8/| - 



Otherwise, an artificial phase lag may be introduced between the 

 sensors' readings. 



It was next decided to double the diameter of the long arm 

 tubings. This tactic decreased response time to about 0.12 seconds, 

 but the new 1/8 inch I.D. tubing was quite rigid. It was mated to 

 the original connectors by Swage-Lock® reducers with very short 1/16 

 inch I.D. tubings. The severe handling of the arm tubings during 

 back-filling and instrument assembly eventually led to the fracture 

 of at least two, and possibly three, of the reducers. Before the 

 failures occurred, the instrument was calibrated (Section V.C) , 

 assembled (Appendix D) , and brought to CERC under the pressure of 

 time for initial wave-tank testing. 



When the DPG was returned to the laboratory at the University 

 of Delaware, the arm tubing failures were confirmed and all of the 

 connectors and external tubing were replaced with flexible 1/8 inch 

 I.D. line and again back-filled with gin. The 1/16 inch I.D. nylon 

 tubing within the water-tight cylinder was not replaced. Response 

 time was recorded consistently as an acceptable 0.12 seconds, 

 (Section V.C), and the flexible tubing proved very easy to work with. 



