Designing a crown block to safely hoist an 800-ton load does not 

 appear to be difficult. It is safe to conclude that an acceptable crown block 

 could be built; it would most likely be a larger version of present units. 



Traveling Blocks. It is desirable to have a unitized traveling block, 

 i.e., one where the hook is attached directly to the block. Such an 

 arrangement decreases the length of the hoisting equipment and thereby 

 increases the length of pipe which can be handled in one lift cycle. Unitized 

 traveling blocks have limited capacities, however, so the block will undoubtedly 

 have to be separate from the hook. Capacities of some of the larger block- 

 hook combinations are presented in Table B-4. 



Table B-4. Characteristics of Standard Traveling Blocks 



Manufacturer 



Capacity 

 (tons) 



Weight 

 (tons) 



Continental Emsco with Byron Jackson 

 "5,000" Dynaplex hook 



Gardner Denver with Byron Jackson 

 "5,000" Dynaplex hook 



McKissack with Byron Jackson 

 "5,500" Dynaplex hook 



National Supply 



Regan Forge with Byron Jackson 

 "5,500" Dynaplex hook 



600 



550 



500 



500 

 500 



7.8 



9.0 



8.0 



11.2 

 5.8- 11.0 



It can be seen that currently available traveling blocks do not have 

 large enough capacities for the purposes of this project. Again, however, it 

 appears logical to assume that a traveling block of the desired capacity could 

 be designed and built by simply increasing the size of the largest units 

 presently available. 



Draw Works and Winches. The draw works and hoisting drum are 

 typically rated on the basis of horsepower. A unit of 2,500 horsepower is 

 considered large, but for the MOHOLE project a unit of 4,000 horsepower 

 had been designed. A typical unit can hoist 500 tons at a rate of 0.6 feet per 

 second using a 6-sheave block. 



115 



