Since the A-sheet is used on deck while 

 occupying a station, it is recommended that it 

 be secured to a clipboard with rubber bands. 

 Upon completion of all entries and calculations, 

 the sheet should be filed in the manila station 

 folder. 



14-8 THE LOG SHEET.— A sample log 

 sheet is shown in figure 14-2. Entries to be 

 made under the log sheet headings are recorded 

 as follows. 



14-9 Cruise No. — The survey cruise number 

 is assigned by the instructions for a specific 

 cruise. On surveys conducted by U. S. Navy 

 ships, a code prefixes the cruise number. This 

 code is used to identify the ship on all log 

 sheets, graphs, slides, records, and samples. 

 For example, the 15th cruise of the U. S. S. 

 REHOBOTH (AGS-50) is recorded as RE-15. 



14-10 Station No. — Oceanographic stations 

 are numbered consecutively as taken, starting 

 with numeral one for the first station of each 

 cruise. Thus, the complete identification for 

 the 34th station of the 15th cruise of the U. S. S. 

 REHOBOTH (AGS-50) is RE-15-34. 



A station is any group of oceanographic ob- 

 servations made at the same, or virtually the 

 same, time and geographic position. It usually 

 consists of one or more Nansen bottle casts, 

 plus possibly a bottom sample, Secchi disc 

 readings, plankton samples, wave staff record- 

 ings, submarine photometer measurements, 

 underwater photographs, microthermal depth 

 measurements, current measurements, meteor- 

 ological observations, etc. 



14-11 Vessel. — Give the full name and 

 number of the ship on each log sheet. 



14-12 Date. — Record the day, month, and 

 year. Use the Greenwich date of the starting 

 time of the station. This is the time the first 

 Nansen bottle is attached to the wire, as re- 

 corded in the Start column for the first cast. 



14-13 Cast. — Any series of instruments, 

 such as Nansen bottles, quantitative plankton 

 samplers, current meters, etc. which are sus- 

 pended at various depths along the oceano- 

 graphic wire to obtain more or less simultaneous 

 observations and samples is referred to as a 

 cast. Two or more casts are usually required 

 to obtain the desired data. 



14-14 Wire Angle. — The wire angle is the 

 angle between the oceanographic wire and the 

 vertical. It is measured from the instrument 

 platform when a cast is down. Just before the 

 messenger is dropped to trip the Nansen bottles 

 the angle is measured with a wire-angle indi- 

 cator. 



14-15 Greenwich Mean Time. — Record all 

 times for each cast in Greenwich mean time 

 (GMT) as follows: 



(a) Start is the time the first Nansen bottle 

 is placed on the oceanographic wire. 



(6) Down is the time when the case is lowered 

 to the desired wire depth and the winch is 

 stopped. 



(c) Mess, is the time when the messenger, 

 which is placed on the wire to trip the first 

 Nansen bottle, is dropped from the instrument 

 platform. Allow a minimum of 6 minutes to 

 elapse between the dowji time and the time 

 the messenger trips the first bottle. This is to 

 permit the reversing thermometers to come to 

 temperature and the Nansen bottles to flush. 

 The time required for a messenger to drop may 

 be figured at 200 meters per minute for wire 

 angles less than 35° and at 150 meters per 

 minute for wire angles greater than 35°. 



(d) Up is the time the last Nansen bottle is 

 tripped and commence hauling in the cast. 



(e) In is the time that the last Nansen bottle 

 or instrument of the cast is removed from the 

 wire. 



14-16 Latitude and Longitude. — The posi- 

 tion of the station is obtained from the adjusted 

 ship's track on the smooth plotting sheets. The 

 Start time of the first cast is used to determine 

 the time of the position. Record latitude and 

 longitude in degrees and minutes indicating 

 north or south (N or S) and east or west (E or 

 W), respectively 



14-17 Sonic Depth. — Immediately after the 

 ship has stopped on station obtain the sonic 

 depth and record it in fathoms and meters. 

 To convert fathoms to meters, refer to table 12. 

 Check the depth before each cast. If the bottom 

 is very irregular, frequent soundings while on 

 station are recommended, especially when in- 

 struments may be near the bottom. 



14-18 Max. Sample Depth. — The maximum 

 sample depth is recorded with two digits. It is 

 not entered until all values on the A-sheet are 

 computed and recorded. It is obtained from 

 the greatest bottle depth as shown in the Ac- 

 cepted Depth column and is given to the maxi- 

 mum 100 meters. For example, if the greatest 

 Accepted Depth is 2153 meters, record it as 21; 

 for 565, record 05; for 321, record 03. 



14-19 Type of Bottom. — Whenever a bot- 

 tom sediment sample or core is taken on station, 

 the type of bottom is recorded using the code 

 given in table 7. If no sample is obtained leave 

 it blank. 



14-20 Anemometer Ht. Above Sea. — For 

 ships equipped with anemometers, record the 



140 



H. O. 607 



