the sections together with longitudinal cables or rods. The maximum 
practical length for such an assemblage is subject for further study. 
Water ballast can be used in the columns for buoyancy control. When 
all legs are assembled, the interiors can be pumped dry. The same vari- 
ations discussed in the previous technique apply to this concept. 
In this technique the segments may be towed to the assembly site or 
shipped via barge. In either case, heavy-duty handling equipment will 
be involved; the need for hoisting heavy loads in the open sea is a dis- 
tinct disadvantage. 
Slip Form Technique. The use of a slip form (discussed earlier in 
the section on construction procedures) offers a different kind of 
assembly procedure. In this technique the floating deck has circular 
forms built or installed into the deck openings. A cement mixing plant 
can be installed on the deck, or equipment which can receive concrete 
from a nearby floating plant can be installed. As in other assembly 
techniques, the requirements for sufficient buoyancy and structural 
adequacy of the deck will require investigating. 
Semi-Submersible Platform 
As with the elevated platforms, the semi-submersible can be con- 
sidered to consist of two major sub-assemblies: (1) the superstructure 
or deck and (2) the supporting buoyant sub-structure. The deck of the 
semi-submersible differs little from that of the other types of platforms 
and can be constructed in the same way, most likely as modular units 
post-tensioned together to form the complete deck. Assembling the pon- 
toons and vertical supports are unique problems. 
If the cylindrical buoyancy pontoons are cast monolithically, no 
associated assembly problem exists. The alternate method of fabricating 
short sections with assembly by post-tensioning does require some thought. 
The most promising approach appears to be assembly on a polder, behind a 
dike. The sections could be positioned end-to-end and post-tensioned. 
Vertical support elements and necessary framing would be added and post- 
tensioned. After completion of the assembly, the basin would be flooded 
and the sub-structure floated out. Deck elements could be cast at an 
adjacent site and placed onto the sub-structure at sea. 
Barge Platforms 
Monolithically cast barge modules would be built and launched with- 
out need for assembly. The same would apply to a barge module composed 
of prefabricated elements. The latter would probably be connected to- 
gether by post-tensioning. As in ship construction, it may be desirable 
to fabricate the hull on land, launch it, and then outfit it while 
floating. Where draft is a problem, deck elements could be added at sea. 
