Self-Assembled Watercraft without Wires: The Guide to Building Your Own Underwater Scooter
================================================================================
In August 2025, a DIY enthusiast named Ben showcased an impressive project—the creation of a fully waterproof, hermetically sealed 3D-printed underwater personal propulsion device, or sea scooter. This innovative sea scooter, built with print-in-place electronics and a magnetic control system, is a testament to the growing potential of 3D printing technology.
Designing for Print-in-Place Assembly
The key to achieving a watertight sea scooter lies in print-in-place assembly. Ben designed the entire hull and mechanical interfaces (shafts, connectors, and seals) to be printed in one continuous print job with no post-printing holes. During the multi-hour print, he paused the 3D printer at predefined layers to manually drop in pre-assembled subsystems such as the motor, electronics, battery pack, wireless charging coils, and magnetic gearbox. After resuming printing, these components were sealed inside the hull, creating a hermetic enclosure.
Embedding Electronics
Embedding all electronics, including the motor and batteries, directly within the print was another crucial step. Ben used custom battery packs, such as an 8S LiFePO₄ battery, designed to fit inside the sealed cavity. Wireless charging coils were installed inside the hull to enable charging through the hull without penetration points.
Magnetic Control System
Given that WiFi and Bluetooth signals are unreliable underwater, Ben opted for a reed-switch-based magnetic control system for non-contact operation. This magnetic control also enabled the use of a magnetic gearbox to transfer torque without any physical shaft penetrations through the hull, thus maintaining full watertight integrity.
Waterproofing and Hermetic Sealing
After embedding all components and completing the print, Ben coated everything with epoxy resin to further seal and reinforce the hull, creating a robust submarine-like enclosure. The print-in-place method with embedded components and magnetic non-contact drives completely avoided any physical shaft or cable penetrations, the main potential leak points in underwater devices.
Materials and Printing Considerations
To ensure the success of his sea scooter, Ben used high-quality filament suitable for underwater use and capable of forming watertight layers, such as PETG or ABS with proper print settings. Precise print calibration was essential as the embedded components and mechanical hinges/pivots required exact tolerances to function after printing. The entire print could take 14+ hours, and any print failure mandated starting over due to the embedded components, so reliability in printing was critical.
Conclusion
By combining print-in-place embedding of components, non-contact magnetic control, wireless power transfer, and epoxy sealing, Ben successfully built a hermetically sealed underwater personal propulsion device fully 3D-printed in one go with print-in-place electronics and controls. This approach was documented in a Hackaday 2025 project article, detailing the complete process and challenges of building a DIY sea scooter using these methods.
Readers are encouraged to discuss the possibilities of building one themselves and explore the exciting potential of 3D printing technology in creating innovative underwater devices.
[1] Ben. (2025). Building a Waterproof Sea Scooter with 3D Printing: A DIY Project. Hackaday. Retrieved from https://hackaday.com/2025/08/15/building-a-waterproof-sea-scooter-with-3d-printing-a-diy-project/
[3] Ben. (2025). Sea Scooter 3D Printing Files. Thingiverse. Retrieved from https://www.thingiverse.com/thing:5491439
- Ben's innovation in creating the waterproof sea scooter extends beyond just the mechanical aspects; he also integrated smart-home devices by embedding wireless charging coils within the hull for charging the battery pack.
- As the world continues to evolve with technology, Ben's underwater personal propulsion device demonstrates the potential of 3D printing in not only electronics but also in the development of gadgets like the sea scooter, pushing the boundaries of what is possible in the realm of advanced technology.
