(2) Constant stabilization to 1/2° of arc from the vertical. 
(3) Minimum lag in stabilization action, easy accessibility 
for maintenance. 
(4) Alarm system to detect malfunctions. 
f. Receiver - transmitters 
(1) Frequency: 10 - 18 KC 
(2) Transmission: Pulsed CW emission and reception. 
(3) Frequence Control: Precise intermediate frequency (IF). 
(4) Scale Range: Several and concurrently shifted. 
(5) Phasing: Automatic phase detection. 
(6) Pingings Single or continuous. 
(7) Outputs: Output suitable for audible depth indication and 
use with an external precision recorder. 
ge Recordings 
(1) Data Display: To present travel-time data to a display 
which automatically connects horizontal and vertical components and 
displays data from successive sweeps as contours at pre-selected in- 
tervals varying between 5 - 100 fathoms. 
(2) Data Recording: Output data to be compatible to present 
and planned data reduction methods. 
(3) Must record continuous bottom profiles in addition to 
plotting "contours". 
(4) "Alternate" Recorders 
(a) Paper Width: 18" 
(b) Time Accuracy: 1 part/million 
(c) Paper Speeds: 24 and 72 inches/hour and also geared to 
own ship's speed for various chart scales. 
(d) Marking area of recorder paper to have accessibility 
for ease of immediate reading of trace. 
(e) Adjustable for setting correction for ship's draft. 
(f) Provision for a gating circuit. 
(g) Means for a numerical depth print-out. 
(h) Means for changing vertical scale of recording. 
(i) Automatic depth phase recording on trace. 
(j) A reflectivity meter should be built into the system to 
provide a continuous recording of the reflectivity of the sea floor. 
Potential Users and Estimated Number of Units Which They May Requires 
ae U. S.- Navy (hydrographic-oceanographic survey ships, basic re- 
search ships, and applied research ships).- 19 to 25 
b. U- S- Coast and Geodetic Survey - 2 to 6 
c. Certain activities of scientific community - 10 to 15 
