Close

Monohull Design

A project log for Low-Cost, Waterjet-Powered Robotic Speedboats

This project focuses on the development of open-source, low-cost, waterjet-powered robotic speedboats for education and research

New DexterityNew Dexterity 10/13/2021 at 14:220 Comments

It was the easiest to design and implement as it was only one hull and therefore only required one jet propulsion system}. The boat was capable of rolling as the vectoring nozzle rotated which reduced the turn radius of the boat making it very maneuverable. However due to its roll it produces an unsteady surface for the camera and LiDAR which results in unusable footage and LiDAR data. Therefore it was used to validate that a 3D printed hull would be durable, buoyant and waterproof enough. It also allowed for testing of propulsion systems on open water in dynamic testing rather than just stationery.

Construction

The monohull boat is printed from PLA on a larger than standard printer in two 400mm long sections that were then bonded together using epoxy. Due to the size of the printer a 0.5mm layer height was used which resulted in a rather rough finish but it would for the hull. The inlet for the jet housing was printed separately as it needed to have a much smoother surface finish. It also was done separately so we could iterate through different inlets on the boat. Custom laser cut gaskets were used to seal it however, they didn’t work where it joined with the back of the boat. This was due to the high pressures created from the impeller. Therefore it was just siliconed in. 

To help mitigate the roll of the boat on the camera footage a simple 2 axis gimbal was designed however due to the speed of the boat the cheap servos didn’t work well enough.

Testing

Tub testing

Pool testing


Pond Testing


Discussions