26 



U. S. COAST AND GEODETIC SURVEY 



Wafer surface 



64. On the other hand, a tide station located some distance from a 

 congested area, where the tide is equally representative of the general 

 region, will be freer from these disadvantages and be no less accessible 

 to the tide observer. In general, a Federal, State, or municipal wharf 



is preferable to a private one; but a pier 

 maintained for public amusement and recre- 

 ation often affords an ideal location for a 

 primary tide station. 



FLOAT WELL 



65. The float well is a vertical tube or box 

 with an opening in the bottom designed to 

 admit the tide to a float operating the gage 

 while dampening out the larger waves 

 caused by winds. The float wells now gen- 

 erally used by this survey are constructed 

 either of iron or of wood. For exposed loca- 

 tions on the outer coast the iron float well 

 is used on account of its strength, but for 

 more quiet w^aters a float w^ell con- 

 structed of wood and covered on the out- 

 side with sheet copper is more economical 

 in construction and installation and will 

 last many years. In cold climates which 

 require the use of kerosene in the well to 

 prevent freezing, the iron well has the ad- 

 vantage of retaining the kerosene without 

 leakage over a long period of time. 



66. Iron float well. — The iron float well 

 (fig. 14) is usually made up of sections of 

 stock pipe. The usual installation when the 

 depth is not too great consists of a support- 

 ing section below the intake and extending 

 several feet into the ground and containing 

 large openings in the sides to admit the tide 

 to the intake. Above the intake a suflficient 

 number of pipe sections are used to extend 

 the top several inches above the floor of the 

 tide house. A special intake coup/ling (fig. 

 15) forms a union between the supporting 

 section and the pipe above. If possible, the 

 section immediately above the intake should 

 be sufficiently long to extend above high 

 water in order that there may be no rough 



joints for the float to catch on and to provide an oil-tight section for 

 kerosene when this is necessary to prevent freezing. Flange cou- 

 plings may be used for connecting pipe sections above high water. 

 While such joints are not as durable as sleeve couplings because of 

 the tendency for the connecting bolts to corrode, they add greatly to 

 the convenience of installation and the bolts when above high water 

 may be easily renewed from time to time. 



67. For a primary tide station 12-inch pipe is recommended. Wheii 

 a supporting section is used, this should contain six large openings, 

 each about 3 inches wide by 9 inches long and arranged in pairs on 



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[L — Opening in 

 r supporfing pipe 







Sea bo from 



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FiGORB 14. — Float well. 



