The recommendation from Electric yacht for their 5kw motor is up to 28 ft and 7000 lbs replacing up to 15 shp ICE and up to 34 ft with 12000 lbs. 6 tons replacing up to 25 SHP. They currently offer a 20kw unit for up to 42 ft. and 11 tons. I imagine hull shape will have something to do with the actual requirement and the resulting performance. I'm still a novice with electric power. If I was building a displacement hull I would follow the recommendations of the naval architect at this point for gas/diesel.
To: electricboats@yahoogroups.com
From: ewdysar@yahoo.com
Date: Wed, 27 Mar 2013 23:42:08 +0000
Subject: [Electric Boats] Re: does anyone have current real world performance figures please
To: electricboats@yahoogroups.com
From: ewdysar@yahoo.com
Date: Wed, 27 Mar 2013 23:42:08 +0000
Subject: [Electric Boats] Re: does anyone have current real world performance figures please
BTW, the recommendation of 1kW per ton of displacement has proven to deliver about 90-95% of theoretical hull speed on a number of different displacement hull shapes and sizes. That statement is accurate for my inflatable dinghy with a Torqeedo and for my 30' 5.1 ton ketch. A number of other conversions reported here fall into the same range. This does assume a drive (motor through prop) that is matched to the desired speed as discussed in my recent threads.
Eric
--- In electricboats@yahoogroups.com, "Eric" <ewdysar@...> wrote:
>
> Hi Pamela,
>
> While that is true, the speeds that we're talking about (less than 95% of displacement hull speed) are considered the sweet spot. Specifically, the 6kt speed that we're discussing with Julian is 80% hull speed.
>
> Trying to get all the way to or past hull speed can take very large amounts of power in a displacement hull and that's where diminishing returns really start to take hold. To date, I've never recommended that anyone try to get to hull speed in displacement mode with an electric conversion.
>
> Fair winds,
> Eric
>
> --- In electricboats@yahoogroups.com, Pamela Tilstra <pamlt@> wrote:
> >
> > While you're stressing about prop speed and hull speed, ermember the law of diminshing return. There is a point where you get little or no performance experience. only greater expense or less efficient power usage.
> >
> >
>
Eric
--- In electricboats@yahoogroups.com, "Eric" <ewdysar@...> wrote:
>
> Hi Pamela,
>
> While that is true, the speeds that we're talking about (less than 95% of displacement hull speed) are considered the sweet spot. Specifically, the 6kt speed that we're discussing with Julian is 80% hull speed.
>
> Trying to get all the way to or past hull speed can take very large amounts of power in a displacement hull and that's where diminishing returns really start to take hold. To date, I've never recommended that anyone try to get to hull speed in displacement mode with an electric conversion.
>
> Fair winds,
> Eric
>
> --- In electricboats@yahoogroups.com, Pamela Tilstra <pamlt@> wrote:
> >
> > While you're stressing about prop speed and hull speed, ermember the law of diminshing return. There is a point where you get little or no performance experience. only greater expense or less efficient power usage.
> >
> >
>
__._,_.___
| Reply via web post | Reply to sender | Reply to group | Start a New Topic | Messages in this topic (26) |
.
__,_._,___
No comments:
Post a Comment