry. The basis of the system is the acoustic tomography transceiver and its associated acoustic navigation grid. To this basic system, a link to the surface has been added to provide a pathway for telemetry of the tomographic data to shore and a downlink for satellite-derived time which is used to correct the transceiver's clock. The surface buoy contains a GPS receiver, clock comparator, system controller and multiple ID Argos transmitters. Processed tomography signals, transceiver location data time, time drift and surface buoy engineering data are transmitted to satellite using a total of 32 data buffers transmitted every eight minutes. The report describes the real-time tomography system in detail, with particular emphasis on the modifications implemented to convert the standard tomography instrument to a real-time oceanographic tool., Funding was provided by the Office of Naval Technology under Contract No. N000-14-C-90-0098.

As part of a development effort in the field of moored arrays sponsored by the Office of Naval Technology, the Ocean Structures and Moorings Laboratory (OSM&L), Applied Ocean Physics and Engineering Department (AOP&E), Woods Hole Oceanographic Institution (WHOI) conducted a study in 1991 to assess the feasibility and the merits of several self-deployable mooring designs. This study included a brief review of the state of the art, the performance of lab tests to evaluate different mooring line payout concepts, and the preliminary design of a typical candidate mooring. The results of this study are presented in this report. The report first reviews three types of single point moored arrays which are amenable to self-deployment: subsurface, subsurface with surface expression, and surface with bottom inverted catenary. It then describes the features common to all self-deploying moorings: techniques for line and instrument storage, means for controlled payout, bottom finders and lock up mechanisms, and it also outlines desirable specifications for sensor sizes, cables and connectors. Next the report reviews typical deployment scenarios from the bottom up or from the surface down as they apply to the three types of moorings retained. In its final section, the report presents the conceptual design of a 6000 meters depth capability, bottom up deployment, candidate mooring. This configuration should be of strong interest when contemplating the deployment of a large number of identical subsurface moorings, interconnected by a bottom cable, and in "close" proximity to one another. The case study outlines the design objectives and the current profiles, specifies the main components, evaluates their performance with the help of a standard computer program, and presents packaging and payout control details. Finally, a plan is proposed for the controlled, in-situ evaluation of a prototype., Funding was provided by the Office of Naval Technology under Contract No. N00014-90-C-0098.

The Seafloor Borehole Array Seismic System (SEABASS) has been developed to measure the pressure and three dimensional particle velocity of the VLF sound field (2-50HZ) below the seafloor in the deep ocean (water depths of up to 6km). The system consists off our three-component borehole seismometers (with an optional hydrophone), a borehole digitizing unit, and a seafloor control and recording package. The system can be deployed using a wire line re-entry capability from a conventional research vessel in Deep Sea Drilling Project (DSDP) and Ocean Drilling Project (ODP) boreholes. Data from below the seafloor are acquired either on-board the research vessel via coaxial tether or remotely on the seafloor in a self-contained package. If necessary the data module from the seafloor package can be released independently and recovered on the surface. This paper describes the engineering specifications of SEABASS, the tests that were carried out, and preliminary results from an actual deep sea deployment. Ambient noise levels beneath the seafloor acquired on the Low Frequency Acoustic-Seismic Experiment (LFASE) are within 20dB of levels from previous seafloor borehole seismic experiments and from land borehole measurements. The ambient noise observed on LFASE decreases by up to 12dB in the upper 100m of the seafloor in a sedimentary environment.

As part of a development effort in the field of moored arrays sponsored by the Office of Naval Technology, the Ocean Structures and Moorings Laboratory (OSM and L), Applied Ocean Physics and Engineering Department (AOP and E), Woods Hole Oceanographic Institution (WHOI) conducted a study in 1991 to assess the feasibility and the merits of several self deployable mooring designs. This study included a brief review of the state of the art, the performance of lab tests to evaluate different mooring line payout concepts, and the preliminary design of a typical candidate mooring. The results of this study are presented in this report. The report first reviews three types of single point moored arrays which are amenable to self-deployment: subsurface, subsurface with surface expression, and surface with bottom inverted catenary. It then describes the features common to all self-deploying moorings: techniques for line and instrument storage, means for controlled payout, bottom finders and lock up mechanisms, and it also outlines desirable specifications for sensor sizes, cables and connectors. Next the report reviews typical deployment scenarios from the bottom up or from the surface down as they apply to the three types of moorings retained. In its final section, the report presents the conceptual design of a 6000 meters depth capability, bottom up deployment, candidate mooring. This configuration should be of strong interest when contemplating the deployment of a large number of identical subsurface moorings, interconnected by a bottom cable, and in 'close' proximity to one another.