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  #151  
Old 03-20-2017, 03:20 PM
kerosene kerosene is offline
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Torqeedo is kind honest in their 5.6kW claim (electric, gearing and prop losses accounted for) - they are trying to play to their strengths.
What is special on torqeedo is the planetary reduction gear so they can spin slower propeller thus giving better propulsion efficiency at slow speeds for a slow boat. If you want to go 10 knotts you will likely run out of pitch and lose badly to the out of the mill gas OB.
If the comparison would be with a high thrust OB torqeedo would likely lose for 10-15hp gas OB even at slower speed work. I am guessing 10kw continuous draw equalling about 10hp at shaft.

only truly honest comparison is shaft hp to shaft HP and if you have magical propeller with higher efficiency then explain that out separately.
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  #152  
Old 03-20-2017, 05:34 PM
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DennisRB DennisRB is offline
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A boating magazine did a test of small outboards gas vs electric. The gas motors destroyed the electric in performance. The claims were totally unfounded for the electric motors. They could not even match them kw for kw ket alone match gas obs with more power. This is obvious to anyone with any understanding of what power is.
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  #153  
Old 03-21-2017, 06:38 AM
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terhohalme terhohalme is offline
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One problem with the Torqeedo output power 5.6 kW is and that is propulsion efficiency. It will change a lot depending on boat speed, propeller pitch and diameter. They should have balls to tell the maximum continuous shaft power.
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  #154  
Old 03-21-2017, 02:13 PM
Stumble Stumble is offline
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Quote:
Originally Posted by terhohalme View Post
One problem with the Torqeedo output power 5.6 kW is and that is propulsion efficiency. It will change a lot depending on boat speed, propeller pitch and diameter. They should have balls to tell the maximum continuous shaft power.
It doesn't matter to them, because the 10kw input is the same as a 25hp output gas motor. So why get bogged down with detail and honesty?


Ok, I am going to sit in the corner for a bit and cool off. I despise the way electric outboards are marketed, and really wish just one of them would be honest about their performance.
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  #155  
Old 03-21-2017, 06:53 PM
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DennisRB DennisRB is offline
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The issue with using torque for a benchmark is that torque has no relevance in regards to time/speed. Motors are ALL about speed. They move boats through the water at a required speed. Therefore torque is useless.

Take the following example. A charter plate fishing boat with 3 x 300hp outboards is to engage in a pull test against an opponent to see what has more "thrust". The opponent is a strong dock cleat. In the test the dock cleat proved even with the 900hp! Neither was able to advance so it was a draw. We can now say the dock cleat is equal to 900hp! Well we can in electric motor advertising theory anyway.
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