14 



UNITED STATES COAST GUARD 



If a force of 50 pounds is applied 

 at point "F" of a two fold tackle as 

 shown; 



(a) What weight may be lifted at 

 "W," allowing 10 percent friction loss 

 at each sheave? 



(b) If "W" is lifted 2 feet, how 

 far must the line at "F" be pulled? 



(c) What is the stress on the 

 padeye at "C" when lifting the weight? 



"C" 



What objection could be raised to a 

 number of men, such as troops, march- 

 ing in step up a gangway? 



How is the size of a shackle meas- 

 ured? 



What precautions would you take 

 with regard to a shackle used aloft on 

 a boom or the mast? 



When a seaman shackles his bos'ns 

 chair to rigging for work aloft such as 

 slushing down, what precaution must 

 be taken if a screw pin shackle is used? 



In handling a weight, what part of 

 a tackle has the greatest stress? 



(a) In hoisting. 



(b) In lowering. 



(c) State reasons for answers to 

 (a) and (b). 



What should be done when, in trans- 

 ferring bulk oil, an oil hose leaks badly 

 at the connection ? 



Describe the proper method of clos- 

 ing a valve in cargo piping, and state 

 the reasons for doing it in this manner. 



Describe the proper method of open- 

 ing a valve in cargo piping. 



What precautions should be taken 

 before starting a steam windlass or 

 winch which has been standing idle? 



Name seven of the ten parts of a 

 block indicated on the diagram below. 



Stevedores employed on vessels fitted 

 with two booms at a hatch occasionally 

 use a floating block between the two 

 booms for handling weights, swinging 

 the two booms together, as shown in the 

 sketch below. If the weight is 6 tons, 

 what is the weight on each boom? If the 

 shackle joining the two runners should 

 fetch up on the floating block, what will 

 be the effect? 



*■ Shackle 



