1. Three types of instrumentation were used: during the tidal data, in 

 situ current velocity, and current velocity profile phases of the experiment. 

 This appendix provides a brief description of the instruments, followed by 

 detailed specifications provided by the manufacturer. 



2. Tidal data were collected using Sea Data, Inc., Model 635-11 Wave 

 and Tide Recorders. The 635-11 is a self-contained digital-recording instru- 

 ment, capable of accurately measuring and recording water pressure. Accuracy 

 of the instrument is attained by use of the Paroscientific , Inc., quartz crys- 

 tal oscillating pressure transducer, which exhibits a 0.005 -percent maximum 

 worst-case hysteresis error, over a full range pressure excursion. The 

 instrument electronics employs all C-MOS circuitry to minimize power drain. 



An ultra-accurate quartz clock allows precise measurement of the sensor's 

 frequency. Data are recorded on a highly precise digital tape recorder, which 

 writes on four tracks at an 800 bits -per- inch density, allowing 15 -megabit 

 data capacity on a 450 -min cassette tape. 



3. The Datasonics, Inc., "AQUARANGE: Acoustic Command System is a 

 multipurpose ranging, position, and relocation system. Applications of the 

 system include long baseline acoustic navigation, ranging and subsea 

 instrumentation. It may be deployed as a recoverable position marker or data 

 telemetry transponder or as a pop-up buoy marker. Operating in the 30-kHz 

 band, a selection of 5 reply frequencies and 27 unique command codes may be 

 set by internal switches. Transmit, receive, and release functions are 

 powered by separate batteries to reduce the possibility of a total system 

 failure and assure recovery. Power is applied to the transponding release, 

 upon either fresh or saltwater immersion, by external electrodes. The 

 transponder housing pressure rated to a depth of 1,000 m, and the release 

 mechanixm has a load capability of 2,000 lb. 



4. In situ current velocity data were collected using an ENDECO, Inc., 

 Type 174 Digital Recording Tethered Current Meter. The 174 is an axial flow, 

 ducted impeller current meter, which is self-contained and records sampled 

 data on a 1/4 -in. magnetic tape. The instrument samples and records current 

 velocity and direction, as well as water temperature and conductivity, at 

 preselected intervals. It is normally deployed attached to a vertically 

 buoyed 3/16- to 1/4- in. stainless steel wire rope, held taut by a subsurface 

 buoy. The instrument is attached to the wire rope by a braided line 

 terminated by a unique clampling device, known as a "Cook Cable Clamp 



A3 



