TRANSPORTATION OF FISHERY PRODUCTS 319 



the case of carload lots the shipper usually supplies the ice for the precooling and 

 initial reicing of the car before it leaves his plant. Salt is rarely, if ever, used in 

 precooling or reicing fresh-fish cars. 



In the case of less than carload lots the boxes of fresh fish are sometimes 

 covered with fine ice after being placed in the express refrigerator car. This is 

 done to reduce the melting of the ice in the boxes, especially in hot weather 

 and when the car is to be opened rather frequently. 



For packing the fish, however, it is claimed (Bulletin Fifteen, Flak Ice Corpora- 

 tion of New York) that "Flak Ice" has some advantage over crushed ice: it lasts 

 longer than crushed block ice; effects lower temperatures more quickly and 

 maintains them; handles more easily; is not injurious to the surface of the fish 

 because of its flat shape; presents greater contact surface to the fish since it has no 

 sharp projections; and has a greater heat-absorbing capacity for a given volume. 



This last claim is made on the assumption that the "Flak Ice" will be colder 

 (will have given up some specific heat as well as latent heat) because there is no 

 need for crushing; whereas the crushed ice may be wet and will, therefore, have 

 gained some of its latent heat. It would not be valid if both forms of ice were at 

 the same temperature when tested, unless the "Flak Ice" were more dense. This is 

 quite possible in view of the wide variation found in the density of crushed ice. 

 Variations between 26 and 42 pounds per cubic foot are said to have been found 

 with crushed ice, depending upon particle size; whereas "Flak Ice" is said to have 

 a density not varying greatly from a mean of 32.5 pounds per cubic foot. It would 

 seem that a more reasonable comparison of cooling capacities could be made on 

 a poundage basis. 



Apart from anv advantages that might arise from calorific capacities, the flake 

 type of ice does seem to have advantages for the icing of fresh fish. At any rate 

 "Flak Ice" and two modified forms of the same type, called "Pak Ice" and "Belt 

 Ice," are gaining favor in the fishing industiy. 



"Pak Ice" is made in the form of fine crystals, resembling coarse snow, and is, 

 therefore, soft and easy to handle. A full description of the method of production, 

 applications in industry, and modifications in forms suitable for storage will be 

 found in articles about the "Pak Ice Machine" (Anon., 1939, and Taylor, 1931). 



"Belt Ice" is almost identical with "Flak Ice," but the machines which produce 

 it make use of metal belts in a manner slightly different from the system employed 

 in the "Flak Ice" machine. The product has all the characteristics of "Flak Ice." 



Although there are no standard dimensions for the various sizes of wooden 

 boxes used for fresh fish, the dimensions used by several fishing companies on the 

 Canadian Pacific Coast are given in Table 83. 



Table 83. Some Relations Between Weight of Fresh Fish and Size of SmppiNG 



Box ARBITRARrLY UsED. 



, „ ,11.. -1 TTi r Outside dimensions 



Nominal Spice Additional Volume or , , , , 



, r t r 1 or box used by sev- 



weight or required space ror box i c i- 



^ . r f. 1 . J J era! fishinff compan- 



nsh for fish ice recommended ■ ■ >> j 



les in Canada 



(lbs.) (cu. ft.) (cu. ft.) (cu. ft.) (inches) 



75 1.5 0.75 2.25 30}^ X 15 X 10 



100 2.0 1.0 3.0 34 X 19 X 10 



1.50 3.0 1.5 4.5 40 X 19 X 12 



200 4.0 2.0 6-0 42 X 20 X 15 



