Further to my conversation with Jonathan at Deans Marine, a most helpful individual I might add, is a brief description of "What's in there" pertaining to the last picture posted above...
Image shows the boat, where the left hand side of the photo is looking forward towards the foredeck where the foredeck 6 pounder is mounted. what you can see in the picture, immediately in front of the batteries are the 2 fuse holders, one for each speed controller and their corresponding pair of motors - They are set with 25 amp mini blade auto type fuses, which seem to be quite adequate for the load from the motors.
The prop shafts are mounted with 40mm three blade props, giving a reasonable turn of speed for about 25 minutes of battery life. Even after that time running, the motors, while warm to the touch, are not so hot as to induce one to recoil away from touching.
Interestingly, when testing the motors in the pool, with an amprobe, and with 35mm props mounted, at low speed, the amperage draw was 5.8 amps for the port pair and 5.1 amps for the starboard pair, however, when turned up to flank speed the combined 4 motors barely topped 1.5 amps. My theory is that as the model was held stationary - in order to get an amperage reading, that as the speed of the prop rotation increased, the load on the shafts decreased, as the water was unable to fill the void created by the the back thrust of the props in motion. Anyway, this means that I don't really know what the actual running load is, whatever, it is obviously very comfortably under 25 amps, my next trick being to change the fuses to 20 amp max, which will probably be fine, and so give the speed controllers and motors a greater safety margin.
OK, Back to your question...what's in there. Just in front of all the wiring is the switching mechanism for the turret mount motors for the 2 6 pounder guns. It is a stand cannibalized from an old Meccano set, with a piece of 1mm styrene for the mounting board for the two servos, which are connected to 2 DPDT switches, actually the switches are centre off type. These in turn are connected to their corresponding actuator motors, which turn the reduction gears, rotating the turrets at a fairly reasonable slow rate. One partial set of reduction gears/drive linkage can be seen at the extreme top left corner of the picture. The actuator motors are from a Maerklin Metal set. Bulky, a little noisy in the workshop, but almost silent out on the water, but functional, and the best part, totally free, as all the parts have been laying about the house in boxes for years now.
The battery pack (of 4 AA type) to the right of the main 6v battery, is the power source for these 2 actuator motors, and are the only disposable batteries in the boat. Given the amount of use and amperage draw from these motors, the battery life expectancy is quite a few months, as obviously the boat isn't in the water all the time. The switch mounted above the batteries is dedicated to to those batteries and insures that there can be no chance of one of the DPDT switches being left in a closed circuit condition when the boat's electrics get shut down after use.
The shelf just visible on the port side (bottom edge) is for all the radio gear, which at the moment is just the receiver. It is high up, and out of the way, so any water shipped through the prop shafts, (which is not much), presents absolutely no danger to the radio.
The radio gear is a "Robbe" F-14 marine version, with the dual throttle sticks. I plan on installing a sound system with various noises...money permitting, in the future. With this in mind, I made a deck, between the prop shafts and the rudder assembly, where there is plenty of room to mount everything, as well as the drive mechanism for the aft 6 pounder. With engines roaring, guns blazing, machine guns chattering, and alarms screaming, it will be sure to terrorize the duck population on the lake where we run the boat, let alone what it might do to the local joggers .
