Thursday, May 17, 2012

Re: [Electric Boats] hydrofoil 100 km range at 4kts (or 7.4kmh)

 

I like it, and also totally agree with Eric, as well as other comments about the item
(on the article) and its short range.. thats a bummer.
 
different materials cutting the price in half would be a good start, it wouldnt take much of anything speed increase for the small amount of weight it might gain.
 
it comes with solar panels to charge it.. excuse me, whoopity-doo to that!
if you're stranded someplace a couple little panels are gonna take forever to do anything for ya, and they're not cheep either, if I were in an emergency situation I think I'd rather have a pedal powered generator, which could also be used at whim for extended range running.
it'd probably be cheaper and more practical, what if its dark out or theres clouds?
thered be losses of course, but with a flat battery you might be able to pedal 3 mph, and if all else fails does the thing come with a set of oars?
 
I still like it, think its plenty cute, and it has lots going for it as a concept, smooth riding in choppier stuff in a light craft, definite bonus. the range thing.. at its max efficiency speed, is that 100km with 1 or 2 aboard? a few stops and starts is probably gonna cut the range down lots in a hurry, I'm sure shoving it up onto its foils is a big hit to its battery every time, once its up it can be fast-efficient.
 
tough call about applying torqueedo's specs to a craft like that, once its UP it might only pull "X" amps to do 14-15 mph, its a very different kind of load, lots less drag.
-aint tryin to pick on ya Eric, I dont have a clue what its really gonna draw at different speeds once its lifted to ditch all the hull drag. they make the claim that its foils underwater resistance is "less than air", so it might approach the drain seen by electric mopeds, they can do 15-18 mph on land without a lot of current being fed.
I sure agree about the promo being misleading many ways.
25 mph for 22 miles and POOF, wouldnt be very nice!
 
again.. I dont know, if it can go 35 miles at 15 mph, I'd be pretty impressed,
but please dont ask me to try to translate volts and amps into Kwh's etc lol.
 
 
 


--- On Thu, 5/17/12, Kirk McLoren <kirkmcloren@yahoo.com> wrote:

From: Kirk McLoren <kirkmcloren@yahoo.com>
Subject: Re: [Electric Boats] hydrofoil 100 km range at 4kts (or 7.4kmh)
To: "electricboats@yahoogroups.com" <electricboats@yahoogroups.com>
Date: Thursday, May 17, 2012, 7:24 PM

 
Dont they think a buyer expecting 60 kilometers would be miffed?
Referrals are the best advertising and if they lie they wont get them.
They should go into politics if that is their attitude.
 
...  How beautiful it is to do nothing, then rest afterwards
    


From: Eric <ewdysar@yahoo.com>
To: electricboats@yahoogroups.com
Sent: Thursday, May 17, 2012 1:59 PM
Subject: Re: [Electric Boats] hydrofoil 100 km range at 4kts (or 7.4kmh)

 
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
>  
> ...  How beautiful it is to do nothing, then rest afterwards
>     
>
>
> ________________________________
> 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
>
>
>  
> http://www.gizmag.com/quadrofoil-electric-hydrofoil-watercraft/22560/?utm_source=Gizmag+Subscribers&utm_campaign=4b1188da1b-UA-2235360-4&utm_medium=email 
>  is this great or what?
> ...  How beautiful it is to do nothing, then rest afterwards
>     
>



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