THE CENTRAL TUBE OF THE FLOAT AND TRIM OF THE SPHERE 



There is a vertical steel tube 47-3 in. in diameter, with a wall thick- 

 ness of 0-394 in. in the centre of the float, which goes right through it. 

 It is welded to the two extremities of the hull. It has three separate 

 functions : 



The interior of this tube serves as a reservoir for the stabilizing 

 petrol. At the top of the tube a big hook is aflixed which allows the 

 crane to lift the entire bathyscaphe: thus the load is well distributed 

 over the top and the bottom of the hull. The bottom of the tube 

 projects slightly below the float : the cabin is suspended from it. The 

 cabin is carried by two bands of mild steel 3-94 in. wide and 0-394 in. 

 thick which run round it and cross each other at its base and of which 

 the four extremities are connected by means of four straining-screws 

 at four points of the central tube. Between these steel bands and the 

 cabin there is a thick layer of rubber, as well as between the cabin 

 and the base of the central tube. By means of the straining-screws the 

 cabin is held tightly against the tube. 



At the base of the cabin an iron cross prevents the steel bands 

 from getting out of place and assures them a certain protection. 



According to calculations the safety-factor of this suspension is 

 very great. Even so we tested it and this was done in the following 

 manner : 



While the float was at the dock and rested on its cradle, we alter- 

 nately loosened one and then the other of the steel bands. The load 

 on each band was thus doubled in turn. But as the cabin is roughly 

 twice as heavy in the air as in the water, the suspension was thus 

 tested with a load four times the normal. 



As a precaution we also surrounded the cabin with four large cables 

 which would suffice by themselves to carry it. 



If this construction is compared with that adopted for the FNRS j, 

 it will be seen that our old cabin of the FNRS 2 is resting now in a 

 veritable basket of steel framework : the factor of safety of this sus- 

 pension seems very much greater than for ours. However, I should 

 not like to make an exchange of the two systems of fixing. I consider 

 that a measure of safety corresponding generously with technical 

 norms is enough: moreover, it is obvious that the basket of the 

 FNRS 3 runs the risk of becoming caught in submarine obstacles. 



[8z] 



