Is diesel-electric or all-electric the future?

[danstanford]

Originally Posted by moseriw

Thought this is a cruisers forum though I expected partipiciants with boats > 30 ft. but it looks like a sailing in my swiming pool forum

To be precise, it is a forum dedicated to learning and discussion with respect to cruising sailboats. It is not dedicated to people who are disrespectful and rude nor to trolls.

If you intend to judge the people here on the size of their boats, I don't think you fit the aims and objectives of the crowd. You will certainly miss some good discussion from people who don't even own a boat let alone one bigger than 30'.

I don't have a suggestion as to what forum might be suitable for you.

[moseriw]

b) it's no problem at all coupling it or using it as a house bank.

Yes, yes and for the air condition too

[Adelie]

Originally Posted by moseriw

And yes I know someone who goes electric with a 36 feeter.
He sails right to the entrance of the marina and the rushes in with 6 knots for 10 minutes to proof himself how good his motor is.

Without wind and 8 miles to go he reduces speed to 2 knots after calculating if he will make it or not.

I hope he never ever needs a powerful engine beeing adrift.

With a 150Ahr batt at 48v he should be able to motor at 4.0kt for that distance no problem.

[SaylorMade]

These electricification threads seems to go on and on with the same arguments, could we boil it down a bit?
Here is my take:

1. It is a bit pricey, but it can save a lot on maintenance and complexity for some boats
2. If you plan to motor a lot, it is not for you, it simply isn't
3. Solar is great for small loads, but for moving or heating a boat is it not really viable
4. If you mostly use the engine for sailing in and out of the marina and/or can live with very low speeds if the wind dies, it is great
5. In terms of CO2 it is a silly discussion, the greater picture considered

I am not saying that the above points are correct, but let's remember that we all have different needs. And where I live, 90 percent of the sailboats fits in category 4.

[Corvidae]

If you're worried about range with an electric boat, install a generator. You're going to need to fill the battery banks one way or another. Solar/wind/hydro won't keep up all the time, so you need to fill that gap. A 10 to 20kw generator isn't that hard to stuff into most boats somewhere, and gives you continuous motoring capability. Even if it just sits there 95% of the time, it's worth it to have to continuous power available when needed.

[Dockhead]

Originally Posted by Corvidae

If you're worried about range with an electric boat, install a generator. You're going to need to fill the battery banks one way or another. Solar/wind/hydro won't keep up all the time, so you need to fill that gap. A 10 to 20kw generator isn't that hard to stuff into most boats somewhere, and gives you continuous motoring capability. Even if it just sits there 95% of the time, it's worth it to have to continuous power available when needed.

In my neck of the woods, a 20kW genset costs about 3x what a 20kW prime mover with marine gear costs. And that's not even getting to the electric motor and battery bank.



If you're going to have a diesel engine on board, you really want it directly coupled to your prop shaft. Anything else is a big waste of money and efficiency.



Electric makes sense in some cases, but in my opinion, exclusively when you get enough power from sources OTHER than a diesel engine, and especially good, if you're getting it from plugging in somewhere.

[Corvidae]

Originally Posted by Dockhead

In my neck of the woods, a 20kW genset costs about 3x what a 20kW prime mover with marine gear costs. And that's not even getting to the electric motor and battery bank...

The 'other' gear, is another generator. Even if you have a diesel drive engine, you still need a generator. So now you have two engines, either burning two different fuels, or twice the diesel problems. Having gone from 3 diesels down to 1 diesel on my own boat, I can say for a fact it's a much easier system to deal with.

And if your genset is costing 3x the price of the same size diesel. Either you're getting really screwed on generator price, or getting an incredible deal on a motor.

[waterman46]

Originally Posted by Adelie

The don’t even make gas powered SUVs with that range for less the $50k so you are setting up impossible requirements, especially as inflation drives up the cost of all vehicles as time goes on.

Now we are really off-topic but what? There are dozens of 2021 gas powered SUV's on the market for less than $50K including Cadillac and Mercedes. With gas, you have infinite range since a fill-up only takes 5 minutes.

What we need is a universal battery design that allows us to pull into a station and exchange our discharged battery for a fully charged battery in the same 5 minutes.

[noelex 77]

Originally Posted by Corvidae

Even if you have a diesel drive engine, you still need a generator.

A generator is not essential.

With improvements in solar, battery technology, and alternator output generators are becoming less common. If you want air conditioning, at least with a decent run time, a generator is essential, but otherwise doing without a generator is perfectly feasible. This option has advantages with improved reliability and reduced maintenance time.

[Nidnoi_V]

Hi all here is the calculation i got from muliple websites



for Dielsel KW Saildrive compared to Electric KW a



Dielsel effectivness is 36,5% at the probs



the calcultation would then be the following based on 57HP Yanmar

(57*0,73549875)*1000 = 41,9 KW

at the prob that would be 36,5% of 41,9 KW =15,3 KW

[SaylorMade]

Originally Posted by Nidnoi_V

Hi all here is the calculation i got from muliple websites



for Dielsel KW Saildrive compared to Electric KW a



Dielsel effectivness is 36,5% at the probs



the calcultation would then be the following based on 57HP Yanmar

(57*0,73549875)*1000 = 41,9 KW

at the prob that would be 36,5% of 41,9 KW =15,3 KW

I don't think that is correct. The effectiveness of 36 percent, sounds more like the percent of energy in the fuel, that is converted into thrust.
That is something completely different.

[Dockhead]

Originally Posted by SaylorMade

I don't think that is correct. The effectiveness of 36 percent, sounds more like the percent of energy in the fuel, that is converted into thrust.
That is something completely different.

Indeed. A kW -- by definition -- is a kW, whether it comes from an electric motor, a diesel engine, a steam engine, or two trolls cranking hand cranks.


These magic electric kilowatts are a fantasy.

[Corvidae]

Originally Posted by noelex 77

A generator is not essential.

With improvements in solar, battery technology, and alternator output generators are becoming less common. If you want air conditioning, at least with a decent run time, a generator is essential, but otherwise doing without a generator is perfectly feasible. This option has advantages with improved reliability and reduced maintenance time.

Living in a cave is feasible. Doesn't mean anyone wants to do it. It's also much easier to run limited on small boats, with only one or two people on them. Doesn't mean it's in any way a comfortable way to live.

[noelex 77]

Originally Posted by Corvidae

Living in a cave is feasible. Doesn't mean anyone wants to do it. It's also much easier to run limited on small boats, with only one or two people on them. Doesn't mean it's in any way a comfortable way to live.

I think it is rather old fashioned thinking to equate not having a generator to “living in a cave”. Solar panels and battery technology has moved on from those days. Additional systems such as the ready availability of high powered alternators and energy efficient appliances (such as LED lighting) has also contributed.

With a well designed electrical system solar/wind can provide all the comforts (unless you need air conditioning). Indeed the greatest comfort is time to enjoy and explore new locations. This is enhanced by installing a simple, reliable power generation system that requires minimal maintenance and repair. Waiting at a port for parts or a technician to sort out a problem is not luxury living.

There is no perfect answer. As you have an electric drive, a generator is essential in your case to achieve a reasonable range under power, but it is a mistake to believe that a generator would otherwise always be needed for comfortable living on a boat.

[Nidnoi_V]

Originally Posted by SaylorMade

I don't think that is correct. The effectiveness of 36 percent, sounds more like the percent of energy in the fuel, that is converted into thrust.
That is something completely different.

you are corect did some more research and Roughly maxium KW is



HP/1,341)*1000=KW



65% of KW = Max KW at the probs

however the lowerr RPM the KW at the probs are much lower

however at lower speed the KW Per horse power is less so a rough calcultion on 45-50% should give a good indication on Probs KW