SPECIMEN EXAMINATION FOR SECOND MATE 



49. 



If a force of 50 pounds is applied at 

 point "F" of the luff tackle shown: 



(a) What is the weight that may 

 be lifted at "W," allowing 10 percent 

 friction loss at each sheave? 



(b) If "W" is lifted one foot, how 

 far must the line at "F" be pulled? 



(c) What stress is put on the pad- 

 eye at point "C" when lifting "W"? 



A manufacturer states that the 

 breaking strength of his 3-inch circum- 

 ference manila rope is 9,000 pounds. If 

 you use this rope as a single whip cargo 

 fall, what is the safe working load, 

 using a factor of safety of 7? 



On merchant vessels when using 

 booms to handle heavy weights or deli- 

 cate objects, how do you reduce d3mamic 

 stresses; that is, stresses due to change 

 of velocity of the load, such as taking 

 up fast on a load at rest, increasing 

 speed of hoisting, or suddenly stopping? 



Why is the hauling part of a heavy 

 lift purchase usually led to the mast 

 rather than directly to the winch? 



When is the tension of a topping lift 

 at a maximum ; i.e. at what angles with 

 the mast is the heaviest stress put on 

 the topping lift due to the weight of the 

 boom and any weight being lifted? 



25. CARGO STOWAGE AND HANDLING. 



In discharging cargo into a lighter as 

 shown, with only a small amount of 

 drift on the boom, what care is neces- 

 sary? 



If 2,000 tons of iron ore with a stow- 

 age factor of 15 is stowed in a cargo 

 hold of rectangular shape whose bottom 

 is 50 feet long and 45 feet wide, what is 

 the height of the center of gravity of 

 the ore above the bottom of the hold? 



What type of tools should be used for 

 opening and closing oil tank hatch 

 covers? 



At what pressure should the oil dis- 

 charge piping of tank vessels be tested? 



You are required to load wet logs in 

 No. 4 lower hold and cases of canned 

 goods in No. 4 'tween decks. What pre- 

 caution would you exercise to avoid 

 sweat damage to the canned goods? 



Desci-ibe the stowage of cement and 

 the precautions necessary for protec- 

 tion of other cargo in the same hold 

 with cement. 



Define : 



(a) Explosive range. 



(b) Fire point. 



(c) Flash point. 



Describe briefly how the amount of 

 water below the oil in an oil tank may 

 be determined. 



Define : 



(a) Inflammable liquid. 



(b) Combustible liquid. 



What precautions must be observed 

 in the choice of wood for use as dun- 

 nage? 



Describe the methods employed in the 

 shipment of wet hides and the precau- 

 tions necessary for good cargo turnout. 



Describe the precautions necessary in 

 the stowage of essential oils. 



Note: "Essential Oils" is a term used to de- 

 scribe such oils as almond, attar of roses, clove, 

 wintergreen, lavender, etc., which are used in 

 perfumery and cooking. 



