Gather the necessary components (see Components section) and basic tools (glue, cutter, soldering iron, etc.). Familiarize yourself with the general project plan and hull dimensions.

Produce a first version of the hull in cardboard, to be used as a functional prototype. The dimensions of this hull are approx:

Length: 35 cm
Width: 12 cm
Height: 8 cm

Carefully assemble the walls with hot glue or waterproof glue, and provide a top opening for inserting the electronic components.

Fasten all components inside the hull, following the diagrams in the project logs.

The motor is positioned aft and submerged.

The servomotor is connected to the rudder.

The Arduino and battery are positioned centrally to ensure good balance.
Brackets and housings are made as required, in cardboard or printed parts.

To avoid direct drive and make propulsion more realistic and efficient, we implemented a gear system between the motor and propeller. Two gears were designed and 3D printed: the first, 60 mm in diameter, is fixed directly to the motor shaft; the second, 80 mm in diameter, is mounted on an independent shaft connected to the propeller. (see files)

Make the electrical connections, following the examples and photos documented in the logs.

1. DC motor connection via L298N

- DC motor: Connect the two motor leads to terminals OUT1 and OUT2 on the L298N.

- Motor power supply: Connect the VCC terminal on the L298N to the positive terminal of your external power supply (e.g. +9V), and the GND terminal to the negative terminal (0V).

- Control pins from L298N to Arduino :

IN1 → Arduino pin D2

IN2 → Arduino pin D3

- ENA (Enable A) → Arduino pin D5 (PWM)

- L298N logic supply:

If your motor supply is 12V or less, place the jumper on the L298N's 5V regulator to supply the internal logic.

Otherwise, supply 5V to the L298N's 5V terminal from the Arduino or another regulated source.

2. Connecting the servomotor to the Arduino
- Signal wire (usually orange or white): Connect to pin D9 on the Arduino.

- Power lead (red): Connect to a regulated 5V source. Avoid using the Arduino's 5V if the servo draws a lot of current.

- Ground wire (black or brown): Connect to the Arduino's ground (GND).

3. Ground connection
Make sure that all grounds (GND) of the Arduino, L298N, external power supply and servo are interconnected to ensure stable operation.

The code required to operate the boat is available in the Files section. It controls propulsion, steering and the reception of remote commands.

Test under real-life conditions. Check propulsion and steering for stability, responsiveness and correct operation.

If the hull is made of cardboard, avoid prolonged contact with water: this version remains a prototype.

For a more advanced version, reuse the same system with a fully 3D-printed hull (see version V2 in the logs). This makes the project even more waterproof and durable.