382 UNDERWATER WEATHER STATION 



DIVER LOG, AUG. 28, 1965 TO SEPT. 11, 1965 



1st Day 



No current observed on the bottom. Visibility 30 ft (porthole covers still on; all observa- 

 tions today by divers). Two-in. nylon mooring lines sway slightly with the surge, estimate 1-ft 

 swing. No ripple marks in the silt and sand bottom sediments. Temperature outside about 



46°F. 



2nd Day 



Removed four starboard porthole covers. Visibility 30 ft. Current observations by diver- 

 onshore very slight. Observations through Sealab porthole— trajectory of plankton past glass 

 port is onshore and up. Trajectory interrupted by a pause about every 6 sec, during which 

 plankton "sinks" down, followed by a repetition of the onshore and up motion. Net drift onshore 

 and up at the rate of 1 ft per 15 sec. This condition prevailed all day. However, sometimes 

 in the late p.m., the direction reversed and plankton moved offshore and down. 



3rd Day 



No observations this date from inside Sealab. Observations outside show very slight drift 

 of plankton in a downslope and southwest direction most of the day, stronger by dark. 



4th Day 



Net drift of current onshore and up. Plankton moves 24 in. in 15-1/2 sec in the a.m. Cur- 

 rent decreased in velocity by noon, increased steadily in p.m. to offshore, 24 in. in 10 sec by 

 dark. Current increased near sunset and was strongest at 1800. Current velocity changed 

 very quickly after dark to a very slight offshore and down movement. There is still no distinct 

 off and onshore surge as is commonly associated with the passage of surface waves. However, 

 about 1800, 1 could "hear" or distinguish the pressure fluctuations associated with the passage 

 of surface waves. This was verified by topside watch officer. This p.m. was the last time I 

 was able to "hear" the pressure change of surface swell. This is probably because of bad hear- 

 ing caused by humidity and ear infection ( ?) or low waves. 



5th Day 



In the a.m. net current drift was offshore, very mixed and erratic, from high waves on the 

 surface last night ( ?). Plankton move offshore and sink most of the time. Same condition pre- 

 vailed all day, current strongest at dark or about 1800. One observation at 2200 shows slight 

 offshore current, plankton sinking down. Low waves, no surge, just steady offshore. Visibility 

 was very good today, and there was no indication of high waves. 



6th Day 



Wind chop on surface following 8-10 ft swell reported at surface. 0800— no current; 0900— 

 slight current flowing to the north and onshore about 0.1 knot; 1000— current increasing, surge 

 has on and offshore orbital motion, net drift onshore, orbital diameter 4-6 in.; 1030— current 

 increased, net displacement of 4 in. onshore during each cycle of the orbit; 1045— steady on- 

 shore or northern drift broken by irregular periods of 10-12 sec of offshore surge. Net is on- 

 shore about 15 in. in 15 sec. All offshore motion is erratic. Note: Fish (scorpion or Scorpina 

 Gattata) orient into the current, as a rule, unless feeding or moving which is about two to four 

 times a day. Other small fish, 1/2 cm-1 cm long, and some large migratory fish have no ob- 

 vious orientation preference so far as current direction is concerned. 1057 — slight onshore net 

 drift. 



