Below you will find pictures and explanations of the PCB. The PCB holds the dual water detector, which monitors water intrusion in WTC1 and WTC2, with automatic surfacing. Also on this pcb is the 2Hz generator for the top light. (I have the rest of the light controlling electronics in a small box elsewhere in the hull.) The PCB is mounted in WTC2.

The two red LED's indicate if and where water is detected. (WTC1, WTC2)
The green LED is the power indicator.

Schematics for the water alarms available here.
Schematics for the 2Hz flasher available here.

R/C components, details, pictures & data:

Engine:

The engine for the propeller needs to have a high degree of reliability. Do your self the favor and use a Graupner engine for this task. They come highly recommended, have years of experience in this field, and are not even expensive. After talking to other subbers, I found that the propeller RPM should be somewhere between 5000 and 6500, and that it's a good idea to use a gear box instead of finding an engine with this RPM. The reason is that using a gearbox gives the engine a little more torque, than if it was directly connected to the propeller.  I decided to use the Graupner engine "Speed 600BB" (BB for Ball Bearing). The technical data are as follows:

Type:

Graupner part no.

Nominal voltage:

Voltage range:

No-load RPM:

No-load current:

Current @ max. effic.

Stalled Current:

Max. efficiency:

Case length:

Case diam:

Free shaft length:

Shaft dia.

Weight:

Speed 600BB

M-6310

9.6V

7.2 - 12V

17.000

0.8A

6.6A

55A

75%

57mm

35.7mm

11.9mm

3.17mm

194g.

Gears:

My propeller shaft is supported by a ball bearing with a flange (from an old hard disk) and the stuffing box. This enables me to go without the normally used bearing houses, and offers a low friction fitting, saving battery power an reduces engine heat.

Regulator:

You will also need a regulator in front of the engine, and here I can suggest "Navy V40R" from Graupner, but this is not a critical choice. (The V40R runs on 4.8 -> 16V) Ask your local dealer for advice, and availability. Remember that it must be able to reverse the engine, be temperature protected, and capable of surviving the stall current of the engine. (If you travel forward, and then go directly to reverse without allowing the engine to stop first, then the stall current will be drawn for a short period of time.) The Navy V40R delivers 5.5V (via the BEC) to the receiver and the two servos, so this also solves the problem concerning the voltage for these components. All though the Navy V40R is watertight, and can be placed outside your WTC, I do not recommend this. The reason is that the minimum temperature for some reason is as high as 15*C, a temperature that the water hardly ever is deeper down in my part of the world. Failure in this component will be devastating, as it is the power source for the receiver etc. If, nevertheless, you decide to place it in the cooling water outside your WTC, remember to make the connections watertight as well.  The technical data are as follows:

 

Type:	Graupner part no.	Voltage range:	Current not cooled	Current water cooled	Current < 10s	Battery Elimination Circuitry out:	Height:	Length:	Width:	Weight:
Navy V40R	2875	4.8 - 16V	40A	60A	120A	5.5V 3A (Shortly)	13.5mm	60mm	29mm	30g.

Servos:

The rudder movements are controlled by two individual servos, located within the same WTC as the engine and the electronics etc. They need to be able to push / pull the rods back and forth, and the below described servos should be suitable. The servos for the rudders needs to have a high degree of reliability. Do your self the favor and use a Graupner servo for this task. They come highly recommended, have years of experience in this field, and are not even expensive. I decided to use the Graupner servos "C261" (w. reinforced gearbox). The technical data are as follows:

Type:

Graupner part no.

Voltage range:

Current inactive:

Current active

Force: Ncm

Force: Kg

Active angle:

Speed:

Height:

Length:

Width:

Weight:

C261

5125.L

4.8 - 6V

5mA

0.45A

14

1.4

-45* to + 45*

0,14 s/40°

21mm

22mm

11mm

8g.

Small switches:

Two small switches are needed to send the signals to "Remote Dive" and "Remote Surface". Again, Graupner has something that we can use: The Graupner Mini Switch. On the remote, two spring operated push buttons are placed, and labeled "Dive" & "Surface" These then momentary enables the two switches at the end of the receiver. More of these might be needed, if you choose to build the navigational light control, as well as other options. The technical data are as follows:

Type:	Graupner part no.	Voltage range:	Current inactive:	Current active	Height:	Length:	Width:	Weight:
Mini Switch 40	3294	7.2 - 14V	0	0.08A	32mm	30mm	15mm	45g.

Bow thruster control:
 

The left-right movement of the throttle stick operates a small controller for the bow thruster. This function can be mixed into the rudder channel at the remote, thus making the thruster 'automatic', trailing the rudders. The controller for the bow thruster pump is a brilliant little thing from SubTech: the RS-5.  "The RS-5 Switch is ideal for applications that require reversing the rotation of small electric motors such as ballast pumps, bow thrusters, fire pumps etc. Provides Forwards-Off-Reverse functions. Microprocessor control and low “on” resistance Mosfet assures reliable, efficient operation. Will control 2 volt - 12 volt motors at a maximum of 5 amps." Available through Pandan Models, UK.

Type:	SubTech part no.	Voltage range:	Current inactive:	Current active	Height:	Length:	Width:	Weight:
RS-5	RS-5	2 - 12V	?	Max 5A	19mm	38mm	38mm	?g.

Transmitter:

The transmitter needs to be able to handle the following functions: Engine forward / reverse, rudder up / down, rudder port / starboard, Remote Dive and Remote Surface. This is 8 functions, demanding 5 channels. In addition comes the control of navigational light, missile / torpedo firing etc, and thruster if fitted. (Note that Graupner uses the term "Channels" somewhat different than everybody else.) The Graupner kit MC12 with expansions can handle what we need. Please refer to the chapter Remote Control Configuration for details. The technical data are as follows:

 

Type:

Graupner part no.

Voltage range:

Freq.

Channel grid:

Output P:

Max. channels:

Temp. range:

Antenna length:

Height:

Length:

Width:

Weight:

MC12

Gr4724

9.6 - 12V

40 MHz

10 kHz

2W

7

-

1150mm

75mm

175mm

190mm

950g.

Receiver:

The receiver needs to be able to handle the following functions: Engine forward / reverse, rudder up / down, rudder port / starboard, Remote Dive and Remote Surface. This is 8 functions, demanding 5 channels. (Note that Graupner uses the term "Channels" somewhat different than everybody else.) R700 can handle what we need, and even leave two channels available for future use. The technical data are as follows:

 

Type:

Graupner part no.

Voltage range:

Freq.

Current

Channel grid:

Sensitivity:

No. of servos:

Temp. range:

Antenna length:

Height:

Length:

Width:

Weight:

R700

Gr3551

4.8 - 6V

40 MHz

13mA

10 kHz

10µV

7

15* to + 55*

950mm

16mm

47mm

25mm

16g.

Images of the installed components can be seen here, along with the electronics-, battery- and A.L.T. mechanism section.