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easily be missed in times of unreliable atmospheric conditions, a state more 

 or less characteristic of sea ice boundary areas. Positions based on astronomi- 

 cal sights were frequently poor and loran coverage was incomplete. The eval- 

 uating of the character of the ice in terms of ships' operations required consid- 

 erable experience and familiarity of the capabilities of the different class ves- 

 sels. -A ship skipper sighting ice for the first time from the air almost always 

 overestimated what his vessel could do. After about three observation flights, 

 alternated with ship attacks on the ice, estimates began to have meaning. Aerial 

 observers not benefitting by shipboard experience learned more slowly. The 

 real need is to keep the physical description of the ice, in numbers where possi- 

 ble, keyed to the ice itself and independent of the observation aspect, vessel 

 capabilities and the like. Easily measured, easily understood and accurate 

 physical descriptions are needed. The ice observers instructions and ice codes 

 are a step in the right direction. 



Radar viewing shows targets the strength of which are, in part, a func- 

 tion of the performance level of the instrument and the prevailing transnnission 

 characteristics of the atmosphere. Because of these and other variables, radar 

 data is subject to serious misinterpretation. Successful scouting of sea ice 

 limits and outlying icebergs has been made while blind using radar and loran but 

 reliance is given here only to space and time extrapolation of visual sightings. 

 Visual and electronic photography, with suitable interpretation keys, can be ex- 

 pected to increase the usefulness of aerial scouting. 



Land and Ice Vehicles - The days of the individual assault on the sea ice fron- 

 tiers by kayak and dog sled, the primitive amphibious-ice vehicle, are at end. 

 A true ice-annphibian, however, light enough to travel over average ice but 

 strong enough to pull itself out of leads and "break-throughs" would favorably ex- 

 tend the field of action of any vessel, shore or ice station. As an independent 

 unit it would have limited range. For far afield operations it would need logis- 

 tic support, presumably by air. 



In winter, caterpillar tractors now operate on shorefast ice and the small 

 amphibious "weasel" has been successfully used on pack ice. The wide treads 

 of the latter permit rapid progress even across soft snow and comparatively 

 light sea ice. Several "snowmobiles" have been developed for winter travel on 

 land and some of these might be made amphibious. Presumably such a vehicle 

 could be fitted out in the manner of a small oceanographic vessel. Oceanograph 

 raphic instruments would be similar to those used for on-ice plane landings. 

 Here again the limitations are those of the vehicle. 



It might be mentioned that for small ice parties the powering of the 

 oceanographic winch presents difficulties. Hand power, foot power, wind pow- 

 er and various types of fuel powered, portable winches have been used. None 

 have been satisfactory in all respects, notwithstanding recent attempts to im- 

 prove them. 



Arctic Stations - Arctic stations, such as the Arctic Research Laboratory of 

 the Office of Naval Research at Point Barrow, the newer weather stations in the 

 Canadian Arctic Archipelago, and the Air Force station on T-3 all provide for 

 long continued observations of the "inshore" ice and weather peculiar to their 

 locations. Problems such as times of freeze-up and break-up, growth rate of 

 ice, ice-beach processes, and the effect of ice on tides can be investigated. The 

 more readily accessible stations are convenient for testing certain sea ice equip- 

 ment and making ice engineering tests. Although the stations are on the edge of 

 sea ice, the moving pack is by no means easily accessible. Effectively, it may 

 be as remote from the station as it would be from the interior of the continent. 



