bucket. The "O" ring is just below the broad 

 slot in the bucket that allows clearance for 

 the tension screw of the steel clamp. As an 

 added precaution, a rubber baffle is attached 

 to the funnel just above the neck to keep the 

 "O" ring seal from being unnecessarily de- 

 luged by filtered water coming down the 

 outer surface of the funnel. 



The bottom of the bucket is covered by 

 105/i-mesh stainless steel cloth. When the fil- 

 ter is operating, this screen is covered by a 

 friction fitted cap so that all water filters 

 through the windows of the funnel. The cap is 

 twisted off at the end of a filtering period to 

 allow the small amount of water trapped in 

 the bucket and neck of the funnel to drain 

 out before the bucket is removed. 



OPERATION 



The collector is set for towing with the 

 vessel running slow ahead. The hook sus- 

 pended from the davit is placed in the top of 

 the diamond bridle frame, and the collector 

 is hoisted from its cradle on the deck and 

 lowered over the fantail until the hose-cable 

 terminal assembly is just below the guide 

 wheel. The hose is set in the guide wheel, and 

 slack is taken up by the winch. The hook is 

 then removed from the bridle, and the collec- 

 tor is lowered to a depth of a few meters below 

 the surface. The pump is turned on and, after 

 water is flowing satisfactorily through the 

 hose to the laboratory, the hose is reeled out 

 slowly. When the desired length of hose is 

 out, vessel speed is increased to cruising. 



The collector is retrieved by the reverse 

 procedure. When the unit is to remain aboard 

 for any length of time the entire system is 

 flushed with fresh water. The nose cone and 

 nozzle are removed from the collector, and a 

 fresh-water hose from the vessel is coupled 

 directly to the pump intake. Water is allowed 

 to run through the systemfor about 15 minutes. 



Once set, the collector is towed and the 

 pump operated continuously for the duration of 

 a survey. The longest continuous runs so far 

 have been approximately 72 hours. When 

 samples are not being collected during such a 



run, water is diverted to the scuppers through 

 the valve between the winch and the filtering 

 unit. 



The sampling patterns carried out in the 

 fall of 1961 required that sequences of 1-mile 

 samples be taken for one to a few hours with 

 interim nonsampling periods of one-half to 

 several hours. The 1-mile sample intervals 

 were taken to be equivalent to 6.5-minute 

 time intervals at vessel cruising speed, which 

 was estimated to average 9 knots. Samples are 

 easily collected by one operator under this 

 regime. The procedure followed is outlined 

 below: 



1. A few minutes before arriving at the 

 starting point of a sampling sequence, re- 

 move the collecting bucket from one funnel 

 (B), and close the diversion valve so that the 

 flow of water is directed to the filtering unit. 

 Set the double-throw valve so that the water 

 flows through the open funnel. 



2. Upon arrival at the starting point, switch 

 on the interval timer (an electric device 

 that gives an audible signal every 6.5 minutes), 

 record the watermeter reading and set the 

 double-throw valve to direct water into 

 filter A. 



3. Put the collecting bucket back on funnel B. 



4. When the timer rings again, switch the 

 valve to funnel B and record the watermeter 

 reading. 



5. Twist the friction cap clockwise off the 

 bottom of the collecting bucket on funnel A 

 and allow the residual water in the funnel to 

 drain through the bottom screen. 



6. Twist the bucket counterclockwise off 

 its bayonet mounting. 



7. Wash the sample from the bucket into a 

 jar with a gentle stream of water and a spray 

 gun. 



8. Fill the jar with water and the necessary 

 amount of formalin to make a 4-percent 

 solution. Label and cap the jar. 



11 



