g» Wave Height Range: The instrument must be able to sense dis- 
placements from mean sea level of +20 feet, giving a total wave height 
of 49 feet. Resolution should be such that wave heights of $ foot or 
greater will be measured. 
he Period-Length: The instrument should be capable of sensing 
all variations in relative sea surface height which have periods between 
2 and 25 seconds. In terms of lengths, waves of from 20 to 2,500 feet 
should be sensed by the instrument. Should the sensor use as its operat- 
ing principle one which averages readings over a small area of sea sur- 
face, the area involved should be less than 5 feet in diameter. 
i. Durations The instrument should be capable of measuring the 
relative height of the sea surface as a continuing function of time. 
Although measurements of s hour duration will be required ordinarily, 
special problems will require records of many hours duration. 
j- Recording and Analysis: 
(1) Visible: A visible, strip chart record of wave height, as 
function of time, is required. This recording should be normalized, and 
should be of such a scale as to permit manual digitizing to the accuracy 
of the instrument at 3 second intervals. 
(2) In addition to visual recording, the wave data must be amen- 
able to spectrum analysis on board ship. 
(3) Electric or electronic sensor signals must be such as to permit 
the Master Shipboard Data Logging and Processing System to accomplish 
(1) and (2) above where this data logging and processing system is in- 
stalled. Where this system is not installed, separate computing and re- 
cording equipment must be available to accomplish (1) and (2) above. 
Potential Users and Estimated Number of Units Which They May Require: 
ae U. S. Navy (basic research, applied research, and oceanographic 
survey ships) - 20 to 30 
be U.- S.- Coast and Geodetic Survey - 10 to 15 
c. Certain activities of the scientific community - 10 to 15 
d.- U. S. Air Force Ocean Range Vessels - 6 to 8 
e. Bureau of Commercial Fisheries - 2 
f. U. S. Coast Guard - 15 to 30 
Totals: 63 to 100 
Recommendation Where Instrument Should Be Researched and Developed: 
U. S. Industry. 
