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MARINE PRODUCTS OF COMMERCE 



blow-down valve is located at the bottom to lower the accumulating stickwater 

 below the oil outlet. The blubber is not hogged, but deposited in large chunks of 

 10 to 20 pounds or so. About every 3 feet the mass of blubber is separated by 

 steel grids which are placed within as filling proceeds. This prevents the contents 



(Courtesy U. S. Coast Guard) 



Fig. 33-3. Whales are pulled up the ramp of the factory ship by 

 a winch-operated cable and whale claw. 



from "balling up" and blocking the penetration of steam with subsequent building 

 of extremely high pressures. Cooking takes about 18 hours, and the oil flows off 

 continuously as long as the stickwater and graks are blown off below the level of 

 the oil pipe. When finished, the graks are removed by hand from the bottom, the 

 grids and digester cleaned, and another batch deposited. Pressure should be less 

 than 60 pounds per square inch because higher pressure means higher tempera- 

 ture with subsequent scorching of the oil and raising of the free fatty acid content. 

 This grid-digester method is the least efficient of the three as it takes a long time 



