i: The Float 



TH E float of the Trieste was built at one of the dockyards belonging 

 to the Canderi Riuniti delV Adriatico Company of Trieste at Mon- 

 falcone, a pretty little industrial town lying between the Karst hills 

 and the sea. 



As is often the case in technical problems, different requirements 

 suggested mutually incompatible solutions, and the answer was some- 

 times a compromise based more on judgment than on mathematical 

 formulae. We were lucky to be able to profit by the long experience 

 of M. Loser, the engineer at the dockyard. I have special gratitude for 

 him : he spared neither time nor trouble in seeking with me the best 

 solutions of a great number of problems set by the construction of 

 our ship, which varied, it must be said, in a marked way from estab- 

 lished practice in conventional naval architecture. 



Fig. 7 shows the structure in its main lines: the float, in plates of 

 mild steel, fusiform or more correctly cylindrical, tapering equally at 

 both ends. Total length 49 ft. 6 in. ; diameter of the cylinder 1 1 ft. 6 in. 

 (3 • 5 m). Inside there are twelve compartments for petrol of a total volume 

 of 3736 cu. ft. : at each end an air tank of 212 cu. ft. The central com- 

 partment of a capacity of 153 cu. ft. contains stabilizing petrol. It 

 is built in the form of a vertical cylinder. Each of the other com- 

 partments and the two tanks which occupy the entire width of the 

 float are separated from each other by twelve transverse partitions, or 

 bulkheads, of corrugated iron. The thickness of the metal sheets 

 forming the bulkheads and the air tanks is o-i 18 in. (3 mm.) ; that of the 

 metal sheets on the outside of the compartments for petrol is 0-1973 in. 

 (5 mm.). The weight of the float when empty is 15 tons: this float enjoys 

 the luxury of having its bilge-keels inside : immersed in the petrol, they 

 damp out rolling movements considerably by their friction with the 

 liquid. 



The reader will see from Plate XI the dark lines painted on the hull 

 of the Trieste : their purpose is not to imitate a zebra but to indicate 

 clearly the position of the partitions, for, during the operations on 

 land, it is important to support the bathyscaphe where the float is 

 stronger, that is to say, at the bulkheads. Moreover it is important 

 that, in case of damage, it can be immediately ascertained which com- 



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