actual fuselage center. Further, the arrangement of the dP3, dP2 and 

 dPA diaphragms within the fuselage is such that they are not 

 precisely aligned with the x- or y- axes respectively. This design 

 was the result of space allocation problems within the top of the 

 fuselage. The errors are such that the sensor alignment of dP2 is 

 91°, 178° for dP3, and 269° for dP4 with respect to dPl = 0°. It was 

 considered that these one and two degree errors were negligible for 

 the present investigation. 



2. Height of Sensors 



Once again due to practical space allocation, the instrument 

 was designed such that the center isolation diaphragms are nine 

 inches (22.9 cm) above the arm diaphragms. The pressure response 

 function is developed during data analysis for the mean of these two 

 elevations above the seafloor. In 20 feet of water, the error 

 between the pressure response function for the actual sensor height 

 and the mean sensor height is less than two-and-one-half percent for 

 the highest wave frequencies of interest (periods of 3.1A seconds) 

 and less than one percent for wave periods greater than four seconds. 



