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    For the past five battling seasons I have had to maintain two battle ready ships at all times. This includes having both ships ready for all battles! One is for my son and the other for me. Soon I will have to maintain three ships!! I have developed a philosophy for reliable wiring that has worked well. I seldom have any problems.

    The first rule is to have good connections both permanent and removable.

    When splicing two wires together be sure to insulate the exposed joint. Use either shrink wrap tubing or brush on liquid insulation. The shrink tubing is slid over the joint and heated until it shrinks tight on the wires. A match flame is the minimum heat required. Be sure to heat evenly on all sides. The tubing works well but is somewhat of a pain to properly shrink. The liquid insulation looks like thick black rubber cement. You brush on one or more coats allowing several hours between coats. The liquid has the advantage that it will cover very irregular joints and is easy to apply. It is available at electrical supply houses and some autopart stores. Do not use electrical tape except for temporary repairs. After a year or so it starts to come off and it leaves a sticky mess on the connection.

    I attach all major electrical assemblies (motors, batteries, switches, etc.) with good quality connectors. I use the Tamiya type connectors commonly used on radio control cars (Figure 1). Some people have reported corrosion problems with these, but I've never had a problem.  These are available from mail order catalogs and many hobby shops. They and similar types are sturdy and have a positive, but easily manipulated, locking tab. I use these to connect my batteries, motors, and gun solenoids. To connect main power switches I use the spade type crimp-on automobile contacts sold at parts' stores. I buy switches with the spade terminals (I solder the spade lugs to the wire as well as crimping them). Screw terminals always seem to come loose. Do not use the audio type plug in connectors, which have a frequent tendency to short or fall out. This may seem like a lot of connections for a reliable system, but by using good connectors I have had no problems and some of the connectors are five years old!

Figure 1

    The reason I use so many connections is because of the second rule. Be able to replace, or remove for repair as needed as quickly as possible!! In line with this I can not disagree more with the popular recommendation to string your wiring through the ribs to get it out of the way. This makes repairs difficult both in the field and back home, as access is restricted, especially if everything is soldered together with no connectors. This placement also exposes the wires to the line of fire from BBs and damage from rams. The wiring is exposed to damage during patching and reskinning too. All the wiring should be inside the hull and armor, and be totally removable! This allows you to strip the ship for regular refurbishing and to closely inspect the wire's condition. The closest I come to permanently installing wiring is the grounding wire to the propshaft (explained later) and tying some wiring in place with string (which can be easily cut if needed). This idea of being able to remove the wiring applies to the water-tight boxes as well. With both my ships the boxes and main wiring harness come out as a unit and completely away from the hull. I never have to worry about dangling equipment when I strip the hull.

    When using connectors be consistent. The connectors come in matching pairs. One side plugs into the other. One side will have the contacts more fully covered than the other. Use this side for the power supplying end (batteries and the leads from the radio box to the motors). Use the other more open end for the power receiving end (power to the radio box and on the motor end). Think of the power connections for your outlets at home: sockets in the wall and pronged plugs on the equipment. The advantage of this is two fold, safety (the power leads are harder to short) and convenience (you can plug the batteries directly into the motors for testing).

    The third rule is: Use the proper size wire!!!!!!! I shudder when I see someone trying to run the prop motors with 24 gauge wire. The small wire presents a danger from overheating, and physical fragility. The small wire also causes significant voltage loss that affects the top performance of the drive and pump motors. Use at lease 18 gauge wire for the heavy current equipment and make the wire runs as short as is practical. For main power (battery) leads use 14 or 16 gauge wire.

    The fourth rule is that radios, and their connections are designed to stay dry! I learned this the hard way with my first ship. While all my servos and the radio were in watertight boxes the wire between the main box and the rudder servo box had an exposed connection. During my first Nats I would frequently have severe radio interference problems when this got wet and caused loading and signal feedback in the receiver. I now keep all the radio connections inside the boxes. This means that the rudder box is permanently attached to the main box, but this causes only a minor inconvenience during removal. In line with this I use watertight boxes exclusively. Several people have had good luck with the watertight servo modifications, but I prefer not to have them get wet in the first place. If you decide to use the watertight servos, be sure that the wiring connection is sealed.

    As long as we are mentioning the sealing of connections I would like to point out something that is not well known. The standard RTV Silicon Rubber we all know and love cures with an acid reaction, hence the vinegar smell. This acid will attack an electrical connection! In the short term you won't notice this, but it can hurt you later, especially if you sealed some delicate equipment. The hardware stores sell noncorrosive RTV (it is labeled as such) so spend a little more and buy that type.

    The fifth rule involves radio interference. First and foremost, be sure that your radio is in good shape and that the batteries are charged!

    Component placement is important. Try to keep the main power lines as far from the radio receiver as possible. I mount the radio at one end of the box and place the prop motor and pump motor servos at the other end, with the gun servos (and rudder servo if a separate box is not used) between. The antenna should also be as far as possible from the main power lines. It is desirable to place the batteries between the radio box and the motors if possible, but do not worry if this can not be done. If you use a separate rudder box, keep the box at least a couple of inches from the motors, and run the wiring away from the motors and their wiring. A good method is to run the power wires down one side and any signal/servo wires down the other.

    To cut down on radio frequency noise from the motors I shield the wiring to the motors and the rudder box. Shielding involves using wiring with a woven wire mesh covering. The mesh is connected to the negative (ground) wire. The mesh absorbs any high frequency noise in the wires, preventing the noise from radiating into the area. The type of wire I use is called Twisted Shielded Pair. This is a type not a brand. The fact that the wires are twisted adds to noise reduction (take my word for it, unless you want a "This exercise is left up to the student" type lecture). I use this type of wire from the main box to the motors (18 gauge) and to the rudder box (20 or 22 gauge). The smaller gauge is available from Radio Shack. The larger gauge can be obtained from one of the larger mail-order electronics stores or possibly from a local (non Radio Shack) electronics store.

    The wire consists of two insulated wires (twisted together) covered with the woven mesh and then with another insulated layer. To expose the wire for soldering cut the outermost insulation lengthwise and then around the circumference to free the piece, be careful not to cut the mesh. Peel the outer insulation away, using a pick carefully unravel the exposed mesh, and twist the strands together. Now just strip the inner pair of wires as you would a regular wire. When you are done the inner wires should be as short as possible so the mesh covers as fully as possible.

    For the motors, solder the inner wires to the power source and the motor, solder the mesh (on the main box end only, not both ends) to the negative battery wire. Do not solder the mesh to one of the motor leads as either one could be negative or positive depending on the direction the ship is steaming. The pump leads can also be soldered this way to simplify the soldering, even though the motor only runs in one direction.

    For the rudder servo wiring, solder the negative power lead (from the receiver) to one end of the mesh and the other end to the negative lead of the connector for the servo at the rudder box end, solder the positive power leads to one of the inner wires, and solder the signal leads to the remaining inner wire. Refer to your radio’s manual to determine which lead is what. To prevent water from entering the radio box I terminate the motor wiring outside, but close to, the box. The water could run inside the outer insulation into the box, as the motor end is exposed. For the rudder wiring I terminate the wiring inside the boxes. The outer insulated covering is run inside the boxes and sealed where it enters.

    To further protect the receiver from external noise use a Noise Trap between the rudder, and any other external long wire run servos, and the receiver. The noise trap is available at any hobby shop that sells radios and is made by Ace. The noise traps have to be soldered together, but it is a simple job. The noise trap is basically a digital integrated circuit that isolates the external wiring from direct connection to the receiver. Any noise that might be induced by external sources in the wires is absorbed by the circuit, not the more sensitive receiver. The noise trap is small and light weight, so it will easily fit in all but the most weight critical ships. If given a choice in these small ships between twisted pair wires and the noise trap, I would use the noise trap. If used outside a box be sure to seal the noise trap! Wire the noise trap so that it is close to the radio and the long wires then run from it to the servo.

    The antenna wire should be run up into the superstructure as high as possible, for maximum reception. If this is too unsightly buy one of the shorter mast type antennas (these are excellent) (Figure 2). The next best way to run the antenna is around the upper rim of the hull. This is more likely to pick up noise from the motors, and gets poorer reception. Never, never, never run the antenna in the bottom of the ship! The water acts as a partial shield and the antenna can be partially grounded out when water gets in your ship. Think of the antenna as a pair of binoculars, the higher they are the better you can see. Putting the antenna in the bottom of the ship is like standing in a deep hole with the binoculars and then throwing dirt on top!

Figure 2

    Now, how to power the receiver. Two options are available: a separate receiver battery, or the main batteries. The advantage of the receiver battery is that you are totally isolated from the main power. This cuts down, but not eliminates noise transmission. You are also assured that a wiring error will not fry your receiver, assuming you are using the manufacturer supplied battery. There are several disadvantages to using the receiver battery. One is that this adds the weight and bulk of the battery. Another is that you either have to seal the battery in the box (this protects it from damage) or leave it and the connector exposed to damage or disconnection due to shifting. If it is sealed in the box recharging is a pain. The last is that typically the receiver battery will not last as long as the transmitter battery. So, if you are not careful, you get to watch your ship drift helplessly through the enemy fleet (they will, however, thank you afterwards). One way to get around this is to have two packs and swap them. Be sure to write some sort of label on the batteries so that you do not reinstall the drained pack.

    The method I prefer is to run the receiver off the main batteries. The advantages of this are that as long as you have ship power your radio does too, there are no extra batteries to worry about, and with the slightly higher, but safe, voltage the servos operate a little faster. The only disadvantages are that you have to be very careful when initially wiring the circuit to get the proper voltage polarity and the receiver is a little more susceptible to noise and spikes on the power lines. The power line noise/spike problem can be all but eliminated by using the circuit shown. I will assume for the rest of the discussion that you are connecting to a 6 volt source. If your voltage is different you will have to use a commercial Battery Eliminator Circuit available at most hobby shops. These are effective at eliminating any noise in the line. However, they are overkill and operate on the edge of their capability for a 6 volt system, due to a minimum required voltage drop across the circuit. If you are using 12 volts made by putting two 6 volt batteries in series just run the radio off the battery connected to the negative lead.

    The schematic of the circuit I use to feed my receivers is shown in Figure 3. The nominal voltage of a fully charged 6 volt GelCell (the type I use) is 6.5 to 6.6 volts under a minor load. This is a little high for a receiver so a diode is put in line between the batteries and the receiver (see the schematic) this drops the voltage by about 0.7 volts. The diode has the additional benefit of preventing damage to the receiver if the batteries should accidentally be hooked up backwards in the future. Diodes are generally marked with a band on the end corresponding to bar on the diode symbol in the schematic. The larger capacitor (labeled with the + & - signs - 470 uf 35 volt) helps to filter out momentary voltage drops due to motor startup and the smaller capacitor (.047uf) filters out high frequency noise generated on the line from sources such as motor brush arcing.  For a more detailed description of this circuit and the need for filtering capacitors in general, see the Receiver and Solenoid Wiring section.

Figure 3

    The following fall under the category of general recommendations:

    To reduce the motor brush electrical noise induced into the wiring solder a capacitor, of the same range as the small ones in the circuit above, from each lead to the motor case and one from one lead to the other (Figure 4).

Figure 4

    To make maintenance and prelaunch setup easier I wire in a standard radio receiver switch between the batteries and the circuit with the switch mounted outside the box on the hull. This way I can turn the radio on/off with the deck in place. I mount the radio switch vertically using a DUBRO watertight switch mount with the ON position being pushed down (toward the deck) (Figure 5). This switch is impossible to shoot to the OFF position as I have seen happen with toggle or slide switches, no matter how well protected. In addition on the larger ships I mount an automobile type switch with a paddle handle and spade lug terminals to switch on or off the main battery power. I mount the switch horizontally with the paddle moving up and down. I use a DUBRO watertight fitting to hold a shaft that fits through a hole drilled in the paddle. This fitting goes through the deck and turns the switch on by pressing it toward the deck the same as the radio switch. With these switches I can load up the ship, screw the deck on, and be ready to start by just pushing down the switches. No last second pond side assembly required! This is especially useful if your ship is full of holes from the last sortie and you need to launch at the last second.

Figure 5

    This next recommendation is not so much for reliability, but for simple protection. Twice in my career as a skilled target I have had onboard fires caused by the pump. In the first a pump with a high performance motor ingested a vane and locked up. The motor overheated and caught fire. In the second I was using a phono-jack to power an indicator and the jack shorted melting a good portion of the wiring. To protect against this happening again, in addition to the power switches, I now fuse the main battery power and if weight allows the pump motor. For both fuses I use in-line automobile fuse holders. For the main power I use a 20 amp slo-blow fuse, and for the pump a 10 amp slo-blow. The reason I also fuse the pump is that this is the most likely to lock up and draw high current. If this happens I still have power to the rest of the ship to bring it in on its own. Unnecessary swimming is to be avoided! Be sure to use slo-blow fuses as a pump motor that draws 4 amps under load easily pegs my 10 amp meter for an instant on startup.

    The last topic in this section is the previously mentioned ground wire. The ship will be more immune to interference if it is "grounded" as this increases the efficiency of the antenna. Solder a single wire to all of your propshaft housings. Place a spade lug on one end and connect this to a mating lug on the negative lead from your batteries. This connects the ship to ground through the water and the connector allows the main wiring to be removed. Be sure that some of the metal is exposed to the water on the propshafts. When running and connecting equipment to the negative lead, run a single wire from the batteries through the box and on to the propshaft wire. Connect any separate negative leads to this wire, do not run a whole bunch of wires back to the batteries. The grounding will be more effective and the wiring much simpler and tangle free. Think of the negative lead as a clothesline and the equipment as clothes hanging on the line in order. For neatness consider this "clothesline" approach for the positive lead also.

    In addition you may wish to run this ground wire to the motor cases also. This is not required, but if you are having glitch problems it is a good first step to try.
 

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