CURRENT METER FOR CONDUCTING COASTAL AND OCEANIC SUBSURFACE 
CURRENT SURVEYS 
Sketchs 
(To be provided) 
Primary Use: 
This is a precision instrument to be utilized on oceanographic 
survey vessels for conducting subsurface current studies and surveys 
in coastal and oceanic areas with the ship anchored or "lying-to”. 
It must measure and record precisely the direction and speed of the 
subsurface currents. 
Requirements and Specifications: 
ae To perform reliably and accurately on survey ships which are 
anchored or “lying-to". 
b. To be operable in depths varying from 0 to 6,500 fathoms with 
no adverse effects thereto due to hydrostatic pressure. 
ce To be so designed as to be utilized individually or in multiple 
groupings on one cast. 
d. To be so designed that the adverse effects of platforms and 
sensor motions (horizontal and vertical accelerations) are eliminated 
or minimized considerably. 
e. To be designed to include four (4) interchangeable, modular 
depth sensor units: (1) 0-600 feet, (2) 0-6,000 feet, (3) 0-15,000 
feet, (4) 0-39,000 feet. 
f. Depth accuracy for each module to be +4% of full scale. 
ge Current range and accuracy: 
(1) Speed: 0.05 kt - 8.0 kts3 +0.05 kt accuracy at readout 
(2) Direction: 000-3609; +10° accuracy at readout 
(3) Instrument output should be linear with respect to the 
current measured over full range of interest. 
(4) Time responses 95% response to speed step-function from 
zero to 1 knot in 1 second or less. 
