Electric Boats

[John100156]

Mmmm PV and changes in FIT's hence payback for homes really killed/slowed significant investment in that field of research, but as the cost of E-energy increases (paradox?) it seems to be gaining momentum again. Difficult to justify on payback but I too will be fitting a 4kW array to a property we hope to move into in Feb., plus of course a heat pump. The latter (only because it has an inefficient boiler at present but broadly a similar argument gas/E-hp). I have been specifying and ran a commercial business many years ago installing heat pumps that produced low temperature as well as domestic hot water, back then a lot of sceptics were saying never for domestics, but we will see a lot more installed in the future.

VR is also receiving investment at Imperial College, as you may know.

As to being a pessimist/realist , I think we all need to be more enthusiastic, I really do not believe that EBs are an unrealistic proposition for quite a high percentage of those boats being used as they currently are (does not fit all I agree), I think though its inevitable, we will see some significant developments in the short-term (5-10 years) IMHO, well I do hope so - optimist!

 

[John100156]

I feel a poll might be fun, as the OP sees fit to inform this discussion - EBs in the next 10 years for leisure boats up to say ????ft

NO 'pessimist/realist' or YES 'optimist/enthusiast' but I fear I may get a battering....!

 

[kashurst]

I feel a poll might be fun, as the OP sees fit to inform this discussion - EBs in the next 10 years for leisure boats up to say ????ft

NO 'pessimist/realist' or YES 'optimist/enthusiast' but I fear I may get a battering....!

Probably, but I agree with you. In ten years time there will be realistic EBs running about. There are already some great electric boats. Will they do 100 miles at 25 knots? I think not, 50 - 60 possibly. I was really dissapointed with Princess when they did the R35 with hydrofoils - I expected it to lift out of the water, all it seems to do is make tight turns. If Candela can make a 25" electric hydrofoil, they and others can make a 35" hydrofoil and it will just get better as battery design advances. Has anyone made a super slim hulled electric catamaran yet?
Electric cars are creating a huge amount of investment as it is a massive potential market. In only the four years I have been driving an EV the difference is astounding. That technology will accelerate and pass on to boats, planes all sorts.

 

[gordmac]

Electric boats I would suggest are even more problematic than cars. Unlike cars, for any sort of speed you need a lot of power and you can't exactly plug it in to your house to recharge it like a car.
People who are happy to travel at walking pace seem to be happy with sails although electric drive is more suited to them. Still the issue of how do you charge the batteries though.

 

[John100156]

Electric boats I would suggest are even more problematic than cars. Unlike cars, for any sort of speed you need a lot of power and you can't exactly plug it in to your house to recharge it like a car.
People who are happy to travel at walking pace seem to be happy with sails although electric drive is more suited to them. Still the issue of how do you charge the batteries though.

Surely PV contributions during the day, shore power when in the marina (great if like us, this is included in the berthing fees, although they will rise of course as numbers increase as will the need to rewire) and a Genny using alternative fuel? Until technology renders that too unnecessary!

A lot of leisure boats often (not all) are left idle and may make short trips or often sit for days on the hook before moving on when out, energy use would need managing, although I cant quite find a reasonable argument in the event of having to run for cover in an emergency, when caught out - which does happen even with the best passage plans!

 

[gordmac]

I wonder how many sail boats live on a pontoon berth? Probably a significant proportion I suppose but even then how much would be required to get enough charging points, I suspect the cost for charging the boat would exceed the cost of diesel although for all the diesel they should use it isn't significant? For fast boats even less viable. To replace the diesel tank in my boat would need about a dozen tons of battery, or three times what the boat weighs!

 

[Bigplumbs]

Sorry I haven’t got time to read through the entire thread. My comment is that the energy density of diesel is about 100x more than Li-ion batteries. When you factor in the better efficiency of electric motors you end up with a difference of around 25x. So if your boat currently has a 1,000 liter fuel tank then you would need getting on for 25 tonnes of batteries to give the boat the same performance envelope as you enjoy today (although not in reality as your boat wouldn’t go so well with an additional 25 tonnes on board I’m guessing).

For now and probably for quite some time given the very shallow improvement in battery energy density since the 1990s electric boats will only make sense for slow displacement vessels with low range, or foil or planing cats that have short routes like some ferries. The technology is totally impractical for the vast majority of leisure boating.

Spot on

 

[John100156]

I wonder how many sail boats live on a pontoon berth? Probably a significant proportion I suppose but even then how much would be required to get enough charging points, I suspect the cost for charging the boat would exceed the cost of diesel although for all the diesel they should use it isn't significant? For fast boats even less viable. To replace the diesel tank in my boat would need about a dozen tons of battery, or three times what the boat weighs!

I wonder how much an electric motor weighs compared to a diesel engine and train? I have no idea. Seems to work OK on the 60ft CAT above, without new battery/energy source technology, or will the world grind to a stop when all the oil runs out? We need to be encouraging new fuel sources and EBs and the like now, IMHO.

 

[gordmac]

A quick Google gives a 200kw motor weight of 1.8 ton, seems very high. Next one 1.2 ton. I struggle to believe car ones would be that heavy.

 

[penfold]

How long is a piece of string? Automotive motors are mostly in the 100-200kg bracket, generally with liquid cooling. 1.8t for 200kW will be a continuously rated industrial motor with air cooling that is practically passive/by convection. They will put out similar amounts of power, but probably at differing RPM; the industrial motor might top out at 1200 or 1500 rpm whereas the automotive motor is doing perhaps 6-8000 rpm.

 

[gordmac]

That makes sense. For a boat rather than a car the continuous rating type would be more realistic. A couple of hundred kilo less for a motor is not significant compared to the extra tons of batteries.

 

[Alicatt]

Just for information this is the charging times for a Tesla Model 3 (from Google)
I think this underlines Henry's comments about the infrastructure.
Most domestic supplies are 60amp (14Kw) which has to handle all the devices in the house as well as charging a car.
Heat your hot water with an immersion heater and boil a kettle and you could be getting close to overloading the supply.

Method	kW	Charging time (empty to full)
Standard three-pin plug	2.3	37.75 hours
Dedicated home charging point	7.4	11.75 hours
Fast charger	22*	8 hours* (vehicle limited to 11kW)
Rapid charger	Up to 250	22 minutes

Here we are limited to 40A @230V or around 9kW, unless your house is wired 3phase
The original builder of my house was a joiner and had his workshop in the garage so the house was wired for 3phase 380V. Oh the fun and joy I had when I first moved in and found that some sockets were off the yellow and the socket next to it was on the blue... floating charges on the earth! Took a bit of thought to get all the AV and computer equipment through out the house all on to the same phase to eliminate the floating charge and the mis-synced video

My youngest daughter has a BMW EV and is waiting for the infrastructure to be upgraded so that she can put a fast charger in her property, the house is currently wired to a single phase, at the moment the wiring in the street can't handle all the extra EVs that are there she has to go and seek charging points in car parks etc. to keep her car topped up.