5-Meter Power Cat with 6kW Outboard

[bobkart]

An E-Tech supplier answered that their motors can be configured to rotate in the other direction (left-handed). My next question was about efficiency, but they've not answered that yet (electric power in to prop-shaft power out).

And Propel got back to me about their S1 motor, specifically, about how their propeller design can support a wide thrust/speed range of applications, from tugboat to fast planing hull:

Our unique pancake motor delivers high torque at a low rpm. Using high-end computational fluid dynamics, we designed the most efficient motor in the industry. We found the optimal balance between propeller size and motor performance. It’s a motor with high peak efficiency & broad efficiency map, and low and safe voltage. We also developed a closed loop cooling for enduring continuous performance.

Seems straight out of their literature. I suppose I could try asking for a plot of that 'broad efficiency map'.

 

[bobkart]

 

[bobkart]

I just got an update from Propel:

The efficiency given is based on propulsive power and includes the complete power train. We're validating the current prop designs and I hope to be able to share more detailed numbers as soon as we completed the full validation.

I'm still unsure if this is overall efficiency (electrical power in to thrust out) or starting from the motor output. I.e. is the motor efficiency included in the 73.5% claimed. I'll update again if/when I hear further from them.

 

[bobkart]

On a re-read of what Propel wrote, "includes the complete powertrain" indicates to me that motor efficiency is included. Had it said "includes the complete drivetrain", I would want to factor in motor efficiency to that 73.5% to get overall efficiency. As I read it, the 73.5% is overall efficiency, which is impressive. I think that puts the propulsive power of the Propel motor on par with a 20hp ICE outboard, perhaps even higher.

Another part of their reply to my questions indicated that they are leaning towards a three-pitch selection of propellers, similar to how Torqeedo does it.

 

[bobkart]

 

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She finally got her name applied.

 

[bobkart]

Working on a second, smaller battery, for use as either backup battery (5.376kWh), or to add to the main battery for more range (156 minutes of full power). Could also be used by itself for short outings (~50 minutes of full power).

 

[bobkart]

 

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[bobkart]

First saltwater cruise:

 

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[Flotation]

Thanks for documenting and sharing your work. Perhaps a video more focused on the technical details of your electric cat would be nice? It would be good if those details reach a wider audience.