will in all likelihood determine the "best'' assembly method. Thus, if 
the choice is "to proceed"’ with elevated platforms, several at-sea 
assembly options should be investigated. 
Semi-Submersible Platforms 
The most attractive construction method appears to be one where 
the buoyant elements are assembled in the dry into a complete module 
and launched; the deck elements are added subsequently at sea; sizing 
in plan would be optimized during design. The buoyant cylindrical 
columns and hulls would consist of post-tensioned, precast, prestressed 
elements, although monolithic construction cannot be eliminated at this 
time as an option. The columns, hulls and necessary framing would be 
fabricated and assembled into a complete buoyant module. Construction 
would probably be best suited to a polder and dike. The draft would 
be held to a minimum by installing the deck after launch. The deck 
construction could be similar to that for the elevated platform, dif- 
fering only in the final assembly aspects. Where a deeper draft could 
be tolerated, portions of the deck would be added before launch. 
Barge Platforms 
The construction sequence of this type platform is seen as some- 
what similar to that for the semi-submersible, i. e., launching the 
completed buoyant module and adding the deck at sea. Monolithic 
construction of the hulls appears to be the choice, but as with the 
semi-submersible, alternatives require investigating. Portions of the 
deck could be monolithically cast (or assembled) with the hull before 
launching within draft limitations. The polder and dike appear to be 
a likely construction site. 
METHODOLOGY FOR COMPARING CANDIDATE PLATFORMS 
To avoid a premature selection of the concept (configuration, size, 
materials, construction techniques, etc.) a methodical, systematic 
approach is suggested. Such an approach has mechanisms available to 
further the concept formulation and establish the performance baseline. 
A number of attractive options for sub-systems should be explored and 
decision points reach before proceedings with the system definition. 
Accordingly, no attempt is made to rank the viable alternatives at this 
time. 
Particularly lacking, and absolutely essential for a rational choice 
of alternatives, is a well-defined statement of mission objectives and 
operational requirements. This is a common situation in the early 
definition and development of a major R&D program. A certain amount of 
flexibility is desirable prior to commitment of large amounts of re- 
sources. Eventually, however, a mission commitment will be made. From 
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