# YouTuber builds fully functional submarine out of Lego and takes it underwater

> Source: <https://www.dexerto.com/lego/youtuber-builds-fully-functional-submarine-out-of-lego-and-takes-it-underwater-3406594/>
> Published: 2026-09-07 20:06:31+00:00

A YouTuber has taken Lego engineering underwater, building a 6.5-pound radio-controlled submarine packed with functional [Lego](https://www.dexerto.com/lego/) Technic components.

Brick Experiment Channel has spent years developing and testing different versions of the homemade submarine, gradually adding more advanced systems with each iteration. Its latest creation, dubbed Submarine 5.0, successfully navigated both a swimming pool and a fast-flowing river.

The new version weighs 6.5 lbs and uses an acrylic hull, but much of the hardware controlling its movement has been built or modified using Lego parts.

## Lego submarine gets ballast system and moving weights

One of the biggest changes is how the submarine controls its depth. Earlier versions used a syringe-style piston to pull water into the vessel, but Submarine 5.0 instead uses a modified peristaltic pump to fill a 50 ml IV bag.

The flexible bag acts as ballast while taking up less valuable space inside the submarine. The pump itself was also modified with Lego components to work with the rest of the build.

Brick Experiment Channel used that extra room to add a new pitch control system. A total of 3 lbs of tungsten pellets sits on a motorized track inside the submarine, allowing the weight to slide forward or backward.

Moving the submarine’s center of gravity causes its nose to tilt up or down. Combined with forward movement, this lets the vessel dive and surface much faster while giving the creator greater control underwater.

Submarine 5.0 also replaces the Raspberry Pi Zero used in earlier builds with an Arduino Nano ESP32 microcontroller. It’s paired with a six-axis gyroscope and accelerometer, pressure sensor, and 40MHz radio receiver to handle proportional controls and communication underwater.

All of the equipment was squeezed inside a 250 x 120 mm acrylic tube powered by a 9V Lego battery box.

The creator also addressed a problem that appeared during testing of previous versions. Their flat fronts caused the submarines to veer sideways at higher speeds, so Version 5.0 received a rounded 4.72 inch plastic nose designed to improve its movement through the water.

After pool testing, Brick Experiment Channel took the finished submarine to a river, where it completed an underwater run at a depth of around 4.9 feet while fighting against the current.

Brick Experiment Channel isn’t the only creator taking Lego builds to extreme lengths. YouTuber Bricked MC previously went viral after [promising to recreate GTA 5’s sprawling map](https://www.dexerto.com/youtube/lego-youtuber-goes-viral-after-promising-to-build-full-replica-of-gta-5-map-3172695/) using more than 76,000 Lego bricks, with fans even donating money to help fund the massive project.