Sailboat powered like submarine

Hi.

I know, people here are exasperated with newbies dropping by all giddy about electric propulsion on a sailboat, but please, bear with this newbie for a couple of minutes.

What do people around here think about electric propulsion as an add-on to an existing diesel engine? Basically the motor is connected to the existing propeller shaft and a clutch is installed at the coupling of the shaft to the diesel engine. So, in short it's kinda like a WW2 submarine: When the diesel is running with the transmission engaged, it's also turning the electric motor and recharging the batteries, but when under silent running, the diesel is off and decoupled from the shaft, so no power is wasted in the diesel's transmission.

The advantage of such a system (as I see it) is that there is no dependence on the electric drive - one can always switch back to diesel. As a result, the battery bank can be kept smaller, just enough for running the drive for a couple of hours. The smaller bank is also easier to recharge.
At the same time, all the standard electric features are still available if they are wanted: regenerative charging, silent running, electric sail, coolness factor, etc.

The disadvantage, of course, is that there is no economy when diesel is used. It actually will be slightly less economical coz the electric motor introduces additional losses, even when not charging.

Now, the "raison d'etre" for such a system: My personal sailing habits usually involve getting out over the weekend and motoring, in total, maybe 2-3 hours tops. A typical electric drive (if not pushed too hard) can handle such runs no problem, and then the charge can be replenished by solar power through the rest of the week (sun is strong here).

On the other hand, on the occasional longer trips the engine sometimes runs for 6 hours a day for several days - it's a narrow river here, so there is sometimes no choice - so obviously an electric drive won't do if one actually wants to get anywhere before the winter arrives. So, in this case one would run on diesel only.

So, any comments? Also, before apex1 starts calling me names: I'm not a green nut, and I fully realize the downsides of electric drives. I simply want to see if such a setup can make any sense in my weekend sail pattern.

Thanks.

 

As much as I've ranted against "hybrid" drives this is the only real application I can see for it.
Kudos for being realistic in your range and expectations for your small vessel,although you will get zero regenerative charging-unless you're moored on a river.


If it makes sense to you,go for it.
IF diesel electric worked for larger vessels and had a decent payback time-I'd go for it myself.
But it doesn't,and I haven't.


Something like this:
http://www.frenchmarine.com/product/Vetus-Electric-Drive-EP2200-237-21

 

This makes good sense to me.

-Tom

 

That makes sense. This hybrid system is actually offered by VETUS (VETUS - ECO) and it runs pretty much like you posted.
The brush-less electric motor is fitted to a diesel propulsion acting as a dynamo and charging batteries when its not in use. You then get to use the electrical engine till batteries run out.
Rinse and repeat

So yah subs did it more than 70 years ago and it worked

 

Actually there are a whole lot that still do....

 

Well... Modern subs don't do it anymore - the diesel and the electric motor are not on the same shaft. And the most modern ones also have various exotic propulsion methods: Stirling engines, fuel cells, etc.

 

Apart from your bold and insulting comment, I agree with your thoughts.

Of course there are drawbacks, but you obviously can bear with them, and are willing to leave a cost/efficiency calculation out of the equation.
Therefore this setup makes sense for you.

And before you start to defend your offense, try to improve your manners, it is not wise for a new member to comment on any others way to contribute without knowing them for a while.

Regards
Richard

 

From an efficiency point of view I see no advantage and considerable convolution, complexity and contrivance. Unless you were in areas that forced you to go electric, no need for such a system.

The reason you see resistance to electric systems, isn't because we thing they all suck. In reality, most would love the idea of noiseless propulsion, but then the reality of electric kicks in and we go back to bitching about our internal combustion contraptions. Range to a large degree and weight are the biggest issues as you might imagine and until we solve these two issues, electric will remain the redheaded step child status it deserves.

 

I have seen some amazing new electrical cars and bikes discovery channel with very impressive speeds, torque and stamina.
Seems the marine field is lagging a lot in that area as most electrical innovations are in other fields ...
Ive seen no less than 8-9 new electrical innovations in cars, but not one in boats (from my limited experience that is)

One of them was a sports car that outraced, out ran and out ranged a very popular sports car. A prototype but sure looked good.

 

Not really Vulkin.

Just cars are not boats.
We handled that issue quite a few hundred times now with always similar results.

When you count it all, in a fair comparison, 99% of the boaters would have no benefit, and allways, with no exemption, it is far more costly than a common IC setup.

On ocean crossing boats it is still not possible to go hybrid at present.

(well, I have to edit that)
yes, when you pay for a aircraft carrier with the accommodation of a cuddy cabin, it can be done.
But then again, "sensible" is a term Hybrid lovers don´t like.

For the given application here, and in the light that it has not to be "sensible" by all means, it is a possible way, no doubt.

Regards
Richard

 

Makes sense ... i guess its a matter of finding a way rather than if its sensible or cost effective.
So on a day to day use its not practical but its possible as a concept.

Thinking about it what would a hybrid hold as a advantage?
I mean subs HAD to do it since they cant get the air while submerged.
But what would you gain ?
Its an interesting topic, ill go dig the other posts Apex referred to, now i am interested

 

Actually, while not modern the type 633 or Romeo class subs have basically the same propulsion system in place as mentioned here products of 1960s Soviet Russia, they are still used by North Korea, Egypt, Bulgaria and Myanmar. I also believe the Chinese use them as training platforms but I'm not sure..either way there still used-ish. The German type 212 is an interesting example of an "exotic" system and is exceptionally quite.....and sorry for the pseudo-hijack .....

 

When I was looking into all this and was being touted as being the future etc etc etc I met up with a fellow who built his own parallel sailboat unit.
He was a retired Boeing engineer,so he had the background plus his old workmates to rely on for advice.



It did what he wanted,he could have silent motoring for fishing in his small sailboat.
I don't know if fish are startled by motors and won't bite,or if his technique was good but he seemed to have better results fishing than others.

But when trying to regen. recharge at any sort of rate he'd drop from 6 knots sailing down to 4.

 

Apex wrote "...and always, with no exemption, it is far more costly than a common IC setup." Is it? At what cost do we burn hydro-carbons? I look forward to the day we look back and think, "What dinosaurs we were to waste hydro-carbons by burning them."

For the record Richard, I like and respect you, but your manner can be quite harsh at times. Perhaps it's an English issue, perhaps not but the original poster is entittled to his or her opinion (of you and the impression you've made). No?

exttra,

I think it would be a matter of balancing the components to your needs and desires. Diesel size, electric motor size, prop size, battery size, etc. Remember, your battery capacity is really only half of what it's rated at and even less if you want them to last longer. The more shallow you drain them the more cycles they will endure. Again, balance.

You may be interested in the endless sphere website (Note: a vessel is considered a "vehicle"). Check out Jeremy Harris here through the members list (in the header).

-Tom

 

It is.

Neither do the el motors nor the batteries come in for "free". The environmental footprint for a 10kW el. setup is far higher, than the 10kW IC would cause.

My sharp comments may not please anyone, and are not thought to.
When candy sweet hypocrisy is the expected response, one should probably not ask for experts advice or even opinions!

Regards
Richard