Electric propulsion

[kingfisher]

Last year VETUS put a standard electrical propulsion system on the market. Check it out:

http://www.vetus.nl/producten/mainns.asp?productid=92&lang=2

Apart from the obvious environmental issues:

PRO
No gearbox
Delivers about 5hp I believe
Less stress on the boat
Takes up less space

AGAINST
The trouble with electric drives is the range, of course. But for the serious sailor, consider this: electric propulsion, coupled to a generator (which you need anyway). Best or worst of both worlds

Can I do the maintenance ? And before any of you get started on self-reliance: I can repair some basic engine-problems, but don't ask me to go further than the rocker box. And I believe I'm part of the majority of the boating community.

Frequent replacement of batteries. I have to buy spares for the diesel as well.

CONCLUSION
I for one am seriously considering it for the next reengineing job.

Obi-Wan

 

[chippie]

An interesting concept at least. In my opinion the reduction in complexity achieved by removing the gearbox is probably offset by the introduction of a system that is very sensitive to the marine environment.(All things electrical.)
Do trains still use diesel electric technology? The rail companies must have done a cost effectiveness audit and it presumably stacked up for them.
Five horsepower seems like far too little for the hassle involved in fitting it. I suppose an electric motor from one of the larger bowthrusters could fit the bill but whether it would be price competitive is another matter.
Upon rereading this post I think I sound unduly negative, sorry but its just my natural conservatism towards anything unproven.
I will certainly follow this thread with interest and will definitely look at the Vetus site you reccommend.

 

[steve_cronin]

I suspect that you may live to regret it....

EFFICIENCY is the key.

Now if you put the environmental factor at a premium this may not be valid but even such a position is flawed because of efficiency and the fact that you are meerly moving the polution from one place to another.

The determining the efficiency of a generator/battery/electric motor set up involves many factors.

The generator consists of an internal combustion engine which drives an alternator. Substantial losses here AND you need to carry a lot of fuel for the genny, just as much or even more - because of inefficiency - than your existing engine requires (unless you take a large cut in power) The typical genset only puts out 80% at best of the energy in the fuel down the output cables. Then you are going to convert this to chemical energy in the lead acid batteries (of which you are going to need an awful lot)- again another loss of efficiency in the production of free hydrogen - itself a hazard. This is going to be stored until you use it - again there will be a leakage of around 5% over the span between periods of boat usage. When you use it there will also be losses in the switchgear/control system as well as in the motor itself. I don't think that it is feasible in a yacht. Now the diesel electric locomotive uses the diesel generator/motor configuration to utilise the fact that electric motors have a very flat torque curve, developing maximum torque at zero rpm. In DE locos the diesel genset is set running at a constant and pre-determined optimum efficiency speed and provides current directly to the electric motor(s) without storage in batteries.
So why not remove all the gubbins between your genn y's liquid fuel engine and connect it straight to your saildrive - much more efficient! But wait a minute, thats what you have already!

As to the loss of a gearbox, well the Vetus drive DOES have one. It runs through a sail drive after all.

In some places (like Rutland Water) there is a complete ban on internal combustion engines because of waterborne pollution going into drinking water. In this case some people use electric propulsion out of necessity but this is from batteries brought onboard from home based charging facilities. So in effect, to keep Rutland Water clear, the back yards of Leicestershire are full of smoke from gennys or the residents of Lockington will see even bigger plumes of steam from the cooling towers!

Steve Cronin

 

[Twister_Ken]

Got a generator anyway

Not sure the diesel electric idea makes much sense on smaller boats and/or in an 'ongoing coastal cruising scenario' where the engine is used often enough to keep batteries full. But for an offshore cruiser, where in all probability there is a battery recharge problem which results in a generator being fitted AS WELL AS a standard donkey, it would seem to be good way to kill two birds, and probably save weight and complexity at the same time.

Especially true for dedicated rag'n'string guys who don't want to power along at 8 knots when the wind fails, but would like a propellor for inshore manouevering.

 

[pvb]

I've been looking at the implications of electric propulsion, Henk, and I don't think a battery-based solution will be suitable for your Sirocco if you want to have a reasonable operating range.

You're aware of Solomon Technologies, but have you seen the Fischer solution (www.whisperprop.com) or the Lynch Motor site (www.lynchmotor.com)? Also, I've found the links at www.econogics.com/ev/evboats.htm are useful sources of info.

 

[simonjinks]

Silette Sonic

Take a look at the Sonic drive from Silette Sonic, it was in YM's new gear after the Soton Boat Show. They have fitted a lot of these units, the advantage to my way of thinking is that the generator (that you really need for a cruising yacht) can be placed anywhere in the boat, maybe to better stability, trim or noise levels. Coupled to a Stirling engined Whispergen unit, it could provide near silent running with better overall results. More expensive though, i think.

 

[hugh_nightingale]

Well, I think I may have missed the point here and I have not yet read the Vetus site but I rather thought the idea was to use the battery/motor/prop in reverse as a prop/generator/battery charge system.

Perhaps I read too much into it and this was not meant but a towed or wind generator is surely the answer.

 

[Twister_Ken]

Re: Silette Sonic

More expensive than a diesel donkey AND a generator?

 

[Guest]

Also started atread on the other bard about the Solomns electric engine (electric wheels) it seem like this is becoming of interest. If the makers are to believed (which I don't without proof!) I can go from a 25hp diesel to a 5KW geny/motor combo and reduce fuel use by 4/5 which seems to suggest that the ergenomics work. Also the Solomns is the only one I have so far found that regenerates power and its enought for all requirments underway which is a big attraction although their is drag to think of (energy must come from somewhere) The piont about battery size is that you can carry enough for the 30min run out of harbour without having to warm up the desil rather than looking for long range. Looks promising but still looking.

Roly, Voya Con Dios, Glasson, Lancaster

 

[Guest]

Kingfisher said:
PRO
No gearbox
Delivers about 5hp I believe
Less stress on the boat
Takes up less space
AGAINST
The trouble with electric drives is the range, of course. But for the serious sailor, consider this: electric propulsion, coupled to a generator (which you need anyway). Best or worst of both worlds

Also, compare smell and vibration? Heat and noise? What are the chances of getting "dirty electricity" vs dirty fuel. Instant on, or warmup?

"serious SAILOR" ? How much motoring around are we talking about here? If you mean just motoring in/out of the Club/marina, electrics should be fine. With the wind up, you can re-generate under sail (prop spins and turns motor into generator)... you can arrive home with more stored energy than when you left.

Like any technology, the right application is key. Electric motors and batteries and charging systems, etc continue to improve, but they're not "there" yet for the sorta cruiser that wants to power their aircon, hair driers, colour TV's etc... Unless you want to carry a small genset, in which case all this stuff is possible too.

Can I do the maintenance ?

what maintenance? <smile>

Frequent replacement of batteries

David Tether (Solomon Technologies - the "Electric Wheel") reported just the other day:
"We have AGM that have been routinely charge and discharged to 40% hundreds of times with no degradation in performance at all. "

Solomon uses Lifeline batteries...

I've been trying to educate myself on this electric propulsion thingee. My particular interest is in a 40-persons private ferryboat for Toronto harbour (Canada, eh?)

I've been gathering together the scraps of my "research" as a web site at:

http://groups.yahoo.com/group/QCYCTender/

I'm a freshwater sailor, and what I see happening around me are speed limits, no wake zones, no hydrocarbons laws, etc. (like it or not). All bodes well for electric, I believe.

Cheers

Lock

 

[Paulka]

Beware of electric power out of batteries.

The environmental argument is a fallacious one.
To drive any sort of boat out of battery energy, you will need literally enormous batteries, which will become an environmental nightmare in case of an accident, or more pragmatically, whenever they have to be replaced.

No this is no theory!

There is here, in Spain, near Barcelona, a small lake, which is protected by stringent regulation. As the lake is a popular touristic attraction, there are a number of boats taking the tourists for a sightseeing. A consequence of the regulation is that all the boats are electricity (battery) powered. Two years ago, one of those boats sank. The authorities organized an urgent, heavy, and extremly costly operation of recuperation of the boat's batteries, as those were rightly considered a vital threat for the lakes fauna and flora.

The power out of a generator is an illusion as well, as allready mentionned in a former post.

The fuel efficiency of any diesel engine is around 40%, at best.
The efficiency of any generator or electric motor is 80 - 85% at best.
Thus, 70% (.8 x .85) for a generator - electric motor.
The efficiency of the battery again, around 80%.
Thus, 55% (.8 x .85 x .8) for an ensemble generator - battery - electric motor.
What does this means?
It means that a little over half the energy out of the diesel will reach the propeller!
Connecting the propeller directly to the diesel, via a gearbox, will get 95% of the energy to the propeller.
This means as well that you'll have to burn nearly twice as much fuel to provide the propeller with the same energy. Of course, producing twice as much CO2, fumes etc.

Under this conditions, any claim of environmental protection is at best the result of ignorance, at worst, a deliberate lie.

.... Nevertheless, I have an electric outboard to go from my moored yacht to the landing place! ..... with a 45Ah battery giving my dinghy 20 - 30 minutes autonomy.

;-)

 

[Guest]

Paulka:
Beware of electric power out of batteries.
The environmental argument is a fallacious one.
To drive any sort of boat out of battery energy, you will need literally enormous batteries

Ummmmm... that'd depend on how much energy you wish to shore, no? ie what you need, before you can recharge?

Paulka:
which will become an environmental nightmare in case of an accident, or more pragmatically, whenever they have to be replaced.

Even sealed AGM batteries? Wouldn't these be better on the bottom than a tank(s) of diesel or gas?

David Tether (Solomon Technologies - the "Electric Wheel") wrote the other day that they have "cycled" AGM batteries hundreds of times to *only 40% depth of discharge maximum* ... and that they see no discernable drop in capacity. Seems the trick is, to NOT cycle to 50% or more DoD.

And these AGM's are still pretty much just yer average lead/acid technology... about the most recycled material on the planet.

No this is no theory!
There is here, in Spain, near Barcelona, a small lake, which is protected by stringent regulation. As the lake is a popular touristic attraction, there are a number of boats taking the tourists for a sightseeing. A consequence of the regulation is that all the boats are electricity (battery) powered. Two years ago, one of those boats sank. The authorities organized an urgent, heavy, and extremly costly operation of recuperation of the boat's batteries, as those were rightly considered a vital threat for the lakes fauna and flora.

Guess these weren't sealed batteries. Would have thought the acid would dilute pretty much, and the lead? not water soluble? still seems like the lesser of the two evils <vs diesel/gas)

.... Nevertheless, I have an electric outboard to go from my moored yacht to the landing place! ..... with a 45Ah battery giving my dinghy 20 - 30 minutes autonomy.
;-)

Good man! ... and, there you go. Like any technology, it's just a matter of using it in the right application. My own personal little project is a 40-person private ferryboat that needs to make 20 or less trips a day, 2 miles round trip, and can recharge 1/2hr between trips and 8hrs overnight. Shorepower, solar and wind, and eventually, fuel cells. No fossil fuels on the boat.

Lock

 

[Twister_Ken]

Electric noise

A friend has (had?) and electric launch on the Thames (a Frolic 21). While the noise is totally different from the explosive rumble of a small diesel the speed related whine that comes from the motor and shaft is quite intrusive. Silent it is not - rather 'milk floatish' in fact.

 

[Guest]

Re: Electric noise

"Twister Ken":
A friend has (had?) and electric launch on the Thames (a Frolic 21). While the noise is totally different from the explosive rumble of a small diesel the speed related whine that comes from the motor and shaft is quite intrusive. Silent it is not - rather 'milk floatish' in fact.

Sorry - don't understand "milk floatish" Ken (I'm from the colonies, eh? <smile>)

But this is interesting, about the different noise. Wonder which motor was involved, whether it had motor mounts/ vibration dampeners,was the engine compartment "sound leak-proofed" or otherwise soundproofed, and whether the sounds of the shaft/prop are always there, but just more noticable, with the diesel sounds absent!

Lock

 

[Trevethan]

Re: Electric noise

a milk float is an electrically powered truck used to deliver milk to your house of a morning.. Course the're aren't many about these days now thgat everyone gets their milk from the supermarket

 

[Paulka]

Lock
Would have thought the acid would dilute pretty much, and the lead? not water soluble? still seems like the lesser of the two evils <vs diesel/gas)

Sure, acide will dilute pretty much ...... of the fauna and flora. :-(
No chance to take it out of the water.
Diesel as well as gazoline don't mix with water, will come on the surface, where it can be collected.
It's a mess, agreed, but feasible without extraordinary measures, and the remaining, if any will oxydate, or be eaten by some bacterias.

This being said, I agree that for the case you describe, electric propulsion is reasonnable. .... Even if it doesn't eliminate the pollution, rather desplace it to the power plant.

Good luck.

Paul

 

[Twister_Ken]

Re: Electric noise

Some details at http://www.creative-marine.co.uk/Frolic 31.htm

 

[Paulka]

.... And I forgot this

Yes, the composites of lead, like the composites of any heavy metal are toxic, some of them heavily, like cooper sulphate used as insecticid!
One of those composites : lead sulphate (PbS) is the most important part of the chemistry of the batteries, and is probably free in the electrolyte (the battery's liquid).

More bad news?

Yes, lead disolves itself in water.
Very slowly, and in very small quantities, but enough to provoke saturnism.
It's the reason behind the ban of lead pipes, which were very common as water pipes in the houses, till the middle of the 20th. century.

Definitely, the lesser evil is oil, at least in this case!

Sorry for the contradiction.

Paul

 

[Trevethan]

Re: .... And I forgot this

But in the case of lead piping, we are talking small amounts of water being exposed to vast amounts of lead for extended periods of time.

Because the water would sit in pipes overnight it would pick up lead. run that water out and the amount of Pb would be far far less.

Regarding acid. Harmful in higher concentrations, but given the amount of acid in a battery compared to the amount of water in the sea or a typical navigable river, it would take an awful lot of acid dumping to have a detrimental effect. acid spills in the bottom of the boat could be easily neutralised with baking soda or similar albeit cautiously to avoid the hazard of a hydrogen gas build up.

Lead is also the most recycled metal on the planet. In the US 95% of lead in batteries is recycled. and about 80% of all lead is recycled. The majority of lead goes to battery production. Other uses in the US include lead ammunition and chemical production which are difficult to recycle..

In the UK a fair amount is used in construction. Again this is recycled.

Lead has a very bad press, and yes while it is toxic, it is far more benign than say cadmium and as I already stated is very recyclable as are other battery components including the acid and the plastic casings.

Acid is either cleaned up and re-used or neutralised and used in chemical production. The plastic is re-used for new battery cases etc.

If you run solar panels and a regeneration system (if under sail) you dramatically reduce your fossil fuel consumption.

Also if you do make use of a hybrid genny-battery system, you can usually make do with a smaller fossil fuel engine that can run at a constant efficient speed to maximise efficiency and reduce emissions.

There is a long thread about the electric wheel marine propulsion system on another channel.. PBO I think.