SUGGESTIONS SOLICITED. Pasted below is my exploration about using a Torqeedo electric outboard as auxiliary power. Bob linked me to his "Hindsight" post and suggested I write him here as the issue was a bit off topic of the Bolger group. I am new to this group and have only read this one post and responses. I will appreciate any suggestions and links members provide me with.
ROGUE is an 8,000 lbs, keel-less, 26'x7.5'x1'draft sailboat, and very close to maximum trailerable weight, so weight matters. The designed outboard mounted inboard as a quick and dirty "saildrive" will not work in the shallow, pointy stern. Neither will any other inboard arrangement. The rudder is considerably deeper than the hull and kicks up. It would be ideal to mount a motor deep underwater on the rudder with a feathering prop or a fixed prop turning just fast enough to prevent drag (If it could generate electricity while dragging through the water, better still). A gas outboard cannot be reasonably mounted (up out of the water) to the rudder. A Torqeedo could be and is therefore a desirable solution.
Bob,
This is my second attempt to post. Perhaps I didn't click send.
The Atomic 4 is rated at 30 HP. What HP and voltage motor did you replace it with? Did you join the motor to a slower turning larger diameter prop for greater efficiency? I assume that your Trogan batteries are golf cart batteries and that eight would total 48v. What amperage batteries? How long do they propel your boat at at various speeds? How does your electric drive compare with the Atomic 4 especially regards punching into wind and waves? Will the Honda generator continuously propel your boat so long as there is gas in the tank?
Prior post to Bolger group. Are my figures reasonable? Is there some way of wringing cost out of the charging system or batteries (lower amp and run time, more reliance on gas generator for instance)?
Cost of Torqeedo: $3300 for the 24v cruise 2.0 remote plus two 12v 210 amp AGM batteries at $400 each, or $3800 for the Torqeedo recommended 48v cruise 4.0 remote plus four 12v batteries at $400 each. A best, run time at hull speed would be approx 2 hours, approximately 12 nautical miles for the 4.0. ROGUE is not a marina boat so a generator is needed: $1000 - $1200 for quiet Yamaha or Honda. It is also needed for extended run time. Solar chargers are about the same cost but do not allow extended run time. $150 or more for charger ($850 to $1000 for 48v). So going with what Torqeedo recommended for ROGUE: $3800 + 1600 + $1000 + $1000 for charger/inverter (need inverter anyway so $500 for choice of electric outboard and getting a more expensive inverter/charger). Total for Torqeedo recommended 4.0: $6900 Nearly half the material cost for building ROGUE.
vs
Tohatsu 9.8 hp Four-Stroke with gas tank, remote control, electric start and alternator: less than $3000.
Eric
--- In electricboats@yahoogroups.com, loosemoosefilmworks <no_reply@...> wrote:
>
> Electric propulsion with six years of hindsight...
>
> I'm just about to get around to taking out my Home brew Mark 2
> Electric drive in preparation to installing a new one and it has made
> me think a lot about various electric propulsion subjects. Hindsight
> is great that way.
>
> Of course you can't really talk about the Mark 2 without touching on
> the Mark 1 system which was your basic Etek motor and a golf cart
> controller a beast that was prone to serious over heating as none of
> us seemed to get the big difference between electric propulsion for
> boats and electric propulsion for land vehicles and the different
> usage they entail. Throw in the fact that sailboat needs are quite
> different than power boat needs as well...Not really surprising that
> the mark one system was something of a steep learning curve and a
> sometimes pain in the butt.
>
> That said it worked out pretty well...
>
> The Mark 2 system was not too different but I did switch to an
> Advanced Electric motor which made all the difference...Over heating
> was a thing of the past and while I did do a lot of tinkering with
> props and gear ratio it pretty much worked all the time and other than
> my own "tweaking" was a no maintenance no repair kind of thing...It
> worked from day one and is still working.
>
> So why am I ripping it out and replacing it with an Electric yacht
> drop in?
>
> Part of the reason is that I am going to be doing a lot more long
> distance cruising in the near future and a regen capable system
> seemed like a good thing. Electric yacht makes a good unit and their
> controller is first rate. Plus it is a simple solution and of all the
> electric drive systems I have come across it is the one that seems to
> have both feet on the ground and gets just what a Auxiliary propulsion
> system for a sailboat needs to be. Throw in the fact that they also
> have some very clever things in the pipe line... Bottom line is that
> any system I'd design for myself would just be a clone of sorts so
> why reinvent the wheel?
>
> So what have I learned having had electric propulsion for going on six
> years?
>
> One...It is seriously cheaper to upkeep than a internal combustion
> system. when I pulled my Atomic Four a friend also pulled his and
> replace it with a Diesel so we have something of a control group as he
> is a seriously anal retentive guy and keeps track of every cent he
> spends and the two systems work out like this...
>
> I spent $890 for the initial electric drive a year later I replaced
> the Etek with an Advanced Electric which was about $500 but was able
> to use the old controller. I switched to chain drive and bought a
> bunch of sprockets allowing me to experiment with different gear
> ratios which cost an astounding $30 from Surplus center. Other than
> grease for bearing that was it...Not a whole lot out of pocket.
>
> My friend who installed a new Yanmar on the other hand spent around
> $4000 ( he got a great deal) on his engine plus another $2000 give or
> take on installation.in the five years since he has racked up a total
> of $6000 ( just over in fact) in parts,oil changes,filters and
> suchlike. Like me he does all his work himself so this is simply parts
> and does not include labor or personal work time. His diesel usage
> averaged thirty gallons a year.
>
> In the six year I just recently replaced my battery bank..My first
> bank cost $400 ( Trojan clones I bought in Puerto Rico) which were
> still holding up but I decided to replace them as six years was
> pushing it a bit and I got a deal on real Trojans for $100 a
> piece...So the new bank cost $800. Throw in gas for my Honda 2000
> generator based on time spent charging the propulsion bank which adds
> eighty hours of generator time over the last five years which comes to
> 257 hours which equaled $342 for gas or $5.70 a month.
>
> My friend with the Yanmar and I both sail and do not do long passages
> under power. Propulsion systems are just used for auxiliary use of
> getting in and out of tight places the odd bit of powering in no wind
> situations and suchlike. In the six years I have logged about 9000
> miles of sailing while my friend has logged right around 7000 miles.
> As it happens the Yanmar is in need of a complete rebuild but will
> most likely be replaced with another Yanmar as the rebuild costs come
> pretty close to simply replacing the engine. The engine was well
> maintained.
>
> I'm sure conclusions can be drawn from all this...Though I'm not going to.
>
> What I am going to mention though is that I hear a lot from armchair
> experts about how electric does not work...I hear a lot about how
> batteries don't hold enough power to make it work and suchlike. I hear
> a lot about how we all have to wait for some techie advance that will
> all make it possible. I hear even more from people who are convinced
> about electric propulsion but still spend far too much time arguing
> battery technology and perfect hull forms instead of just doing it (
> to steal a phrase from Nike) and getting on the water. The perfect
> test bed is putting an electric motor in a boat and using it!
>
> All the best
>
> Bob
> http://boatbits.blogspot.com/
>
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