/ 



/ 





barge by addiug temporary buoyancy topside to safely float the anchor 

 during its long tow to the OTEC site. Once at the site, th'.- buoyancy 

 compartments would be flooded to initiate the free-fall descent. 



The mooring line can be installed either by carrying it to the 

 seafloor on the anchor during emplacement or by lowering and attaching 

 the line to the anchor after emplacement. If the mooring line is car- 

 ried to the seafloor on the anchor, then the upper end would be released 

 from the anchor after seafloor contact and will be returned to the 

 surface by a syntactic foam-filled float. If the seafloor end of the 

 mooring line is attached after anchor emplant, the line lowering, position- 

 . ing, and attachment operation would probably be carried out by an appro- 

 priately equipped drillship. 



Tests with a 0.15-m (6-in.) diameter, scaled model of the free-fall 

 anchor showed that the anchor is stable during free-fall: the anchor 

 will quickly right itself to a horizontal attitude; it does not translate 

 nor rotate during free-fall; and pitching motions are not of serious 

 magnitude - about +0.1 rad (±6 deg). Terminal velocity of the prototype 

 is predicted to be 6 m/s (20 fps) or less. 



The structural integrity of the proposed free-fall anchor on land- 

 ing has not been verified, because the force history and pressure distri- 

 bution on the anchor during loading are not known. Development of this 

 force and pressure data will require a better understanding of the 

 interaction between the anchor, the water, and the soil on landing for 

 all possible anchor - seafloor o^rientations . Then structural analysis 

 and design of the anchor can proceed. Time and funding limitations have 

 precluded such an analysis. However, an approximate analysis did show '■ 

 that structural integrity of the free-fall deadweight, when landing, on 

 typical deep ocean soil seafloors, will probably not be critical. Even 

 if this preliminary finding should prove faulty, structural integrity 

 during landing can be maintained by decreasing the free-fall velocity of 

 the anchor system. The velocity can be decreased by decreasing the 

 submerged weight of the anchor during free-fall by temporarily adding 

 buoyancy or by increasing the drag on the anchor system by adding drogue 

 buoys . 



