Ohio Class, Ballistic Missile Nuclear Powered Submarine, USS Kentucky SSBN737




The electronics, on / off, charge plug & battery configuration:

On / off:

Finding a watertight switch that was not too big, nor heavy, proved difficult. I therefore choose a reed relay. It's a relay that's activated with a loose magnet, like a "key" without which the sub can not be turned on..
The on / off button should be placed so that it is not visible from the outside. There are many ways to do this, and I’ll give you a few ideas:

A) One solution is to place the on / off button behind a rubber membrane within the electronics box, and then toggle the switch with one of the periscopes. One push = on, another push = off. 
This method poses a risk of foreign objects to accidentally shutting the sub off during operation.

B) Another solution is to toggle the switch through one of the tiny holes in the top bar or in the main hull (vent holes) using a piece of steel thread. 
This eliminates the risk of foreign objects accidentally shutting the sub off during operation. 

C) A third solution is to place the switch face down in the very bottom of the sub, and then make one of the holes a bit bigger allowing a finger to press the rubber membrane on the box in which the switch are located. 
This method poses a risk of foreign objects to accidentally shutting the sub off during operation.

D) A forth method is to place the on / off switch within the hatch that hides the recharge access if fitted. (See “Add-on’s, things you might / might not include” option A for details.)
This eliminates the risk of foreign objects accidentally shutting the sub off during operation, is even pretty neat, and offers a tool free operation.

I choose option "D", placing my "On/Off", "Dive enable/disable" and the recharge access under a hatch at the rear part of the missile deck. The missile tubes proved to small, and I wanted all under one hatch.  The results can be seen below.

Battery configuration:

A perfect battery for this is type no. "HHR450A-1" from Panasonic. Datasheet is available by clicking here.
The selected battery type is NiMH as this type has the lowest “memory effect”, and a high capacity. The rating for each cell is 1,2 V, and 4˝ Ah. I use 20 of these, wired 10 in series, in parallel with another 10 in series, to raise the available amperes. The system rating is thereby 12 V, and app. 9 Ah. 

The three-poled plug is the plug in the missile silo as described in the "Voltage Monitor" chapter. A gold plated jack, XLR or similar is perfect. The top most relay makes sure that the contact poles are not energized during dives etc, as this would otherwise cause corrosion. The relay is easiest put closest to the batteries, as there's no further external components. 

The bottom most regular relay (not the reed relay) controls the main power to the entire sub, and is controlled by the main on / off reed relay switch.

This configuration of the relays enables the sub to be sitting at the dock, charging the batteries, with the navigational lights on, and the fail safe's on-line. However, do not attempt to energize the engine, the charger is not able to carry such loads. It's also possible to turn the sub off during charging, the choice is yours.

Remember to use thick wires for both stability and to reduce voltage drop, to place the batteries low inside the hull, and to enclose the batteries in some watertight plastic coating (Like heat shrinking isolation material.), or within one of the WTC's.

The making:

The batteries were connected as shown above, and put in WTC1. Click here to see the results.
Here you can see how the on/off switch, dive disable/enable switch, and recharge plug was made.


Finding a watertight switch that was not too big, nor heavy, proved difficult. I therefore choose a reed relay. It's a relay that's activated with a loose magnet, like a "key" without which the sub can not be turned on..
 
   This module goes under the hatch in the missile deck.

The left reed-relay is the "On / Off", the right reed-relay is the "Dive disable / enable" switch. The two loose magnets are the activation "keys" for these switches. (Which drives relays within WTC1)

The round stereo jack socket in the middle, is for the charge plug for the batteries.

   The four holes are for cable ties.

The black fork-shaped piece holds the magnet "key" in place when fitted, and missing is only some sort of snap lock, securing the "key" when inserted. Here one of the "keys" has been inserted for illustration.

   This is the lower side, showing the two blocks that holds the reed-relays in place. A slot was filed in the aluminum, allowing a secure fit of the reed-relays. (They are shaped just as the magnet "keys", but has got wires coming out of them.

The gold plated stereo jack (recharge plug), and the reed-relay wires,  will be fitted with the wires from WTC1 shortly. 

  This shows where the control panel goes under the hatch. (not shown, hinge is not done.)
When the sub is surfaced, this will be above the waterline, thus allowing charging while in the water.

   This image shows the control panel temporary fitted within the hull, and with the hatch placed on top of the missile deck. Of cause the hinge will go under the missile deck, but this shows pretty well the general idea.  The little white block that sticks out from the left side of the hole, holds a small magnet. Another magnet is molded into the hatch, thus the hatch is pretty well "shut and locked" when closed. (If I turned the magnets the right way around, that is...) The brass arms was bend in one piece after sticking it through the hinge base. (White block) The ends of this brass rod ends in the two red blocks mounted on the lower side of the open hatch. The arc of the brass rods follows the circle that the moving hinge draws when operated, thus making them appear static.

Here's the finished result! :-) On / off to the left, charge input in the middle, and dive enable / disable to the right.
All hidden under the magnet locked hatch.





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