The metal wave-gage holder is fabricated to the desired length as 

 shown in Figure 12; a list of components used in fabrication is shown in 

 Table IV. Mounting brackets for attaching the holder to the supporting 

 structure should be strong enough to support the holder during severe wave 

 conditions. Figure 13 outlines one type of bracket that has been used in 

 supporting the gage holder on a vertical piling. The gage holder gets two 

 coats of zinc chromate primer and two or three coats of anti-fouling paint 

 as used on ship bottoms. Government agencies may use this paint which is 

 available through Government Services Administration (GSA) supply - Stock 

 No. GS8010-550-8305 for the primer and Stock No. GS8010-290-6651 for the 

 anti-fouling paint. DO NOT PAINT THE GROUND ROD. Install the ground rod 

 after the gage holder has been installed. The holders should be installed 

 so that about 6 to 8 feet are below mean lower low water, 17 to 19 feet 

 out of the water. 



Only the epoxy wave gage sections that are below or at the water 

 line require anti-fouling paint. Mold release must be removed from the 

 gage sections prior to painting. DO NOT PAINT THE LEAD SENSING TIPS. 



3. Operation of a Series-Type, Step-Resistance Wave Gage 



a. Installation 



When placing the epoxy wave gage sections in the gage holder, 

 the section having the highest value resistors is the bottom section, and 

 goes into the holder first. The section with the next highest value re- 

 sistors is placed in the holder on top of this section, and so on until 

 the section having the lowest value of resistors is in the top of the 

 gage holder. 



The power unit, the strip-chart recorder, program clock, magnetic 

 tape recorder (if used) and chart rewinder are connected as shown on 

 Figures 14 and 15. 



b. Calibration 



The accuracy of the recorded wave heights will depend directly 

 on the accuracy of the calibration of the gage. There will be enough dif- 

 ference in each wave gage and in each strip- chart recorded to require that 

 each gage be individually calibrated. 



The ideal calibration would be raising and lowering the gage holder 

 with the gage sections into the water in small increments and marking the 

 strip-chart recorder with each move. Usually, lack of water depth, the 

 manual process required, and the presence of wave action prevent such 

 calibration. 



If many gages are to be calibrated, it may be desirable to provide 

 a cistern- like basin about 24 inches in diameter with the required depth. 

 A wave gage holder would be a permanent part of the calibration pit. Such 



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