Boreades
Well-Known Member
Has anyone made the conversion from diesel-powered propellor to a hybrid kit of battery-powered electric motor to turn the prop, with a smaller diesel generator to top-up the battery charge?
Electric motors for yachts?
- Thread starter Boreades
- Start date
William_H
Well-Known Member
Electric power
It would seem like a reasonable option. Obviously losses due to inefficiencies bu then diesel electric is the way to go for locomotives and V large trucks.
I understand one yacht at Royal Perth YC has electric auxiliary power. In this case using mains from the jetty to recharge batteries. The motor is used for manouvreing into and out of mooring and obviously does not have a great range under power. This apparently suits the owner where winds are predictable and long passages under power not needed.
Basicaly 650 watts equals 1 HP so for 4 horsepower which might be adequate for a small yacht this equates to something like 3000 watts of electric power. or 250 amps at 12volts. Much better is 125 amps at 24volts or even better 62 amps at 48 volts. The higher voltage means lower current for wiring, controller and motor brushes. But all the same you are going to need pretty big batteries for any sort of endurance.
You should google electric car equipment suppliers for ideas on motors.
Obviously the generator will have to have appropriate power in the engine and a suitable alternator connected. You might be able to find a large 24v alternator from a large truck or even an aircraft breakers yard.but usually 100 amps 24v is getting near to the biggest.
You may find that less than 4 HP will be adequate in flat water but really with no other answers to your query you may be in the inventing category. good luck olewill
It would seem like a reasonable option. Obviously losses due to inefficiencies bu then diesel electric is the way to go for locomotives and V large trucks.
I understand one yacht at Royal Perth YC has electric auxiliary power. In this case using mains from the jetty to recharge batteries. The motor is used for manouvreing into and out of mooring and obviously does not have a great range under power. This apparently suits the owner where winds are predictable and long passages under power not needed.
Basicaly 650 watts equals 1 HP so for 4 horsepower which might be adequate for a small yacht this equates to something like 3000 watts of electric power. or 250 amps at 12volts. Much better is 125 amps at 24volts or even better 62 amps at 48 volts. The higher voltage means lower current for wiring, controller and motor brushes. But all the same you are going to need pretty big batteries for any sort of endurance.
You should google electric car equipment suppliers for ideas on motors.
Obviously the generator will have to have appropriate power in the engine and a suitable alternator connected. You might be able to find a large 24v alternator from a large truck or even an aircraft breakers yard.but usually 100 amps 24v is getting near to the biggest.
You may find that less than 4 HP will be adequate in flat water but really with no other answers to your query you may be in the inventing category. good luck olewill
Bajansailor
Well-Known Member
There was an interesting article by Niki Perryman in Classic Boat a couple of years ago re how they re-engined their 35' Lion class sloop Siandra with an electric motor, and were well chuffed with it in comparison to the old diesel engine it replaced.
I shall see if I can find it.....
And I see that the Silette Sonic folk build saildrive legs with electric motors - have a look at http://www.sillette.co.uk/first.htm and scroll down to the bottom and open the pdf file there.
I shall see if I can find it.....
And I see that the Silette Sonic folk build saildrive legs with electric motors - have a look at http://www.sillette.co.uk/first.htm and scroll down to the bottom and open the pdf file there.
AndieMac
Well-Known Member
Nikki (Perryman) and Jamie left Fremantle (West Aust.) a few weeks ago, heading north up into Asia in their beautiful yacht. They were going to be at sea for 50 odd days (this time).
A totally inspirational couple, who I was fortunate enough to meet, whilst cruising in our area.
DownWest
Well-Known Member
There was an article in Classic Boat or Watercraft about a new build with diesel electric systems. ( I am taking hybrid to mean that the engine has a direct coupling to the prop) Worth the read as it was properly designed from scratch with the right sort of motors. IIRR, the same type of unit was used as a generator and drive motor. Brit. design made in India?
A
A
nimbusgb
Well-Known Member
I don't get it! Especially for places like the med where you might spend a lot of time motoring.
1 - You still need diesel aboard to feed the generator so you still have space and weight and general diesel engine troubles.
2 - For cruising under motor for more than a few minutes you either need
a/ a diesel engine close to the original engine capacity
b/ or a massively heavy lead acid battery bank
c/ prohibitively expensive lithium batteries
Whats the point if you do A?
Lots of power for your microwave if you do B but you end up with a diesel generator running for long periods.
No quick way to get out of trouble if you get the wrong combination of battery / generator capacity. A passing ship can pass you 25l of diesel in a jerry can but you can't charge batteries in a hurry.
1 - You still need diesel aboard to feed the generator so you still have space and weight and general diesel engine troubles.
2 - For cruising under motor for more than a few minutes you either need
a/ a diesel engine close to the original engine capacity
b/ or a massively heavy lead acid battery bank
c/ prohibitively expensive lithium batteries
Whats the point if you do A?
Lots of power for your microwave if you do B but you end up with a diesel generator running for long periods.
No quick way to get out of trouble if you get the wrong combination of battery / generator capacity. A passing ship can pass you 25l of diesel in a jerry can but you can't charge batteries in a hurry.
BabaYaga
Well-Known Member
For the electrical drive and battery side of what you're aiming at, this link could be of interest:
http://www.ozmarine.se/
I don't know if this engine option has yet been combined with a diesel generator, but I see no reason why it couldn't. Would not be cheap, though.
http://www.ozmarine.se/
I don't know if this engine option has yet been combined with a diesel generator, but I see no reason why it couldn't. Would not be cheap, though.
oldharry
Well-Known Member
Nothing new about electric power - they have been doing it on the canals for a number of years. Of course they have much easier access to power supplies for recharging the batteries. The problem as always is that batteries big enough to supply the power needed for reasonable speed and duration remain bulky, heavy, and expensive.
SIBS some years ago had a stand exhibiting a nice 16ft electric dayboat. The power plant cost IRO £5 - 6k complete with batteries , motor, and speed control gear.
Have a look at:
http://www.electric-boat-association.org.uk
http://www.thameselectric.com/
and Google for more.
SIBS some years ago had a stand exhibiting a nice 16ft electric dayboat. The power plant cost IRO £5 - 6k complete with batteries , motor, and speed control gear.
Have a look at:
http://www.electric-boat-association.org.uk
http://www.thameselectric.com/
and Google for more.
Bajansailor
Well-Known Member
Further to my note above, I couldnt find the Classic Boat that Niki's article was in (probably gave it away), but I did have a scanned copy (it was in the April 2008 issue).
Here is the scanned copy below - apologies for the poor resolution, I shouldn't have reduced it down so much. But it is just about readable if you print it out.
Where here is a link to the Thoosa electric motors website - http://www.asmomarine.com/2005/asmo_uk/01.shtml
We are in the market for a new engine for our boat, and I am starting to think seriously about perhaps getting an electric motor like what the folk on Siandra have.
Here is the scanned copy below - apologies for the poor resolution, I shouldn't have reduced it down so much. But it is just about readable if you print it out.
Where here is a link to the Thoosa electric motors website - http://www.asmomarine.com/2005/asmo_uk/01.shtml
We are in the market for a new engine for our boat, and I am starting to think seriously about perhaps getting an electric motor like what the folk on Siandra have.
nickcred
Well-Known Member
Hybrid
http://www.hybrid-marine.co.uk/index.html
Try Graham , he designed this one and manufactures it. Was at the Boat show. I know him from a business capacity and he is passionate about this field and a really genuine guy.
Nick
http://www.hybrid-marine.co.uk/index.html
Try Graham , he designed this one and manufactures it. Was at the Boat show. I know him from a business capacity and he is passionate about this field and a really genuine guy.
Nick
reeac
Well-Known Member
I,also, don't get it. The only economy gain with a hybrid vehicle comes from the fact that it can utilise regenerative braking but then some of this gain must be offset by the additional losses in the conversion processes [generator, battery, electric motor]. Obviously, regenerative braking is irrelevant to boats so you are just left with the additional losses. Maybe you could gain some electrical charge from a BIG array of solar panels but, as already pointed out, you would need a huge battery capacity to provide much propulsion.
Twister_Ken
Well-Known Member
prop spin
True there's no regenerative barking, but a prop that spins when under sail could well drive a generator. Then there's wind and solar, so the diesel genny needn't be too powerful.
True there's no regenerative barking, but a prop that spins when under sail could well drive a generator. Then there's wind and solar, so the diesel genny needn't be too powerful.
lw395
Well-Known Member
It works on canals and slow rivers because the power required is low. A 60odd foot canal barge classically requires only 1HP, one horse in fact.
For a seagoing vessel, let's say you need 10HP for an hour to get safely out of harbour and into open water where you can sail.
10HPx 1Hr is about 7400 W-Hr
at 12V that's 616 A-Hr, so with typical batteries you would want over 1000Ahr of capacity.
That's not impossible, but it's a few hundred pounds that will have a limited life.
I think the key is to have very clear ideas about what the power and duration requirements are.
If you only wanted 3.3HP for 10min to get you through Portsmouth Harbour entrance in a small boat, it becomes more like 55Ah, which is a serious proposition.
Most of us need an auxillary engine to get us back from Cherbourg when the wind dies. For a 30ft boat, even in smooth water that has to be about 10hp for 10hrs, which would imply 10,000 AHr by my crude sums, so it really does not seem possible on stored charge. So you are in the realms of serious generation on board.
Of course it is possible to be less engine dependent, I've done more engine-less cruising than most, but nowadays the logistics of work make it necessary to be able to get home!
Maybe oneday H2 fuel cells will be the storage answer, but in the meantime I think my next yacht will have a diesel engine.
For a seagoing vessel, let's say you need 10HP for an hour to get safely out of harbour and into open water where you can sail.
10HPx 1Hr is about 7400 W-Hr
at 12V that's 616 A-Hr, so with typical batteries you would want over 1000Ahr of capacity.
That's not impossible, but it's a few hundred pounds that will have a limited life.
I think the key is to have very clear ideas about what the power and duration requirements are.
If you only wanted 3.3HP for 10min to get you through Portsmouth Harbour entrance in a small boat, it becomes more like 55Ah, which is a serious proposition.
Most of us need an auxillary engine to get us back from Cherbourg when the wind dies. For a 30ft boat, even in smooth water that has to be about 10hp for 10hrs, which would imply 10,000 AHr by my crude sums, so it really does not seem possible on stored charge. So you are in the realms of serious generation on board.
Of course it is possible to be less engine dependent, I've done more engine-less cruising than most, but nowadays the logistics of work make it necessary to be able to get home!
Maybe oneday H2 fuel cells will be the storage answer, but in the meantime I think my next yacht will have a diesel engine.
johnpye
Well-Known Member
May be wrong, but I understood that part of the gain comes from running the diesel at a more efficient speed? I also understand that prop spin is at least potentially a practical source for generating power when under sail.
nimbusgb
Well-Known Member
There's a good old saying 'nothing for nothing and precious little for sixpence'.
Trailing a prop and trying to generate a couple of amps in a conventional setup ( shaft alternator ) is pretty difficult. With an electric motor things may be a bit more efficient but you are never going to put back anything near what you take out.
for an 11.5 m boat I need a 13kw motor to cruise at 5 kts. At 72 volts thats 180 amps. If I am sailing at 5 kts and say dragging enough to generate 1 kw ( unlikely but I'll go with it ) thats 13 amps. It will take about 20 hours to put back 1 hours motoring into the battery bank.
Ok for a long distance cruiser but as a day-to-day cruiser in the med where one can spend 5 hours motoring in a day quite easily its a non starter.
So you start to look at hybrid solutions. A fairly small battery bank (say 6 110 ah batteries ) for 72v. Gives you about 20 minutes full taps before the batteries are totally drained ( 180 amps at 72v ) . Install a 15kw diesel genset so that you can still cruise at 5 kt. Now you have a 15kw genset, 6 BIG batteries and all the other stuff as well some of which are chargers, inverters and water sensitive gubbins. One advantage is that you can get rid of the gas installation and just run a 220v ac stove, oven and micrwave with that genset available.
6 batteries ( 150kg ) and the genset ( 200kg? ) and the electric motor assembly ( 34kg) makes my smelly old perkins a good deal lighter.
The thought of having a 220v generator capable of putting out around 100 amps and DC wiring at twice that on a boat scares me!
Don't get me wrong I love the thought of an electric drive but it just doesn't seem to be there yet!
Trailing a prop and trying to generate a couple of amps in a conventional setup ( shaft alternator ) is pretty difficult. With an electric motor things may be a bit more efficient but you are never going to put back anything near what you take out.
for an 11.5 m boat I need a 13kw motor to cruise at 5 kts. At 72 volts thats 180 amps. If I am sailing at 5 kts and say dragging enough to generate 1 kw ( unlikely but I'll go with it ) thats 13 amps. It will take about 20 hours to put back 1 hours motoring into the battery bank.
Ok for a long distance cruiser but as a day-to-day cruiser in the med where one can spend 5 hours motoring in a day quite easily its a non starter.
So you start to look at hybrid solutions. A fairly small battery bank (say 6 110 ah batteries ) for 72v. Gives you about 20 minutes full taps before the batteries are totally drained ( 180 amps at 72v ) . Install a 15kw diesel genset so that you can still cruise at 5 kt. Now you have a 15kw genset, 6 BIG batteries and all the other stuff as well some of which are chargers, inverters and water sensitive gubbins. One advantage is that you can get rid of the gas installation and just run a 220v ac stove, oven and micrwave with that genset available.
6 batteries ( 150kg ) and the genset ( 200kg? ) and the electric motor assembly ( 34kg) makes my smelly old perkins a good deal lighter.
The thought of having a 220v generator capable of putting out around 100 amps and DC wiring at twice that on a boat scares me!
Don't get me wrong I love the thought of an electric drive but it just doesn't seem to be there yet!
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planteater
Well-Known Member
True for bigger boats and longer passages. For dayboats and weekenders who mostly use the motor to clear/regain moorings the annual servicing cost of a diesel (or even an outboard) is disproportionate to the amount of use they receive.
Electric motors could be made pretty much maintenance free. Simply drop it in for reconditioning every 5 years or so.
srm
Well-Known Member
Suggest a Google search for 'electric yacht propulsion' there's lots of info out there. There are arguments for diesel electric being more efficient and economical.
Seem to remember reading Laguna and Broadblue cats both producing diesel electric versions. Also, there were articles in YM two or three years back (before I stopped buying it anyway) by Nigel Calder or someone with similar authority on his new boat's systems including diesel electric.
As mentioned by others stored power has limited range unless lots of wind turbine / solar power input. Although, I remember reading about a US design using stored plus regenerative charging while sailing to give a totally wind powered vessel.
Its two or three years since I looked into this, so there is probably even more info out there.
Unfortunately, non of us has actually answered the original post with actual experience.
gordmac
Well-Known Member
Why do you want to do this? If it is to try and save money forget it. If you are prepared to spend a lot of money to save an insignificant amount of pollution it may be possible.
You need to add a lot of weight and do away with a lot of space to add a pile of batteries and a large electric motor (and a genset). You may need a cooling system for the motor, I don't know how much waste heat they produce. You need to generate as much electricity as you can by eg solar, and wind. Rotating prop may be usable. Don't forget that things like a rotating prop will generate power from boat motion and will slow it down. You may then get away with a small genset, are normal commercially available ones efficient? Additionally all the extra kit has an environmental consequence in making and disposing of them.
Hybrid cars tend to be petrol rather than diesel.
As a design engineer I think this could be an interesting project, pointless but interesting!
You need to add a lot of weight and do away with a lot of space to add a pile of batteries and a large electric motor (and a genset). You may need a cooling system for the motor, I don't know how much waste heat they produce. You need to generate as much electricity as you can by eg solar, and wind. Rotating prop may be usable. Don't forget that things like a rotating prop will generate power from boat motion and will slow it down. You may then get away with a small genset, are normal commercially available ones efficient? Additionally all the extra kit has an environmental consequence in making and disposing of them.
Hybrid cars tend to be petrol rather than diesel.
As a design engineer I think this could be an interesting project, pointless but interesting!
jason -and the arguenauts
Well-Known Member
Why bother? Before diesels came along, sailors sailed everywhere which is why they were called - sailors!.
Best thing to do is to junk the old tub and all the excess weight it carries and get yourself the sort of boat that really does sail like a witch. Build the whole lot in wood and you would really be eco friendly.
Whats more my guess is that you'd have a lot more fun.
Best thing to do is to junk the old tub and all the excess weight it carries and get yourself the sort of boat that really does sail like a witch. Build the whole lot in wood and you would really be eco friendly.
Whats more my guess is that you'd have a lot more fun.
reeac
Well-Known Member
In the interests of brevity I didn't mention this one but if you look at specific fuel consumption curves for marine diesels they're pretty flat around the speed range of 1500-2400 rpm [the bigger engines are best at the lower end of this range] which is the speed that people generally use except in extreme conditions so in practice I don't think that there's a lot to be gained there.
The real point of diesel-electric set ups is that they give a very convenient way to link a running engine to a big stationary load in order to get it moving e.g railway trains.
