the platforms would provide valuable data at very 

 small additional expense. Further, data describing 

 biological degradation of moorings and hull struc- 

 tures will be required in developing planning 

 factors for reliability and maintenance require- 

 ments. 



Recommendation: 



The National Data Buoy Development Program 

 should be pursued vigorously. The Program pro- 

 vides for tests of alternative buoy hardware con- 

 figurations, and different network spacings before 

 a commitment is made to a major operational 

 system; many of these tests can be conducted in 

 support of major oceanographic research efforts 

 (cf. Chapter 6). 



II. MOVING PLATFORMS 



Moving platforms for the collection of ocean- 

 ographic data include ships and drifting buoys. 

 Ships on oceanographic cruises have traditionally 

 provided the bulk of oceanographic data for 

 research. For the purposes of collecting data on a 

 synoptic basis, i.e., at many points at the same 

 time, the principal concern is with ships of 

 opportunity— ships at sea for purposes other than 

 oceanography that can collect useful data on a 

 not-to-interfere basis. 



Drifting buoys have long been used in such 

 primitive forms as drift bottles to gather ocean- 

 ographic information. Current technology makes it 

 possible to use such buoys to collect data which 

 would be transmitted via satellite relay. 



A. Ships of Opportunity 



Cargo, research, naval, and fishing ships offer 

 relatively cheap sources of good data and should 

 be fuUy exploited. Fully automated data collec- 

 tion devices are most desirable for fishing and 

 commercial ships to permit their operation by 

 personnel who are not technically trained. The 

 equipment should not interfere with normal ship 

 operations. 



Obtaining useful data from the surface waters is 

 relatively simple. It is technologically feasible to 

 automate the monitoring of a number of im- 

 portant parameters including temperature, salinity, 

 chlorophyll, and certain nutrients. The collection 

 of samples through the use of towed devices such 



as the Hardy Recorder or by sampling through hull 

 penetrations is also feasible. For more than 15 

 years the British have used the Hardy Continuous 

 Plankton Recorder on North Sea steamers to 

 obtain data valuable in managing the area's herring 

 fisheries. Obtaining information about the sub- 

 surface waters from a ship underway is consider- 

 ably more difficult. The recent development of the 

 expendable bathythermograph (XBT), however, 

 has pointed the way to the possibility of a family 

 of sampling devices for use from ships cruising at 

 high speed. 



1. Expendable Bathythermograph 



The needs for temperature-depth data in sup- 

 port of many operations, particularly the predic- 

 tion of sound propagation conditions, have been 

 discussed previously. Until recently, this data was 

 collected by means of the mechanical bathyther- 

 mograph, which records a temperature trace as a 

 function of pressure. Use of this instrument has 

 provided valuable insight into ocean temperature 

 structure. The ship's speed was restricted during 

 the lowering and retrieval of the instrument. 



Figure 17. Launching an expendable bathy- 

 thermograph. 



Collection of these data is now facilitated by 

 the development of the expendable bathyther- 

 mograph which can be launched by a ship under- 

 way, with no speed restriction. Although the 

 instrument is lost in collecting the data, quantity 

 production has resulted in a reasonable cost. The 

 probe remains cormected to the ship by wire, 

 ruiming off two spools, during the data collection. 

 Aboard the ship the data record provides a 

 temperature depth profile. A small computer can 



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