FILTERING UNIT 



WINCH 



TOWED UNIT 



1" I.D. Hose 



Depressor' 



Figure 1. --Schematic drawing of the towed pump and shipboard filtering unit as it is installed on the research 

 vessel Black Douglas. The arrows indicate the path of water through the system. From the funnels it flows 

 through drainpipes to the scuppers of the vessel. The collector is drawn larger than scale size. 



Both the support cable (1/4-inch stainless 

 steel aircraft cord) and the powerline (#14, 

 3-conductor, type S.O. neoprene cord) run 

 unattached inside the hose. All three elements 

 extend from a lower terminal connected to 

 the bridle in which the collector is mounted 

 to an upper terminal on the winch. Approxi- 

 mately 100 feet of hose is beyond the guide- 

 wheel when the system is set for towing. 



The winch is about 10 feet forward of the 

 fantail, and the filtering unit is about 60 feet 

 forward of the winch. They are connected by a 

 70-foot length of 1 1/2-inch I.D. thick-walled 

 polyethylene hose. The filtering funnel inlets, 

 about 11 feet above sea level, are the highest 

 points in the system. The swinging davit with 

 block and tackle, located just inboard of the 

 guidewheel, is used to set and retrieve the 

 collector. 



A detailed description of the system fol- 

 lows. 



The Collector 



Figure 2 is a photograph of the collector 

 mounted in the bridle and connected to the 

 lower terminal assembly of the hose-cable 

 suspension. The collector is secured in a heavy, 

 steel ring clamp with a pin on each side. The 

 pins project through holes in vertical plates 

 welded to the inside of the rigid diamond- 

 shaped bridle and function as an axle. The 

 bridle is suspended from a connecting rod 

 projecting from the bottom of the hose-cable 

 terminal assembly, and a 43-pound homo- 

 geneous depressor (California, State of, Marine 

 Research Committee, 1950) is in turn sus- 

 pended from the bottom of the bridle on a 

 short length of chain. The pump outlet is 

 coupled to the terminal assembly by a trailing 

 loop of 1-inch I.D. thick-walled rubber hose. 

 The powerline for the electric motor also 

 forms a loop between the collector and the 

 point where it enters the hose-cable terminal 

 assembly. Though not visible in the photograph, 



