290 WET SUITS 



Boot and mitt circuitry were handled as specific cases. The wire configurations differ 

 from those shown in Fig. 111. The mitt circuit design provides heat to the dorsal side of the 

 thumb and hand and to the ventral side of the fingers. The boot circuit provides heat to the en- 

 tire foot area. 



The need to interconnect the various suit parts required the use of safe underwater elec- 

 trical connectors. Aside from watertight integrity, the requirements of the connectors are to 

 take the current to have low contact resistance, and to be as small as possible. The current 

 requirements are 3.5 amperes for the mitts and boots connectors and 15 amperes for the jacket 

 and trouser connections. The mitt and boot circuits were designed to be supplied independently 

 of the remainder of the suit. Electro-Oceanics connectors were employed, principally because 

 of their small size and flatness. The connectors were fastened to the suit parts through neo- 

 prene oral inflation tube fittings. 



Feeder wires to supply the resistance wires were chosen to be B&S gage 22 or 24 copper, 

 depending on the length of the feed wire. It is important that the resistivity of the feed wire be 

 very small compared to the resistivity of the heater wires, to prevent large voltage drops 

 across the heating circuit. Such voltage drops result in uneven heat release. 



Battery Pack and Power Control 



The battery-pack design includes eight silver-zinc cells in fabric pouches, interconnecting 

 cell cables, a battery cable assembly attached to a power-control box, and a 2-in. nylon belt 

 with a fixed buckle, rather than a quick- release type. 



The silver-zinc cells are Yardney LR 85 cells modified for this application. The 12-volt 

 supply consists of two banks of cells, four cells per bank, in series. The cell banks are paral- 

 lel switched to provide one-quarter heat power to the suit. The cells were designed so that 

 they could be immersed without using an external pressure housing. They are inserted into 

 fabric pouches made of heavy-gear diver's dress material. 



The modification of the LR 85' s consists of use of watertight electrical connectors and 

 total filling with electrolyte. Electro-Oceanics 51E1F female connectors were attached to the 

 cell terminals and potted in place with an epoxy compound. Figure 112 shows one of the cells. 

 Compressibility of the cell is minimized by nearly total fillings of the cell with the potassium 

 hydroxide electrolyte. Volume changes due to gases remaining in the cell after filling, and 

 gases generated by the cell during discharge, are compensated for through use of a deformable 

 rubber finger. Figure 113 shows the pressure-compensating mechanism. 



The interconnecting cell cables consist of two Electro-Oceanics 51E1M male connectors 

 molded onto 11 in. of B&S gage 16 wire. A battery-cable assembly, specially designed and con- 

 structed for the purpose, is electrically connected to the ends of both cell banks. The cable 

 terminates in an Electro-Oceanics 4104 feed-through fitting mounted on a power control box. 



The electrical circuit for the battery-pack control box is shown schematically in Fig. 114. 

 The switching arrangement provides five options; no power, full power to all parts of the suit, 

 one-quarter power to all parts of the suit, full power to the hands and feet only, and one-quarter 

 power to the hands and feet only. It was felt that such options would be required to cover the 

 range of body-heat production during various levels of work. 



The list of components shown in Fig. 114 is given below. 



Bj-Bg Yardney LR-85 modified silver-zinc cells 



C,-C,, Electro-Oceanics 51E1F female connectors 



1 Id 



Cj7 -C32 Electro-Oceanics 51E1M male connectors 

 C33 Electro-Oceanics 4104 feed-through fitting 



