Anchor. After the surface platform is in position, the guideline 

 is established. The anchor can be lowered by free fall or by lowering 

 from one or more guidelines. The shape of the anchor directly affects 

 the hydrodynamic stability during a free-fall deployment. Motion com- 

 pensation or surface action decoupling are definitely required for 

 successful lowering with lines. 



Guidelines and Lift Lines. The guideline usually is attached to 

 the anchor during the deployment, but it can be attached to the anchor 

 after the deployment by using manned or unmanned submersibles. 



The guideline can also be established by a recall buoy attached 

 to the anchor. Upon a recall acoustic signal the buoy floats to the 

 surface with a messenger line. This line is then used to establish the 

 guideline. Quick-release connectors and submerged winches are needed 

 for such operations. 



It is also possible to establish a second guideline using an exist- 

 ing guideline. A release connector is needed for such an operation. 

 Since precise alignment is needed for such matings, a more sophisticated 

 bottom guidance system should be designed and tested before any attempt 

 is made on the remote establishment of a second guideline. 



Guide Frame and Payload. The main lift line and the guidelines 

 are supported from a surface platform. The guide frame and the payload 

 can be attached and released from the guidelines on deck or in the 

 water. An A-frame is required, together with other deck load-handling 

 equipment, if the payload is to be rigged to the guideline system on 

 deck (Figure 14). For in-water handling, divers are required. Since 

 the divers have limited communication with the surface and other dis- 

 advantages, on-deck rigging of the payload to the guideline system is 

 recommended whenever possible. 



Winches. Compensation for motion and decoupling of surface excita- 

 tions can be provided by constant-tension winches, air-operated winches 

 (Figure 15), and counterweight systems. The method selected depends on 

 anticipated sea state conditions. Since constant-tension winches of 

 large capacities are difficult to locate, pneumatic winches are considered 

 satisfactory. The use of such equipment should be limited to deep water 

 and moderate sea conditions. For mild sea states with smaller surface 

 motions, a counterweight system is satisfactory for reducing surface 

 excitations. The elongation of the nylon rope can provide limited motion 

 compensation, thereby allowing the operation of guidelines without other 

 compensation equipment in deep water. 



15 



