The pipe ducts were welded to steel anchor plates in the hull. The structure was cross braced 
ly fore and aft with 34-inch wire rope. 
d at the inside surface of the hull. Spaces transverse 
eae the plates and the hull surface were dry- A 3-inch steel pipe was used for the horizontal 
be RS & 5 Ear, strut at the base of the columns. 
pac ; 
The columns were joined to the saddles with 
epoxy compound. Steel plate rings, 4-inch 
Nepal eal with holes for attaching the platform 
deck, were bonded to the upper ends of the columns. 
The columns were prestressed to 290 psi resultant 
compression and tied to the hull cylinder with 
eight :-inch, Grade 270 strands located in the 
ducts. Strand ends were anchored with chucks on 
the end ring plate and plates on the inside of the 
hull wall (Figure 6). The ducts were pressures 
grouted with cement mortar. 
Figure 7. Welding of deck frame components. 
The hulls were closed off with steel bulkheads 
of 5/8-inch plate attached with cap screws to the 
hull end plate rings; a neoprene gasket was used 
in between for water tightness. Sixty-six (66)- 
inch concrete hemispheres were attached in turn to 
the bulkheads that were strengthened with eight 
radial stiffeners for this purpose. The hemispheres 
were seated on the stiffeners and secured by a l- 
inch diameter rod at the center. 
Figure 6. Interior view of hull showing 
h bl After assembly the structure was sandblasted 
column anchors and anchor blocks. and painted. For evaluation four different anti- 
fouling coatings were applied to different exterior 
portions of the concrete. Three coatings were 
Assembly to Launch rubber-base compounds (DEVCON, Phenoline 300 and 
rubber adhesive), each with 10 percent tributyl tin 
The fabricated units were truck delivered to 
oxide as the toxic agent to discourage growth. The 
NCEL in two sections, each conststing of the 32-ft fourth coating was a two-part urethane base impreg- 
hull with columns attached. Weight of each section 
nated with very fine specially-cut polyester fibers; 
was approximately 44,000 lbs. These were subse- this non-toxic coating derives its effectiveness for 
quently aligned and plumbed, ready to receive the anti-fouling by providing a non-attractive surface 
deck. to growth. A portion of the concrete was left 
= aennen hess on Powe 9 Gan uncoated for reference. The steel deck was coated 
e main dec eams, > o 
with a primer int. 
sisted of pairs of 8-inch channels spanning trans- P Fe 
versely column to column; the channels were welded 
x As a convenience to launching the structure 
to the top column plated ring. Open floor grating was assembled on the dock. Launching consisted of 
(14 x 1/8 bars @ I-3/16 inches on center) was used hoisting the model with a YD-193 floating crane and 
for the deck. setting it in the water as shown in Figure 8. The 
5 lift lines were attached to the top plate rings of 
Three steel ballast tanks were installed in the corner columns. The structure, according to 
each hull, fore, aft and amidship. Each tank had the crane load indicator, weighed 119,000 lbs. Of 
a nominal capacity of taking on 5,000 lbs of sea this, approximately 100,000 lbs was concrete. 
water ballast. Individual fill/suction lines were ? 
plumbed to each tank from a control point in the 
deck. Access to each hull through a corner column 
was provided by drilling/coring an 18-inch opening 
C-9 
