RC Boat

https://youtu.be/d0IpHtbU63A

This is fully functional RC boat that I made from scratch. It was inspired by commercial RC speed boats.

Parts list:

• 3D printed parts from files. I printed them on Zortrax M300 and they were watertight. There are no special recommendations for print settings, just check if you are able to print whole parts. If not try to resize equally or divide. I also printed larger version, the one that you can see on pics
• M4 235mm boat shaft (self sealing)
• M4 30-35 boat screw (you can start with cheap screw, more expensive do not produce significantly higher trust)
• 4x5 metal kardan joint
• 20-30 ESC
• 2205 2300kV motor (I had this one, you can try another one)
• servo 9g (for the start it can be plastic servo, but I recommend metal servo)
• lipo 1300 - 2200 mah, 3-4 S
• transmitter and receiver (2 channel is enough for start)
• hot glue
• sanitary sealant (cheapest silicone is ok)
• zip ties
• some screws

1. Print all parts. Check if printed parts are watertight. If not use sanitary sealant or another sealant
2. Make a sealant between hull and lid from sanitary sealant or another sealant
3. Make test in bathroom if the boat is watertight. If there will be some drops of water, do not worry, for the beginning it is enough
4. Make a rudder: I did not design its parts because I had aluminum hotend block, flat plastic part, PTFE tube from printer and screws. Try to make yours from scrap. Use metal pushrod for connecting servo inside the hull with rudder. You need to experiment a little to set the proper length of rod.
5. Combine all the parts together.
6. For start test the boat in bath. You do not want to sink your precious boat on first run ;)

Upgrades:

1. Depending on water and air temperature, your ESC and motor can warm up significantly so it will reduce its power. So remember not to boil them up. I recommend adding 40x40 fan blowing on ESC inside the hull. More professional but also more expensive will be replacing motor and ESC with version with water cooling made especially for RC speedboats.
2. You can see on the movie, the boat screw is sucking air on higher speeds. I suppose this is due to hull shape and how deep is the screw in water. When I lowered the screw the boat was faster but also more prone to roll-over.
3. It will be good to have anti rollover system. It happens on the greater speeds. Commercial RC speedboats have reverse thrust which helps roll back. Of course screw needs to be immersed in water when boat is on its back. Lowering the center of gravity of boat will also help to stabilize the boat
4. You can experiment with different rudder size, I believe it will improve performance on taking fast turns.
5. You can add additional fins for more stability.

Let me know in comments what do you think, how can performance be improved.