maxima of 117, and remained at this fairly stably until about 1400 hours, 

 at which time the level returned to 102 dB with maxima of 104. The ink 

 trace at this point was very faint so details of the level variation during 

 this period are not observable. The absence of an accurate time reference 

 after Thursday, 22 January makes it impossible to state the times with 

 much accuracy. The times are all estimated on the basis of the time mark 

 at the start of the run on Monday, 19 January and the assumption that the 

 nominal chart speed of 10 cm per hour was accurate. 



The major noise increases were related to work boat activity nearby. 

 The "Brazos Sea Horse", a 200 foot work boat, raised the level to about 

 115-116 dB with a maximum of 119. While it was maneuvering nearby it 

 raised the level to 123 dB with a brief peak at 132 dB. The "Tiger-Shark," 

 an 80 foot boat with twin engines, produced levels of 120-130 dB with a 

 maximum of 132 while maneuvering nearby. A somewhat similar vessel, the 

 "Tap Tide," produced levels of 110-130 dB, also with a 132 dB maximum while 

 it was maneuvering near the platform. 



From the above, rather limited data, it would appear that the sounds 

 of the drilling operations from platform Hondo are relatively stable, but 

 that substantial increases in local noise occur during the times of 

 arrival, departure and maneuvering of support boats. 



F-10 



