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C. E. LINDSAY 



of 4- by 4-inch angle iron and should be 

 embedded entirely in concrete, with only 

 the steel hold-down bolts extending above 

 the concrete surface. Plate hold-down 

 bolts must be spaced at intervals no greater 

 than 7 inches, and must be at least %-inch 

 diameter to eliminate flexing of the plate 

 and weakening of bolts by rust. 



Pumping throughout, the large tidal 

 range creates a variable suction head as 

 well as considerable variation in water 

 temperature and salinity. In order to 

 minimize these effects, the system was op- 

 erated by intermittent pumping, which 

 was as a rule done at any stage of tide 

 higher than half-tide. This minimizes 

 the danger of loss of prime of the pump, 

 but does not completely eliminate it. 

 Malfunction of the check valve regardless 

 of the stage of tide is also a factor in 

 loss of prime. Since funds were not 

 available for an automatic vacuum sys- 

 tem, we have used the fresh-water supply 

 as a source of priming water. This is 

 achieved by making direct connection be- 

 tween the main fresh-water line and the 

 main sea-water line so that an adequate 

 volume could be flowed directly into the 

 pipe or built up in the storage tank to 

 provide enough water for priming even 

 when the check valve was stuck wide open. 

 The pump control system is designed to be 

 either automatic or manual. When lines 

 were filled, repriming was accomplished 

 by switching electrical controls from auto- 

 matic to manual and allowing the pump to 

 refill the storage tank. 



In addition to the normal safety 

 switches for protection of the pump motor 

 in case of overload or low voltage, an inter- 

 locking safety switch and control system 

 was designed. An ordinary mechanical 

 float switch with styrofoam flotation was 

 used in the main storage tank to prevent 

 overfilling. A mercury switch, activated 

 by air pressure and connected to an open- 

 ended plastic pipe on the beach, was used 



to provide an adjustable tide-level switch. 

 In operation, as the tide recedes below a 

 predetermined level, this switch shuts oflp 

 the pump so that pumping cannot occur, 

 and as the tide rises, air pressure in the 

 line reactivates the switch so pumping can 

 occur on demand. To protect the hard- 

 rubber-lined pump from being nm with- 

 out water, an electric probe switch in the 

 suction screen box coupled to a relay pro- 

 vides positive protection against loss of 

 prime and prevents automatic restarting 

 of the pump following power outage. 

 This loss-of-prime safety switch has not 

 been entirely trouble free, but we have 

 found in practice that as long as it is 

 checked daily and cleaned occasionally, it 

 provides adequate protection for the 

 pump. 



Sea-water storage facilities, as men- 

 tioned in the beginning, initially consisted 

 of a single 10,000-gallon wood storage tank 

 placed on a hill at an elevation approxi- 

 mately 6 feet above the roof of the labora- 

 tory building. When full, it provided a 

 maximum head of about 15 feet. Since 

 antifouling paints, or applications of toxic 

 chemicals to prevent or remove boring 

 organisms would also jeopardize other in- 

 invertebrate animals, it was originally 

 planned to treat the tank periodically with 

 hot fresh water. However, the volume re- 

 quired to adequately treat the tank was so 

 large (4,000 gal.) that it was impractical 

 to use this approach. Partial protection 

 was achieved by coating the bottom with 

 high-melting-point roofing asphalt and the 

 walls with bituminous water-tank paint. 

 Later a polyethylene liner was installed to 

 achieve better protection of the tank walls. 

 In spite of these efforts, the walls became 

 so riddled with teredos {Banhia setaeea) 

 that the tank had to be replaced after 7 

 years' operation. 



A new 1.5,000-gallon concrete storage 

 tank was built adjacent to the original 

 wood storage tank. It was provided with 



