not always adequate criteria. 
Operation and maintenance of both individual instruments and in- 
strument systems must not be so complicated as to require extensive, 
specialized training for their use. 
4. Instrument and instrument system power requirements must not 
necessitate elaborate voltage and frequency controls. 
5. Possibly the least understood and, yet, the most important is 
the fact that all of these instruments and instrument systems must be 
especially designed to be used at sea. Their construction and operation 
must be reliable, accurate, and compatible with the shipboard and marine 
environment which can be very severe on occasions. 
Inasmuch as all of the described instruments and instrument systems 
are to be designed for use aboard oceanographic survey vessels, the 
following general background information is provided regarding ship 
characteristics: 
1. U.S. Navy Length Beam Draft Displacement 
a. AGS 30 and 50 310 feet 41 feet 14 feet 2,800 tons 
b. AGS 18 Class 221 feet 32 feet 10 feet 1,221 tons 
c. AGOR SCB 185 208 feet 37 feet 15 feet 1,387 tons 
Class 
2. U.S. Coast and Geodetic Survey 
ae Class I Ships 300 feet 48 feet 20 feet 3,100 tons 
b. Class II Ships 210 feet 40 feet 15 feet 1,300 tons 
c. Class III Ships 150 feet 30 feet 10 feet 750 tons 
3. Bureau of Commercial Fisheries 
a. Coastal vessels 40 feet (various)(various) 150 tons 
to (approx. ) 
75 feet 
b. Short-range, 75 feet (various)(various) 600 tons 
offshore to (approx. ) 
vessels 125 feet 
c. €xtended-range,125 feet (various)(various) 1,000 tons 
ocean vessels to (approx. ) 
200 feet 
ikabat 
