PART V - SUMMARY OF OPERATIONS (CONT) phosphates, and ammonia (frozen for later analysis ashore) and biological determinations of plant pigments, and productivity. B stations, twice daily between A stations, included 500 meter STD and hydrocasts, and oblique and surface plankton tows; chemical analyses were carried out as above. At C stations, occupied midway between the A and B stations, only expendable bathythermograph observations were made. A and B stations were generally separated by 42 miles so that the effective sampling inter- val was about 21 miles. (b) While underway, continuous observations for the majority of the cruise included depth, near-surface temperature and salinity, near- surface chlorophyll, incoming solar radiation, wet and dry bulb tempera- ture differences, three-hourly surface weather observations, and twice- daily upper air observations and, additionally, a survey of bird life was made including statistical count, identification, photography and specimen collection. (c) Between 5° North and 5° South and when within 100 miles of land 500 meter STD casts were made in lieu of the usual XBT observations at C stations, and midway between all stations XBT drops were made. This reduced the sampling interval in these areas to 10 miles. On the basic tacklines hydrocasts to as close to the bottom as possible were made every second day. Along transit legs (i.e., passages from one assigned tackline to the next) 300 meter STD casts were made every 20 miles. (d) A stop was made at Cocos Island to examine possible sites for the installation of a tidal gauge for the Bureau of Commercial Fish- eries. While ashore on the island, biological specimens were collected. (2) Performance of Oceanographic Equipment and Instrumentation. (a) The STD System. 1. The STD functioned efficiently throughout the cruise except for two failures which resulted in some lost data at five stations. The first casualty resulted from a loosened terminal within the tempera- ture sensing element, and the second from a slow leak in the depth sensor causing internal corrosion to such an extent that one of the printed cir- cuits had opened and had to be rebuilt. 2. The 1/4" galvanized steel electronic conductor cable served well during the cruise. It was reterminated several times to remove sections at the outboard end which exhibited signs of excessive wear. The remainder of the cable appears to be satisfactory in that there are no fish hooks, severe abrasions, etc. However, note must be taken of its age and the use to which it has been subjected. It is understood that Scripps Institution, on their oceanographic vessels, replaces this cable every six months to prevent the loss of the expensive STD unit. 3. The major problem with the STD system aboard the ROCKA- WAY is the location of the winching system. The winch is located on the O2 deck, port, at frame 73, and the A-frame and work platform is on the O1 deck. The sheave over which the cable runs is approximately 30 feet above the water and this, together with the tumble home of the hull, and