87 



1940. The wind-class ice-breakers (Fahey, 1945) commissioned during and 

 after World War II are the best available to us. These displace about 5,300 tons, 

 are 269 feet long, 63.5 feet beam, draw about 29 feet, and have 10,000 h.p. diesel 

 electric machinery. They can successfully navigate fringe ice areas the year 

 around, but are unable to move freely far within the Arctic pack at any time of 

 the year. Considerable penetration can be made locally in summer, and per- 

 haps greatly more on some years and in some localities than on other years and 

 in different localities. Larger and nnore powerful icebreakers are invariably 

 proposed. .These presumably would give greater freedom of movement in the 

 fringe areas and, given time and taking advantage of the summer conditions, 

 might be able to cover most of the Arctic Basin. Regardless of the size and 

 power of a surface vessel, however, it will not have comiplete maneuverability 

 in ice areas at all times, and progress with respect to the ice will always be 

 made at great expenditure of energy compared to operations in the open sea. On 

 the other hand, submarines operating under ice and aircraft flying across ice 

 areas do not make premium power demands. 



The use of modern icebreakers has increased the knowledge of ice condi- 

 tions both around the Arctic periphery and in the Antarctic. Within the ice, 

 these vessels provide a stable working platform, living space for scientists, and 

 a limited amount of laboratory space. Excellent electronic equipment and even 

 helicopters for ice scouting can be carried aboard. 



Some of the drawbacks of these vessels as oceanographic platforms are: 



(a) Requirements for personnel and power are high. 



(b) Complete maneuverability in ice is lacking. 



(c) The five-fathom draft of the heavy icebreakers requires that the ves- 

 sels keep well off shore in much of the Arctic, which is characterized 

 by the world's broadest continental shelf. 



(d) Their heavy roll prevents full efficiency in stormy weather outside 

 ice areas. Any bilge keels or other external hull devices to damp 

 the motion would need be retractable or they would be torn off by the 

 ice. 



(e) In heavy ice areas conventional oceanographic gear, such as dredges, 

 plankton nets and the geomagnetic electrokinetograph (GEK), cannot 

 be towed nor can bathythermographs be lowered under-way. A means 

 for handling these under-way devices in ice areas is needed. No 

 simple solution is apparent. 



(f) Under the influence of the wind, the icebreaker drifts with respect to 

 ice whenon-station, resulting in drifting ice fouling the hydrographic 

 line. Advantage can be taken of open areas when these are available. 

 The ship is oriented with the sampling platform upwind and the lee 

 side can be berthed on the windward side of a large ice floe to cut 

 down relative drift. Devices for keeping ice cakes out of the line 

 are needed. Prod poles, grapnels on a line, fire hoses, fenders 

 and even frogmen have been tried as circumstances indicated but no 

 simple solution has yet been found. A very sturdy retractable pro- 

 tective frame that could be lowered into the water at the beginning of 

 a station might aid considerably in the more open ice. This device 

 probably could not be used where lateral pressure is great or during 

 winter when the broken ice occasionally has the consistency of grav- 

 el, resisting or even preventing the lowering of gear. Large wire 

 angles experienced during strong winds also complicate protecting 

 the wire. A pressure compartment in the bottom of the ship that 

 could be opened to the sea for sampling purposes is worth consider- 

 ing. This might be somewhat sinnilar to the diving compartment of 

 the submarine NAUTILUS used by Wilkins and Sverdrup (Sverdrup 



