However, for the 4,500-foot depth the amount of elongation of the steel 

 wire rope was large enough to maintain a taut guideline even though the 

 surface fluctuation was about 4 feet. Therefore, motion compensation is 

 not as critical for nylon ropes as it is for wire ropes nor for deep 

 depths as it is for shallow depths. The high dynamic tension that can 

 occur during the deployment of the guideline anchor block could dictate 

 the use of the motion-compensating winch as the lifting equipment. After 

 deployment the upper end of the guideline can be hard-stopped at the 

 deck. 



Guideline Hardware 



All of the guideline hardware functioned as designed except for 

 the mechanical release. A spring fell off in each of the anchor-mating 

 sea tests. This was one of the main causes for the line entanglement 

 during the mating tests. Stronger springs and better terminations are 

 the logical improvements. A method for preventing the rotation of the 

 payload during vertical movements should be sought. 



Anchor -Mating Experiment 



Although the mating operation was successful during the dry land 

 trials, both sea tests (Figure 13) were unsuccessful. In addition to 

 the malfunctioning of the mechanical release, the rotational behavior 

 of the payload in the water column under the hydrodynamic drag may have 

 contributed to entanglement, leading to the failures. Any asymmetry of 

 the payload about a vertical axis can cause the payload to rotate about 

 its vertical axis in vertical motion. Since the lift point of the pay- 

 load is practically touching the guideline, the lift line tension would 

 not yield any righting moment to counteract the rotation induced by the 

 flow drag. It is still considered feasible to complete a remote seafloor 

 mating using an improved mechanical release and a much slower lowering 

 speed. The effectiveness of the bottom guidance device, such as the 

 guide post, was inconclusive due to the failure of the mating exercises. 

 Underwater observance, such as with an underwater television, is highly 

 recommended for future mating tests. 



FINDINGS 



1. Only one line entanglement was observed during thirteen sea tests, 

 excluding the anchor-mating tests. That entanglement was probably caused 

 by undetectable slack at the lower end of the guideline. Most of the 

 static rotations of the guide frame were smaller than 180 degrees. Both 

 double and single guideline systems are considered safe to operate to 

 depths of 4,500 feet. Entanglement -free operation was made possible by 

 the use of nonrotational ropes and air-operated winches for surface 

 motion compensation. 



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