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Whimsical · 08-01-2007, 06:18

Hi guys.
I have been lurking here for some time but now must open my mouth.
I have started construction of a Schioning 12.3 Wilderness. Hope to launch early next year.
There are threads here and at other sites that I have been following with great enthusiasm for the obvious reasons. What I have not yet been able to develop however is a sense of equivalency between electric and diesel motors.

In my case twin 20 Hp diesels are appropriate, which equates to 6.5 Hp/ton, so I will work from this.
Fey on their site suggest diesel Hp x .7 or 14 Hp (10 kW). http://www.feys.org/System/our_system.htm
This seems to be the high end with Re-e-power at the other http://www.re-e-power.com . The 4000 to be equivalent to 40 Hp thus the 3000 is equivalent to 20Hp which is 3800 w continuous. Quite a large variation.
The Lagoon is using 10 kW motors but this weighs "Max displacement (EEC) 12,800 kg / 31,800 lbs" (from the site Lagoon 420 - New Catamarans - The Catamaran Company ). An error here, is it 12,800 kg and 28,000 lb or 14,454 kg and 31,800 lb. Take the middle ground and say 13,600 kg with 20 kW or 680 kg/kW. Equate this to my max displacement of 6350 kg and we have 9.3 kW. Twin Re-e-power 3000s is 7.6 kW, a bit short of the lagoon but a lot closer than the 20 kW suggested by Fey’s formulae. Given Lagoon’s research and development with Solomon I would doubt they would be severely under powered so I have used this as the starting point for an existing vessel. Information on other vessels that actually exist seems sketchy at best.

If the Lagoon was powered conventionally at 6.5 Hp/T we get 88 Hp or say twin 40’s. Does this seem reasonable?
Are there any reports on the electric Lagoons performance in various sea states?
Are there any reports on other vessels where enough data is available to further my comparison?
Any more manufacturer sites that may help fill in my blanks, either motor suppliers or boat manufacturers.

Most of the info is splattered around so maybe this thread could form a point of focus.
Mods how about a specific forum for electric prop and related equipment as it will end up across several poorly related places.

08-01-2007, 06:18	#1
Whimsical Registered User Join Date: Jan 2007 Location: Fremantle Australia Boat: Schioning 12.3 "Wilderness" Bi-Rig under construction Posts: 520	Electric and Diesel comparison Hi guys. I have been lurking here for some time but now must open my mouth. I have started construction of a Schioning 12.3 Wilderness. Hope to launch early next year. There are threads here and at other sites that I have been following with great enthusiasm for the obvious reasons. What I have not yet been able to develop however is a sense of equivalency between electric and diesel motors. In my case twin 20 Hp diesels are appropriate, which equates to 6.5 Hp/ton, so I will work from this. Fey on their site suggest diesel Hp x .7 or 14 Hp (10 kW). http://www.feys.org/System/our_system.htm This seems to be the high end with Re-e-power at the other http://www.re-e-power.com . The 4000 to be equivalent to 40 Hp thus the 3000 is equivalent to 20Hp which is 3800 w continuous. Quite a large variation. The Lagoon is using 10 kW motors but this weighs "Max displacement (EEC) 12,800 kg / 31,800 lbs" (from the site Lagoon 420 - New Catamarans - The Catamaran Company ). An error here, is it 12,800 kg and 28,000 lb or 14,454 kg and 31,800 lb. Take the middle ground and say 13,600 kg with 20 kW or 680 kg/kW. Equate this to my max displacement of 6350 kg and we have 9.3 kW. Twin Re-e-power 3000s is 7.6 kW, a bit short of the lagoon but a lot closer than the 20 kW suggested by Fey’s formulae. Given Lagoon’s research and development with Solomon I would doubt they would be severely under powered so I have used this as the starting point for an existing vessel. Information on other vessels that actually exist seems sketchy at best. If the Lagoon was powered conventionally at 6.5 Hp/T we get 88 Hp or say twin 40’s. Does this seem reasonable? Are there any reports on the electric Lagoons performance in various sea states? Are there any reports on other vessels where enough data is available to further my comparison? Any more manufacturer sites that may help fill in my blanks, either motor suppliers or boat manufacturers. Most of the info is splattered around so maybe this thread could form a point of focus. Mods how about a specific forum for electric prop and related equipment as it will end up across several poorly related places.