OCEANOGRAPHY IN THE UNITED STATES 225 



In other cases, however, the oceanographic aspects of our problem are quite 

 novel and we are accordingly in a position to see the need for oceanographic 

 data that is incomplete. This can be illustrated by one of our current projects. 



We are engaged in choosing a site for what is called a sound range. This is 

 to be a facility for measuring ship noise. The facility consists of a number of 

 moored and anchored hydrophones along a course followed by the ship whose 

 noise is being measured. The site chosen for this facility must meet certain 

 oceanographic requirements. It must be quiet. That is to say there should 

 be a minimum of ship ti-afEc, the sea state should be low, there should exist a 

 minimum of noisy marine life such as .snapping shrimp and croakers, the micro- 

 scopic marine life should not fluctuate, and we do not want our otherwise wel- 

 come friend the playful porpoise and his ilk. 



Of course, we have other requirements besides quietness. We are interested 

 in the currents that cause our hydrophones to drift and thus make uncertainties 

 in the range with resultant errors in the measurement of the ship's noise. We 

 are interested in the thermal structure of our site and its daily and seasonal 

 variations, the bottom topography and its constitution, and many other properties 

 of the ocean. 



Some of the properties of the ocean in which we are interested are, of course, 

 rather peculiar to the science of underwater sound. For instance, we are very 

 much interested in scatters of sound. These scatters may be small bubbles that 

 exist in the surface layer or they may be small marine life. Their effect is to 

 scatter the ships radiated sound into the sonar system and thereby increase 

 the background noise. 



We understand that some research is in progress at our oceanographic institu- 

 tions on this small marine life that scatters sound. Our interest in this aspect 

 of the ocean is somewhat specialized and no doubt there are greater needs 

 than our own for this fundamental data. Yet. there is pointed up here again 

 the familiar fact that fundamental data can be used for a wide diversity of 

 purpose. 



Taylok Model Basin Disposable Wave Buoy (Splashnik) 

 (By Wilbur Marks) 



You have heard that we sometimes are compelled to develop our own instru- 

 mentation, in order to force the sea to give up some of its secrets. This is espe- 

 cially true in dealing with the sea .surface. Strangely enough there have been 

 more different wave measuring instruments developed than have been devised 

 for measurement of any other oceanographic parameter. The reason for such 

 a wide variety of instruments, all designed to measure waves, relates almost 

 entirely to the circumstances governing the experiment. In our case, we 

 wanted an instrument that would be easy to handle, would permit the ship to 

 go on about its business, would send information on the state of the sea back to 

 the ship, and would be cheap enough to eliminate the effort and cost (especially 

 to merchant ships) of seeking it out and retrieving it, after the experiment was 

 over. 



No existing instrument met all these requirements so we designed and built 

 the TMB Disposable Wave Buoy ourselves. As you can see, from its size and 

 shape, it is easily launched from the deck of a ship. Its development at the 

 time of the launching of the Russian Sputnik led to its nickname of Splashnik. 

 the seagoing satellite. Once it is afloat it bobs up and down like a particle of 

 water, re.sponding to the motion of the waves. As the ship starts its experi- 

 ment, the vertical motions experienced by the buoy are telemetered to the ship 

 via a miniature FM radio transmitter in the buoy. This information is returned 

 to the TMB analysis center where it is converted into a quantitative description 

 of the state of the sea. No matter how violent the sea, Splashnik is quite at home 

 in its environment. Its range is estimated at 11 nautical miles and 8 hours of 

 life. The cost per instrument is now $125 and expected to go still lower as com- 

 ponents are simplified. This nominal cost permits it to be considered expend- 

 able compared with the cost of locating and retrieving it. 



Our success with Splashnik has generated interest in oceanographic circles. 

 The U.S. Navy Hydrographic OflBce has expressed a desire for some Splashniks 

 to be used in a particular wave survey problem. The Dutch Government work- 



