Toy Submarine

Introduction

This article presents a few ideas on how to make a DIY toy submarine.

To make a toy submarine you need at least one water tank that will be filled with water to allow submergence of the submarine. You will also need an electric water pump that will pump water inside the tank to increase the submarine weight and to allow submergence. The submarine can rise to the surface when the pump spins in a different direction and pumps all the water out.

There could be issues with the air pressure forces when the water is entering the tank or lack of pressure forces when the water is leaving the tank (vacuum). The solution to this problem is filling the tank with just about enough water to allow submergence.

From this basic idea, a number of different toy submarines can be made.

Non-Fully Sinking Submarine

This is a very simple design where a water pump remains on the surface at all times. This is the cheapest design. You can make a submarine looking like a toy submerging oil rig. Advantages include not having to pay for waterproof:

- motor,

- electrical system (wiring),

- battery.

However, this toy can only be used in bathtubs, sinks or buckets. You will be able to take this toy to the lake or deep swimming pool.

Manual Pressure Pumps

You can use a manual pressure pump and a servo motor control attached to pull the pump, draw water inside and allow sinking of the submarine. The water pump can be divided into to fully waterproof/water isolated sections. One to section will remain fully waterproof with only air inside and another will take in water. This pump is similar to tire pumps, hydraulics, or big syringes. This design is the second cheapest and will allow full submergence of the toy submarine because you can put the entire servo motor and the electrical system inside the waterproof part of the water tank. The problem with this design is the need for high force and high current from the servo motors.

Automotive Windscreen Water Pumps

This is the most expensive and the best idea in my personal opinion. The windscreen water pumps are made to isolate the water inside the tank from the electrical motor. Then the only challenge is waterproofing the electrical wiring. The submarine will sink by default if the motor is OFF because water will be entering the pump and rise to the surface when the motor pumps all the water from the tank.

Conclusion

I have not tested any of those ideas. If you have the money you can send me your photos and videos.