systems, the Wiancko system is considered somewhat more adaptable 

 and versatile than the others, since it is light and compact and can 

 be used from an anchored ship. It can be lowered to and raised from 

 the sea bottom by hand if the depth is not too great, whereas both the 

 acoustic system and the Mark IX require major placement operations 

 and become increasingly difficult to install as the water depth increases. 

 The three systems have been operated satisfactorily at depths of 50 

 to 75 feet, and all are capable of operation at depths of 30 to 200 feet. 



All three systems are fairly easy to calibrate and operate. The 

 Wiancko, for example, can be operated at a very high sensitivity; a 

 full-scale deflection can be obtained for one inch of water. However, 

 it operates best at full-scale deflections equal to or greater than five 

 inches of water. 



The acoustic system has been operated for two years, and the Mark 

 IX has been operated satisfactorily for periods of three months without 

 requiring recovery from the bottom. The Wiancko system has not been 

 tested for long periods of immersion, but such tests are now being 

 made at Fort Story, Virginia. It is recommended that these tests 

 continue to determine the total time that this system can be operated 

 without recovery and overhaul. 



The Wiancko system and the Mark IX are about equal in cost and 

 do not require elaborate or unusual instrumentation. The acoustic 

 system, however, requires a comparatively expensive initial outlay 

 but may have an overall longer life. 



The acoustic system is being improved continuously: The balancing 

 system is better, and the inclusion of a tide leak has given the system 

 a greater sensitivity. An improved model of the acoustic system is 

 being used by the Hydrographic Office at Fort Story, Virginia for a 

 detailed study of wave conditions on the East Coast. Further improve- 

 ments in the entire system, particularly in the bridge network, are 

 being continued. It is felt, however, that at the present time the 

 Wiancko system is more suitable for use by the Hydrographic Office 

 for short-term, shipboard operations because of its ease in handling, 

 installation, operation, and maintenance, and its moderate cost. 



2. Floating wave gauges 



The smallness of size and telemetering feature make the tele- 

 metering wave buoy (splashnik) preferable to long wave poles and any 

 wave measuring instruments that must be tethered to a ship by a con- 

 ducting cable. It is considered that the wave buoy also is probably a 



VII-16 



