Foam Boat From 3d Printed Thrusters and Workshop Scrap

Introduction:
The inspiration for this boat is a mixture of things. I have been wanting to make use of some old 3d printed ROV thrusters i've had laying around. I also just recently watched a video from RC test flight about his series of autonomous boats. Shortly after that I saw this contest and decided it was a calling to make an RC boat from the 3d printed propellers.

Supplies

• x2 3d printed* KORT nozzles
• x2 brushed speed controllers
• x2 3d printed* propellers (personal design, if there is interest I can find the files)
• x2 water proof connectors
• x2 bilge pumps with impeller housing and impeller removed
• x1 LiPo battery [3s, 11.6 v, 2230mAh]
• x1 APM 2.5 flight computer [Arduino based flight controller]
• x1 GPS
• x2 telemetry radios [433 MHz 100mw]
• large 1" thick foam insulation board

*Printed in ABS filament

Step 1: Designing the Hull

This boat's hull is based on a barge seeing as it will keep the boat stable and allow for a large distance
between the motors allowing greater turning power.

This design uses differential thrust in order to steer, minimizing components. Differential thrust works in by altering the thrust between two motors in order to control the craft's yaw. Due to this, the boat no longer requires a rudder, simplifying the design.

I used the box that used to house the APM and motor controllers in order to get a rough foot print for the electronics compartment on the boat. The electronics compartment is situated in the center of the boat measuring approximately 17" long, 9" wide, and 8" tall providing plenty of space for future shenanigans.

Step 2: Building the Hull

Required tools:

-Dull exacto knife

-Random knife I found in workshop when the exacto stopped working

-hot glue gun

-box cutter?

Process

The hull components were (slowly and painfully) cut out and glued together with the hot glue gun and some stupidly strong gorilla glue sticks.The motor mounts were then designed*, made, redesigned, hastily modified, then finally added to the boat. After the hull was complete a few quality passes were made trimming off excess flab (material) around the walls of the boat and electronics box to make it look a bit nicer and reduce excess drag.

*I was going to make the motors vector in order to gain more authority over the motors, however I deemed it too mechanically complex for the time frame I am working with.

Step 3: Electronic Fun!

Not really much to say here,

everything was wired per the diagram above, the telemetry components were wired to a box outside of the electronic enclosure to minimize any electronic noise that would interfere with the signal emanating from the motors or motor controllers. Especially since these are brushed motors.

Fun note:

Based on my research the current version of Ardu Rover is capable of driving my motor controllers, although as I later found out after the boat was complete my APM (sadly) cannot run the current version and due to that requires quite a workaround if I don't change the motors from brushed to brushless. This work around would entail the usage of an arduino to take the brushless motor controller signal from the APM and translate it to a signal for the brushed motor controller. If I were to perform this work around the boat would be controllable by both the RC controller and the the flight controller.

Step 4: ??? (Mission Planner Fun)

Mission planner is the software that is used In order to set up the APM, give the boat life, and make use of its numerous fun functions such as autonomous movement, remote monitoring of essential stats (battery, speed, etc..), and tricking the telemetry radios into working.

This software is also used for many other contraptions besides just boats. Such as planes, quad copters, ROVs (remotly operated submerged vehicles), rovers, and many others.

Step 5: Profit (testing and Project Completion)

As mentioned earlier, the boat cannot be controlled in its current state. However, I can remove the connection between the motor controller and the APM resulting in the thrusters being in constant full throttle. Using this I was able to test the hull and see roughly how it would perform.

I am happy I tested it in a small body of water nearby instead of in the lake. The thrusters were also balanced providing constant equal thrust, so the boat goes straight on its own and doesn't sink. Which satisfies the goal of the project; however I will surely be back to mangle together some arduino code so both I and the flight controller can actually control the boat.