88 



and Soule, 1933). Ready access would be provided through the ice 

 under most conditions. The observers and equipment would be pro- 

 tected from wind and weather and the temperature could be controlled. 

 With suitable modifications some gear might at times be streamed 

 underway. Depressors might be used to keep the line clear of the 

 propellors. 



(g) The observers and equipment on deck are normally on the weather 

 side and are exposed to the extremes of wind and temperature. Pro- 

 tection in the form of windbreaks, hot air ducts, and other devices 

 have only been partly satisfactory. At low temperatures ice forms 

 on the wire and prevents proper functioning of the messengers and 

 meter wheel. Ice coats on the outside of the reversing bottles and 

 interferes with their handling. Ice may also form in the bottles in- 

 creasing the salinity of the residual water. The messengers freeze. 

 Many of these difficulties can be alleviated by protecting the equip- 

 ment from the extremes of conditions as much as possible, as for 

 example, by making all preparations for sampling in protected spaces 

 and promptly returning the instruments to protection as soon as they 

 are removed from water. Equipment for cold weather operations 

 should be simple, rugged, reliable and designed to operate under ex- 

 treme temperature ranges. Manipulations should be possible with 

 mittens. Plastic bottles are now used for impounding water samples 

 and the thermal characteristics of plastics should make these mate- 

 rials desirable for other oceanographic equipment and gear. 



(h) A difficulty arising from the ice rather than the vessel is that non- 

 captive gear, for example salt ballasted underwater cameras, will 

 likely surface under ice and not be recovered. 



(i) Present ice breakers cannot efficiently disembark personnel and 



"on ice" vehicles that might be used for observations from the larger 

 floes. Suitable provisions for such disembarkation could easily be 

 made and would materially increase the scope of investigations pos- 

 sible. 



Heavy icebreakers have been used to only a small fraction of their poten- 

 tial capabilities in sea ice investigations. Much new data and knowledge can be 

 gained using but slight modifications in present techniques and equipment. 



Submarines - The use of submarines for oceanographic work in ice dates to 

 the NAUTILUS expedition conducted by Wilkins and Sverdrup in 1931 (Sverdrup 

 and Soule, 1933). Their original plans had been to cross the Arctic Ocean from 

 Spitzbergen to Bering Strait or, failing this, to reach the North Pole. The loss 

 of a diving rudder made travel under the ice impossible. Their goals were not 

 acheived but they did carry out significant oceanographic investigations within 

 the ice limits. Since that time submarines have operated in periphery areas of 

 both the Arctic and Antarctic packs. The use of the submarine in oceanographic 

 investigations is still restricted by the nnechanical linriitations and operational 

 capabilities of the vessel itself and not by deficiencies of oceanographic instru- 

 ments and methods. When the true submarine becomes available, it should be 

 able to do almost any oceanographic work that can be carried out by surface 

 vessels and do much of it easier. A "Jules Verne" class submarine offers the 

 following advantages: 



(a) Relatively free maneuverability is afforded in ice areas outside 

 the continental shelf, although not in shallow water between the ice 

 canopy and bottom. 



(b) The platform is stable. It has been extensively used for gravity 

 determinations at sea. 



(c) Effects of weather are reduced to a minimum. The roll of an ice 



