with partial live load, and (2) partial sections with 80% of the deck 
removed. For the latter, only the buoyant sub-structure, completely 
assembled with necessary framing and partial deck, would be towed; the 
deck elements would be shipped separately for final assembly on station. 
While dynamic loads on the structure underway must be investigated, it 
appears unlikely that these will be a major problem since the structures 
will necessarily be designed to withstand the continuous dynamic loading 
encountered in the operational mode. This in itself will likely satisfy 
surface transport requirements. 
When speed is not a factor, the size of sections that can be trans- 
ported via towing is virtually unlimited. Perhaps the only constraint 
of any consequence is the limited water depths which are encountered 
in ports, canals, and channels throughout the world. If it is antici- 
pated the structures will be transported through any of these depth- 
limited areas, a maximum draft of 35 feet is the most that can be tol- 
erated. Although some shallow ports and facilities are being deepened 
and enlarged to accommodate large supertankers, it appears necessary to 
tow units smaller than sections, with a minimum draft, if they are to 
be towed through these areas. 
Towing Speed. It appears unnecessary and undesirable to limit 
the discussion of towing to any one speed. The possible missions for 
a MOBS platform could encompass a wide range of requirements from fast 
deployment, maybe on the order of an aircraft carrier, to something 
less rapid, where the time between the decision to deploy and the instal- 
lation of a complete base could be as much as a year. 
Whether the platform is self-propelled or towed, the most important 
characteristic with respect to propulsion requirements in the hydro- 
dynamic drag. Unfortunately, estimates of the hydrodynamic drag acting 
on the relatively complex hull forms are problematical at best. In the 
calculations which follow, wave drag acting on the buoyant elements of 
the elevated and semi-submersible platforms and the barge hull will be 
disregarded. This drag component, for barge hulls at least, is negligible 
for Froude numbers less than about 0.2. A basic expression for cal- 
culating drag is 
2 
D= %5PV CoA 
where p is the mass density of the fluid medium, V is the relative 
velocity between the submerged object and the fluid, C, is the drag 
coefficient, and A is the projected area of the object normal to the 
direction of relative motion. The principle difficulty in applying 
the eee is selection of the appropriate value for the drag co- 
efficient, For simple geometric shapes, e. g., spheres and circular 
Scilaniodg, ae drag coefficients are well defined, at least for Reynolds 
numbers less than 10 
*The section on towing speed was contributed by D. A. Davis 
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