CONNING TOWER DOOR 



The conning tower door was installed on the forward 

 side of the tower to protect the interior from direct wave 

 impingement. In the past, this area was open and, during 

 towing, the seas which broke over the bathyscaph rolled 

 into the conning tower, causing damage. 



5. REPLACEMENT OF THE EXTERNAL 

 ELECTRICAL SYSTEM 



The entire electrical system of TRIESTE was replaced 

 during the reconstruction. Though part of the system had 

 been replaced in early 1959, the material delivered by the 

 contractor was not of good quality and caused severe prob- 

 lems. The primary control systems for lighting, motors, 

 and ballast still used the original wiring installed in 

 TRIESTE in early 1953 when the craft was built in Italy. 

 It was considered prudent to replace all this wiring, as it 

 was beginning to fail due to aging. In addition to replacing 

 substandard and aging wire, the wiring system was im- 

 proved by protecting all wire runs with plastic tubing and 

 pipe. 



Several changes were made in the design of the elec- 

 trical system in consideration of the new power system 

 and the many new equipments that were to be put aboard 

 TRIESTE. The new power system basically is a 2 4 -volt 

 dc system supplied by four external battery boxes. It 

 reduces the possibility of an electrical failure associated 

 with high voltages and high pressure. Thus, it was found, 

 with the previously used 500-volt lighting circuits and the 

 2 50-volt motor circuits, that the smallest pinhole in the 

 insulation of the wire would cause immediate failure of 

 that wiring circuit. Of course, the high current require- 

 ments of the motors and lights now dictate the use of an 

 external relay control box, as the hull connectors can 

 only carry a maximum of 10 amperes. 



6. PROPULSION MOTORS 



TRIESTE had two horizontal pressure- compensated 

 propulsion motors, each of which developed less than 2 hp. 

 In the three years preceding the reconstruction they had 

 given intermittent service and had become a continuous 



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