Hi Dan,
But when you read the article, did you think that they meant 4kts when they said the hydrofoil has a 100km range? That they meant at less than 10% throttle? To me that's a little extreme... I would have preferred a range quote for "cruising" speed, what ever that might be for this little, sporty hydrofoil. Cruising range is an accepted industry measurement for recreational trawlers and cabin cruisers, and they don't mean at 20% of top speed.
Eric
Marina del Rey, CA
--- In electricboats@yahoogroups.com, danbollinger <no_reply@...> wrote:
>
> But isn't this true for all motor boats? The maximum range is at the speed at which that range is obtainable, never full throttle, but somewhere around half that. What I'm saying is that their statement isn't misleading, but rather a common industry measurement. There's no need to read between the lines, just read the lines with the meaning they are intended to convey.
>
> --- In electricboats@yahoogroups.com, "Eric" <ewdysar@> wrote:
> >
> > Hi Kirk,
> >
> > And this is another example of somewhat misleading promotional information. One has to read between the lines. The 100km range is not at 40kmh. The motor pulls 3.7kW and the battery pack is only rated for 4.5kWh. If we assume a safe discharge to 80% DoD, the battery has 3.6Kwh usable, which works out to 54 minutes (using Peukert's exponent of 1.03 for the Li-Ion batteries) from full to empty at full speed. This pegs the range at 36km or just under 20nm at 40kmh/22kts.
> >
> > To get to 100km using 100% of 4.5kWh, one needs to drop the discharge amps to 6.5A, which should deliver about 4kts (according to specs derived from Torqeedo's published data) and in almost 14 hours, one will have travelled 55nm which is roughly 100km.
> >
> > That just doesn't sound as exciting as the original headline.
> >
> > That said, it does look like a fun toy, and certainly much cheaper than the all electric ski boat discussed a few months ago.
> >
> > Fair winds,
> > Eric
> > Marina del Rey, CA
> >
> > --- In electricboats@yahoogroups.com, Kirk McLoren <kirkmcloren@> wrote:
> > >
> > > sorry, 100 kilometers
> > > Â
> > > ... How beautiful it is to do nothing, then rest afterwards
> > > Â Â Â Â
> > >
> > >
> > > ________________________________
> > > From: Kirk McLoren <kirkmcloren@>
> > > To: "electricboats@yahoogroups.com" <electricboats@yahoogroups.com>
> > > Sent: Thursday, May 17, 2012 11:22 AM
> > > Subject: [Electric Boats] hydrofoil 100 mile range
> > >
> > >
> > > Â
> > > http://www.gizmag.com/quadrofoil-electric-hydrofoil-watercraft/22560/?utm_source=Gizmag+Subscribers&utm_campaign=4b1188da1b-UA-2235360-4&utm_medium=emailÂ
> > > Â is this great or what?
> > > ... How beautiful it is to do nothing, then rest afterwards
> > > Â Â Â Â
> > >
> >
>
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