. Development and evaluation of a motion compensating lift system for deep ocean construction. Underwater construction; Marine engineering; Civil engineering. Figure 13. Motion-compensating lift system. Motion-compensating/traction unit (left); cable-storage reel (right). pounds; normal setting for wire rope is about 500 pounds. The level-wind mechanism is adjustable for all line diameters between 1/2 and 3 inches. Provision was made for the addition of electrical slip rings to allow the future use of electromechanical cables. Control System Operation of the MCLS is controlled from a single po
. Development and evaluation of a motion compensating lift system for deep ocean construction. Underwater construction; Marine engineering; Civil engineering. Figure 13. Motion-compensating lift system. Motion-compensating/traction unit (left); cable-storage reel (right). pounds; normal setting for wire rope is about 500 pounds. The level-wind mechanism is adjustable for all line diameters between 1/2 and 3 inches. Provision was made for the addition of electrical slip rings to allow the future use of electromechanical cables. Control System Operation of the MCLS is controlled from a single point by one operator. The controls and instru- ments, shown in Figure 19, are grouped in functional clusters for ease of operation. The control console itself is constructed in an L-shape with the top sloping down toward the operator. A typical operation begins with the system in the hard mode and the engine running. After com- pletion of a preoperation checklist the operator raises the payload off the deck high enough to clear the ship's rail. Then he activates the turntable control to rotate the payload out over the stern into launch position. When the launch position is reached he begins to payout cable and, as soon as the payload is in the water, he shifts into soft mode and activates the automatic boom-centering circuit (spring pressure was set previously to just balance the load). Rate of descent is then controlled by the winch control lever and, with the system operating as designed, this is the only control the operator needs to touch during the remainder of the lowering or lifting operation. Recovery is accomplished by reversing the launch procedure. TEST PROGRAM Shop Tests Formal testing of the MCLS began at the con- tractor's facility with a static load test soon after fabrication of the hardware. Strain gages were placed at all critical areas, and a series of loads was applied to the boom tip. Analysis of the strain-gage information showed one location near the turnt
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