單項(xiàng)選擇題Neglecting friction，you desire to lift a 300 kgs weight with a stress on the hauling part of 100 kgs.Which of the following tackles would you use?（）.

A.Gun tackle
B.Luff tackle
C.Two-fold tackle
D.Double-luff tackle


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1.單項(xiàng)選擇題Manila slings should not be used to load（）.

A.cotton
B.lumber
C.steel
D.tires

2.單項(xiàng)選擇題Manila lines in which the strands are right-hand laid（）.

A.should be coiled in a clockwise direction
B.should be coiled in a counterclockwise direction
C.may be coiled either clockwise or counterclockwise
D.should never be coiled

3.單項(xiàng)選擇題Limit switches on gravity davits should be tested by（）.

A.the engineers，from a panel in the engine room
B.shutting off the current to the winch
C.pushing the switch lever arm while the winch is running
D.All of the above

4.單項(xiàng)選擇題In securing a towing cable，consideration must be given to letting go in an emergency. The possible whip of towlines when released can be overcome by（）.

A.increasing the shaft RPM prior to release
B.using a pelican hook for quick release
C.using preventers
D.using a short chain for the lead through the stern chock

5.單項(xiàng)選擇題In moderate wind and current what should be the length of chain with a single anchor?（）

A.5 times the depth of the water in good holding ground
B.10 times the depth of the water in shallow water
C.2 times the depth of the water in poor holding ground
D.8 times the depth of the water in deep water