Electric Propulsion (Podmaster?)

[Dave_Seager]

Eco?

...maybe the hybrid would be a good choice to satisfy my eco desires!

I must question your eco logic. Electricity is only as green as the generator used to produce it. Hybrid systems can only be greener than direct drive from the generating engine by virtue of lower fuel consumption. Sometimes this is achievable but usually because it allows the engine to be run at constant speed for maximum efficiency. Cars also use regenerative braking. Boats run at near constant speed anyway and have no brakes so there is little chance of improving efficiency from a hybrid set up.

 

[maxi77]

I must question your eco logic. Electricity is only as green as the generator used to produce it. Hybrid systems can only be greener than direct drive from the generating engine by virtue of lower fuel consumption. Sometimes this is achievable but usually because it allows the engine to be run at constant speed for maximum efficiency. Cars also use regenerative braking. Boats run at near constant speed anyway and have no brakes so there is little chance of improving efficiency from a hybrid set up.

I agree, a hybrid will not really improve the green credentials of a boat, though if the battery pack is big enough then the day to day power needs can be drawn from the battery charged from shore power and you only need the hybrid power pack when conditions indicate the need for longer high power running.

 

[pvb]

I agree, a hybrid will not really improve the green credentials of a boat, though if the battery pack is big enough then the day to day power needs can be drawn from the battery charged from shore power and you only need the hybrid power pack when conditions indicate the need for longer high power running.

But when you consider the generation of the shorepower electricity, the losses in transmission, the losses in the charger, the losses in the batteries, and the losses in turning the stored electricity into propulsion, just how "green" is it??

 

[Tranona]

Hi,

Have just bought a new (to me) 30ft sailing yacht which needs a new engine. I was wanting to go down the 100% electric route instead of replacing the current one with another diesel. Has anyone replaced theirs or have any experience of electric 'engines' on yachts?
I noticed the Podmaster in this months PBO but can't find a dealer in the UK with any more info regarding how to buy, cost etc

Cheers

Electric propulsion is well developed for boating use. Many small boats used on inland waterways use it. That is because the conditions of use lend themselves to that method. Low power output requirements, low speeds, short duration, convenient charging points and space for power storage..

None of these conditions apply to a sailing boat auxilliary, which is why, for all the effort and money thrown at it nobody has come up with a viable system. While there are technical drive solutions available at a cost, nobody has produced a viable power supply that is cheap simple, low cost and small in space requirements. The bulk of the power unit is very little different from a diesel engine, but the latter only requires a small space for its fuel to give it a usable range.

As already mentioned using electricity for propulsion on a boat is not "evironmentally friendly" unless you can find a way of generating power without any impact on the environment.

While there is a lot to be said for hybrids as overall they can be more efficient in turning the power into useful propulsion, the cost, weight, space and complexity make them impractical as small saiboat auxilliaries.

The fuel usage (and therefore environmental impact) of a 30' sailboat is minimal. Average usage is typically 100 hours a year and a 20hp engine will burn about 1.5l an hour - 150l a year or the equivalent of driving 1500 miles in a typical small diesel car.

So, until somebody comes up with way of storing, say 20 hours worth of electricity in a space equivalent to 30 litres of diesel and a mechanism for replenishing it easily, cleanly and cheaply, there is nothing to touch a small diesel for the job.

 

[Stemar]

Most boats spend most of their time sitting, waiting for someone to sail them. Good solar panels would mean that you start out with fully charged batteries for no ongoing carbon footprint.

My fantasy boat is a Southerly 38 with azipods in front of each rudder. A big enough batch of Li-ion or newer generation batteries to give a decent range under power would take care of weekend sailing and a diesel generator with just enough power to maintain cruising speed would extend the range to as much diesel as I can carry for longer cruises or when I've got a deadline and no wind.

The extra weight of batteries would be partially compensated for by a smaller engine, the rest by shaving weight from the ballast, which I believe is in the form a fat cast iron grounding plate

 

[pvb]

Most boats spend most of their time sitting, waiting for someone to sail them. Good solar panels would mean that you start out with fully charged batteries for no ongoing carbon footprint.

My fantasy boat is a Southerly 38 with azipods in front of each rudder. A big enough batch of Li-ion or newer generation batteries to give a decent range under power would take care of weekend sailing and a diesel generator with just enough power to maintain cruising speed would extend the range to as much diesel as I can carry for longer cruises or when I've got a deadline and no wind.

The extra weight of batteries would be partially compensated for by a smaller engine, the rest by shaving weight from the ballast, which I believe is in the form a fat cast iron grounding plate

Any idea what the carbon footprint is of "A big enough batch of Li-ion or newer generation batteries"??

 

[planteater]

I would suggest that electric propulsion might be viable for a specific kind of sailing. A 20ish', easily driven day boat that is typically used at summer weekends could get away with a Torqueedo outboard and a solar panel. Light weight and low maintenance, it would get you off your moorings and back home if the wind dies.

 

[Seajet]

I would suggest that electric propulsion might be viable for a specific kind of sailing. A 20ish', easily driven day boat that is typically used at summer weekends could get away with a Torqueedo outboard and a solar panel. Light weight and low maintenance, it would get you off your moorings and back home if the wind dies.

As long as the boat user never gets into a tide-punching situation, so he or she will have to be a lot better than me now, let alone when I was a novice in 1972.

On a different aspect, 'Green' and 'electricity' just do not belong in the same sentence, how exactly were the motor and battery manufactured, fairy - dust ?!

The same goes for wind turbines, let's see a calculation including the manufacture of all the bits - are they all smelted, moulded, cut, machined etc in places using fossil free fuel inc heating and workers driving to & fro, the people in turbine assembly driving to & from work, the heating for the factory, the Landrovers or ships required to maintain them - have you seen the 6 -jack ship used to install the offshore wind turbines ?! I don't see any sails or green power on that ! The 'green' aspect is utter Bolleaux !

 

[planteater]

The same goes for wind turbines, let's see a calculation including the manufacture of all the bits - are they all smelted, moulded, cut, machined etc in places using fossil free fuel inc heating and workers driving to & fro, the people in turbine assembly driving to & from work, the heating for the factory, the Landrovers or ships required to maintain them - have you seen the 6 -jack ship used to install the offshore wind turbines ?!

All process plant has to be manufactured. Obviously, the lifetime savings are made as a result of fuel requirements (and the unmentionable "D word" - decommissioning)


EDIT - apologies! Got sucked into a GW discussion!

 

[zikzik]

So the OP should have a clear picture by now. Electric power is not yet viable for the sea. It aint green to build or power. As an early adopter, he will be helping to fund future development, but will lose his entire investment in it. Becuse nobody will want his set up once the technology moves on.

I empathise his desire and hope I can save him money. I have a dinghy with a Honda 2.3 outboard. I wanted a clean, quiet solution, so I bought a Torqeedo 1003. It cost twice the price of the outboard and runs for half the time of one tankful of fuel in Poole harbour. A range that fails to get me back from my destination. So guess what. I use the Honda outboard and wish I had saved my money.

 

[Rivers & creeks]

I'm amazed by the closed minds on this - electric propulsion is in its early days - but this is a Practical boat owner forum; most of us enjoy a bit of hands-on experimentation and trial and error. There is no electric solution yet for my 15 ton yacht but I try out new technologies elsewhere on the boat - I was a very early adopter on LED's for instance, and some were a real trial! Instead of saying "No way, it's rubbish" we should be encouraging each other to try new ideas.

I will need a new engine in the next 10 years or so. No way do I want to put in another blooody great lump of iron that owes most of its design to the century before last, sure it will work, but I was hoping we would have moved on from squashing some hydrocarbons so hard that they explode, in the process producing large amounts of noise, vibration and wasted heat.

 

[Tranona]

I'm amazed by the closed minds on this - electric propulsion is in its early days - but this is a Practical boat owner forum;

That is simply not true. Electric propulsion on boats predates diesels. Vast sums have been poured into trying to expand the range of applications, but the simple physics that limit storage of energy make it impossible. While the efficiency of the propulsion motors is good, and there are clearly other benefits, until the energy storage issue is resolved it will not be useful as a power source for seagoing boats. In the meantime the alternative of hybrid has some potential but only in certain types of boat because of size, cost and complexity.

 

[Stemar]

Any idea what the carbon footprint is of "A big enough batch of Li-ion or newer generation batteries"??

Probably horrific, but it's a fantasy. What I really like is silence of electric propulsion. One day, it'll become practical and the carbon footprint will reduce.

On a dust to dust basis, my Snapdragon with its smelly, smokey old Volvo is one of the greenest boats around 'cos she's 40 years old and probably good for another 40, in the same way as an old gas-guzzler is greener than a Toyota Pious 'cos the carbon footprint of all the machines to make it is already amortised.

 

[maxi77]

I'm amazed by the closed minds on this - electric propulsion is in its early days - but this is a Practical boat owner forum; most of us enjoy a bit of hands-on experimentation and trial and error. There is no electric solution yet for my 15 ton yacht but I try out new technologies elsewhere on the boat - I was a very early adopter on LED's for instance, and some were a real trial! Instead of saying "No way, it's rubbish" we should be encouraging each other to try new ideas.

I will need a new engine in the next 10 years or so. No way do I want to put in another blooody great lump of iron that owes most of its design to the century before last, sure it will work, but I was hoping we would have moved on from squashing some hydrocarbons so hard that they explode, in the process producing large amounts of noise, vibration and wasted heat.

Nothing to do with closed minds. Electric propulsion is feasable, it is just quite how you implement it and how practical is really is. If you intend to use stored power in batteries you need a lot of battery to replace your diesel tank. Coupled with the reality that their capacity is non linear, use it frugally and you have a lot, use it at full power and it dissapears in a flash. You can extend this and cut the size of your battery pack by going hybrid using a diesel, petrol or fuel cell generator. That of course can have serious implications on cost as the ideal answer fuel cell is pricey, 850 watts comes in at £23000 for one I looked at and how many watts do you need. Make a marine diesel look cheap for once. Last year I saw a solar boat and every inch of deck space was covered with panels.

The reality so far is non carbon based generation methods are in early days and as a result pricey, inefficient aand non optimised

 

[boomerangben]

I too would love to consider an electric or hybrid propulsion system for my dream boat. Looking at the discussion here, the most important factor is the type of sailor you are. If you are a sail everywhere except into the marina type of person, then maybe electric is feasible. If you are always on a deadline and hate tacking, electric is not going to work. Hark back to the early days of auxiliary yacht engines, which sailors expected them to fail.

"Dust to Dust" analysis is always going to be hard to argue as they would be immensely complex. I would love to know what the environmental impact is of modern exotic metal batteries and how recyclable they are. Are they really better than drilling a hole in the ground?

In my mind I have discarded a system on based on electrical storage as it's only means of power. Yes if you had your own wind turbine/hydro/solar generation system for your say home or business, surplus energy that could be used to charge your boats batteries would be free and therefore take some beating. But it is only realistically going to get you out of the marina and back.

A hybrid system to me would seem to have more mileage (in every sense). Would a modern generator/motor combination be more thermally efficient than a conventional diesel? I suppose it depends on the old diesel. But I guess that is always going to be a close call. But to me the advantages of a hybrid system are more holistic.

First of all, you have a source of significant electrical power on board for all those amp demanding toys. But more subtly, you have much greater flexibility on where you put the engine and its weight, you can install much better noise and vibration insulation. Access to stuffing boxes and stern glands might be made easier and so on. I still think there might be an argument for electric, but I doubt it can be justified on an ecological basis.

 

[prv]

Would a modern generator/motor combination be more thermally efficient than a conventional diesel?

Seems unlikely to me. It works in cars, because they have to have enough power to accelerate rapidly (say up a sliproad onto an elevated motorway, from stopped to 70 up a hill) but then cruise using much less of that power. If you can provide the short-term acceleration from electrical storage, your generator for cruise power needn't be so big. But boats don't work like that.

you have much greater flexibility on where you put the engine and its weight, you can install much better noise and vibration insulation. Access to stuffing boxes and stern glands might be made easier and so on.

Yep, there can definitely be benefits to a remote-mountable engine, especially on craft of unconventional layout or old boats that weren't designed with engines in mind. These tend to use hydraulic drives at present, but electric could be a plausible alternative. No particular greeny benefit though, as you say.

Pete

 

[Tranona]

Nigel Calder is running an EU funded research project on hybrid propulsion using his new Malo 46. One of the objectives is to assess efficiency as he has his previous conventional Malo data for comparison. He wrote up the installation a couple of years ago in YM and no doubt will report his findings when ready.

There are various types of hybrid already in (sort of) production, but mostly aimed at displacement Mobos where the advantages are much more obvious. None of the attempts to build systems for smaller sailboats have got past the "inventor" stage. As Nikki Perryman found out, even the most advanced failed to live up to its hype.