Alignment tolerance +0.1— 0.5 ft 



(translation) 



Alignment tolerance + 1 —3 deg 



(rotation) 



Attitude tolerance + 1 —3 deg 



(vertical) 



To the above could be added the following desirable system characteristics: 



1. Compatibility with interfacing subsystems, i.e., lifting/lowering 

 and near bottom transport. 



2. Reliability and safety. 



3. Greatest possible operating radius. 



4. Lowest possible cost consistent with meeting all of the afore- 

 mentioned criteria. 



DIVERCON I - A TEST CASE 



Before opening arguments for feasible deep ocean load positioning 

 and guidance systems, a shallow water, diver-assisted construction project — 

 DIVERCON / - will be described.'' ^ DIVERCON I, a diver construction 

 experiment developed for SeaLab III, serves as a microcosm for future 

 operations involving the positioning and assembly of very large construction 

 elements. The basic DIVERCON structure consists of a cylinder, open-ended 

 at the bottom and capped with a dome and is assembled from three mild-steel, 

 ring-shaped modules. The structure may be blown dry with air or a helium/ 

 oxygen gas mixture and used as a dry storage or diver repair facility. 



Hallanger reports that the three major technical problems encountered 

 during the development of DIVERCON were: 



1 . Devising a means for lifting and moving the modular elements 

 into a precisely determined location on the sea floor. 



2. Mating the modular units and obtaining an effective seal 

 between sections. 



49 



