range of ship periods 



n r 



U^ 



Hj 



maximum allowable force/X ratio 

 10% of line tension 



1 ,000 feet 



Period (sec) 



Figure 12. Force-to-amplitude ratio for 6,000-foot length of nylon rope with 

 40,000-pound load, 5% accumulator size. 



diesel, rated at 250 bhp at 2,100 rpm, which drives 

 both a main hydraulic pump that powers the traction 

 winch and auxiliary pumps that drive the other 

 system components. The engine is fitted with a 

 Jacobs compression brake which, when activated, 

 converts the engine into a compressor capable of 

 absorbing almost as much power as the normal out- 

 put rating. When the unit operates in this mode, 

 auxiliary hydraulic pumps continue to be driven and 

 all system functions remain operable. 



Turntable Unit 



The motion-compensating, traction, and power 

 components are all mounted on a turntable capable 



of 360-degree rotation controlled by the operator to 

 allow offloading or onloading from the support-vessel 

 deck. The turntable also permits the placing of the 

 boom tip at the most advantageous position with 

 respect to the ship for a lifting or lowering operation. 



Line-Storage Unit 



The line-storage unit is shown to the right in 

 Figure 13 and in detail in Figure 15. It is capable of 

 storing 7,000 feet of 3-inch-diameter nylon line 

 (volume limit) or 7,000 feet of 1-1/2-inch-diameter 

 wire rope (weight limit). Line tension during haul-in 

 or payout is selected by the operator and auto- 

 matically controlled to a level between and 2,000 



11 



