DIY 20km/h Electric Jet Boat

[Leo1121]

Hey guys,

I'm new to this forum, currently building an electric jet boat and I'm encountering some issues with speed. I'm only able to reach 10 km/h with the following specifications. Could anyone help me identify potential problems?

I hope to achieve a speed of 20 km/h with my jet boat, but I feel that the thrust produced by the pump is not as strong as I expected. Even though I’m using a 7 kW motor, it doesn’t seem to be operating at full power. I’m unsure why this is happening or how to increase the thrust to reach that 20 km/h speed. I would appreciate any help or advice!

Specifications:

• Lithium Battery: 60V 35Ah 175A
• ESC: APISQUEEN 12S 160A
• Motor: APISQUEEN 130KV 7kW 48-70V
• Link: APISQUEEN Motor
• Boat Size & Weight: 2m x 1.2m, 50kg
• Water Jet Pump & Impeller: (attached photo) 70mm Diameter impeller

Thanks in advance for your help!

 

[Quinc]

How many rpms is your motor spinning under load? Also that impeller/pump setup is tiny. For my small jetski I am running a 140mm pump and reaching around 25mph with a 90lb rider.

Electric standup jetski build

Built this over the winter with my 8 year old. He took every nut and bolt off the ski and did the fiberglass! So please give him a like and sub on youtube. :) Couple things I could use some help with. My Ant bms/battery only charges to 4.158 per cell. Any tips on getting it to charge up to the...

endless-sphere.com

 

[gromike]

You do have a volt and amp meter on the power supply? If so, what are they under full load?

 

[Otto44]

Nearly the same size I ave built a jetboat for my daughter.

I designed the jet, here you can find it.

Water Jet propulsion unit

Running: https://www.youtube.com/watch?v=cvIoHMibZx4 https://youtu.be/NewKjySw2ko Steering https://youtu.be/DfDibsSg9Ow This is my completely new design 50mm Water Jet. It has better bearing support for the shaft, integrated cooling supply, intergrated grease nipples, better flow..... You get...

cults3d.com

here is the boat in action. i used a 56115 innerrunner on 12S lithium battery. Powerinput was around 4,5kw. So you should be able to get much faster than 10Kmh

 

[Hillhater]

The boat weight ay only be 50 kg, but with someone on board the total weight will more than double.
jet drives are VERY sensitivw ti the clearance between the ompeller tips nd the housing…less is best
their performance efficiency drops dramatically as the clearance widens . 0.5 mm would be a good target.
And obviously hull shape will determin max speed if you dont get on to planing .