NOTES REGARDING OCEANOGRAPHY 



In discussing the details of oceanographicwork such 

 as that included in the program of the seventh cruise of 

 the Carnegie , a major item to be mentioned is the taking 

 of water samples at various depths from the surface 

 down to 10,000 meters. This operation requires, as 

 equipment, bronze cable, preferably graduated in size, 

 and ample power to handle it, along with maximum ma- 

 nueverabilityof the vessel. It also demands a large sup- 

 ply of reversing water bottles, deep-sea reversing ther- 

 mometers, and messengers. Another operation of im- 

 portance is bottom sampling. An innovation, which was 

 to have been tried by the Carnegie and which seems 

 worth recommending to others, was to be the use of a 

 light and small water bottle on the bottom sampling line 

 a short distance above the bottom sampler. The water 

 bottle was to be reversed by a propeller arrangement 

 similar to that of the Sigsbee thermometer reversing 

 frames. A few such bottles had been made for the Car- 

 negie but, as they were received the day before the ship 

 was destroyed, there was no opportunity to try them out. 

 A separate winch equipped with piano wire is desirable 

 for getting bottom samples. 



A third operation is trawling, which is necessary in 

 connection with the biological work. This requires a 

 winch of considerable power. Even so, the size of 

 trawls and dredges must be limited to fairly small units 

 when this work is carried on in great depths. Plankton 

 and the smaller forms of marine life are caught with 

 silk townets. Vertical and horizontal tows are made, 

 and in the latter case several nets can be attached to the 

 same line at various levels. The Pettersson plankton 

 pump is used for quantitative studies, but, aside from its 

 other mechanical defects, it has the disadvantages that 

 the volume of water pumped is more or less uncertain 

 and that the more rapidly moving organisms are not 

 caught by it. The U. S. Coast and Geodetic Survey sound- 

 ing txibe works very well for determining net depths in 

 plankton work. While the vessel is under way, small 

 nets are used for diatom tows at the surface; while in 

 port or in shallow water, the small Mann bucket is use- 

 ful for diatom dredging. The ordinary dip net is a very 

 handy device at all times and for a variety of purposes. 



Experience indicates that it is very desirable that a 

 hard and fast schedule be avoided, that is, it should be 

 sufficiently flexible to allow the vessel to be stopped to 

 develop more fully an interesting or unusual section and 

 to verify unusual results. This applies with equal force 

 to the physical, chemical, and biological fields. In bio- 

 logical work, night stations are fully as important as day 

 stations, and probably more valuable than either would 

 be a twenty-four-hour station. 



Inasmuch as the details and technique of manage- 

 ment of a sailing vessel when hove to for the collection 

 of deep-sea samples are of interest to those contemplat- 

 ing an oceanographic expedition in such a vessel, and as 

 published data covering the experience of previous ex- 

 peditions are rare, it seems advisable to note here, even 

 if briefly, some of the problems encountered and prac- 

 tices resorted to on the nonmagnetic ship Carnegie . The 

 Carnegie was a wooden auxiliary brigantine of about 568 

 tons displacement, carrying fore course, lower and up- 

 per topsails, gallant, and royal on the foremast; a single 



club-mainsail on the mainmast; main, middle, and upper 

 staysails; and fore-topmast staysail, inner, outer, and 

 flying jibs forward. Her auxiliary power was small and 

 was furnished by a lOO-horsepower gasoline engine 

 driving a single screw, and capable of producing a speed 

 of six knots under conditions of dead calm, smooth sea, 

 and no swell. A single winch powered all lines and was 

 located on the quarter-deck. This winch carried two 

 reels of aluminum bronze cable, a reel of steel piano 

 wire, and two gypsyheads. The piano wire led directly 

 to a sounding davit at the stern and was used for bottom 

 sampling. The bronze cables led through blocks at the 

 mainmast to sounding davits on either side of the quarter- 

 deck somewhat forward of the winch. One line was used 

 for reversing water bottles and the other for the plank- 

 ton pump. Silk nets were put out forward and their line 

 brought aft through suitable blocks and manipulated by 

 means of one of the gypsyheads. Thus it will be seen 

 that a maximum of four lines were out at one time, two 

 of them shallow and two deep. The problem was to keep 

 the lines as nearly vertical as possible and to prevent 

 their fouling one another. Three elements had to be con- 

 sidered, namely, wind drift, current drift, and the vessel 

 falling off and coming up. In general, the Carnegie was 

 hove to under mainsail and backed lower topsail. De- 

 pending on conditions, more of the fore-and-aft sails 

 were set or more of the square sails were backed as re- 

 quired. The water-bottle line ordinarily was led to the 

 windward davit to insure the line leading away from the 

 vessel instead of leading under it, although in some 

 cases of unusual currents the use of the leeward davit 

 was necessary to obtain the desired result. Because of 

 the difference in loading of the various lines and because 

 of their differing resistances to motion through the water, 

 the different lines had different wire angles. Of the three 

 lines put over from the quarter-deck, generally the piano 

 wire had the greatest angle, the plankton-pump line had 

 the next greatest, and the water-bottle line had the least. 

 The pump line, however, was sometimes more nearly 

 vertical than the water-bottle line. This variation was 

 due largely to the fact that the pump line was always con- 

 fined to the upper one hundred and fifty meters and hence 

 was subjected, for the most part, to only the surface cur- 

 rent, whereas the water-bottle line extended down below 

 the surface current in most cases. The relative angles 

 of the two lines consequently were dependent on the ve- 

 locity and direction of the surface current with respect 

 to the wind. Often the surface current is moving with the 

 wind; under this condition the wire angle can be expected 

 to increase with the depth to which the line extends after 

 the end of the line has penetrated below the surface cur- 

 rent. This, if for no other reason, is because the deeper 

 the line beyond the limit of the surface current, the 

 greater the anchoring effect or resistance to horizontal 

 motion afforded by the subsurface layers. It will be 

 seen, then, that the wire angle changes both in paying out 

 and hauling in, and that, consequently, care and judgment 

 must be exercised if the lines are to be kept from fouling 

 one another during such operations. Economy of time 

 would require that all lines be out simultaneously and 

 this was the practice on the Carnegie during the early 

 part of the cruise. Later the program was changed, at 



96 



