THE CRANBERRY INDUSTRY 11 



Table 5. — Massachusetts Cranberry Bog Pumping Plants in 1934 



"Lift," as used in the survey, is the difference in elevation between the pond 

 level and the level of the water on the bog when it is completely flooded. As 

 there are a number of plants listed as having only a 1-foot lift, it is likely that 

 this definition was not used in all cases. The lift varied from 1 foot to 24 feet, 

 with an average of 5.6. Table 5 shows that most of the plants had lifts of 

 from 3 to 6 feet and that few plants had lifts of more than 8 feet. 



The individual plants showed a wide range in power provided for bogs of 

 equal acreage and equal lift. A fairly close coordination is expected between 

 horsepower and "acres x lift," but there was great variation in this ratio for 

 individual plants. For example, on the 6-foot lift, a 1-acre bog was equipped 

 with a 30-horsepower motor, while an 80-acre bog was equipped with a 25- 

 horsepower motor. As an average, .288 horsepower was provided per "acre x 

 lift" for electric installations, .537 for gasoline installations, and .461 for all 

 installations. 



It is interesting to compare the actual installations with what may be con- 

 sidered theoretically required or desirable. Assuming that bogs are to be 

 flooded to an average depth of 12 inches in 4 hours and that the ditches are 

 full to the level of the bog at the beginning of the 4-hour period, a pumping 

 capacity of 1,360 gallons a minute is required per acre. Assuming a pump 

 efficiency of 70 percent, the power requirement is .489 horsepower per "acre x 

 lift." If the efficiency of the pump is 35 percent, the power required will, of 

 course, be .978 horsepower, which is about twice the average power provided 

 per "acre x lift" for the State as a whole. The pumping plants in Barnstable 

 County averaged slightly larger than this theoretical requirement, and those 

 in Plymouth County were much smaller. The survey does not show the 

 efficiency of the various pumps, but it is well known that many pumps have 

 low efficiencies and many engines do not develop their rated horsepower. The 

 average cranberry-bog pumping plant probably operates with 35 to 50 percent 

 efficiency. 



