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Electric Boats


peterboat

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On 18/08/2021 at 19:40, tehmarks said:

If you can cruise along at a steady pace using 3kW, I don't really see the need to have a another 17kW in reserve to make up for a lack of anticipation.

I come from a lumpy water background where it seems to be much more common to look after ones diesel engine by routinely running at around 2/3 throttle, both because that's where the engine is more efficient and also because it is much better for it.

 

Endless hours running a big engine outputting just a few horses to achieve 3mph or just to charge batteries will long term risk cylinder glazing and poor compression. 

 

I don't understand why many narrowboaters would rather abuse an engine of twice the necessary Hp by running it at a tiny fraction of its capability just for a 'quiet life', when lumpy water boaters often install a correctly sized engine, run it at an output that's good for it and use sound attenuating multi density, 'lead' lined foams for blissfully silent cruising.

 

I know it's possible to 'silence' a narrowboat engine because I often remark on very quiet boats and am often told about sound insulation and hospital silencers etc.

 

If even for emergency stopping and pushing against a current only a 25Hp diesel is needed, why not save a bundle on the installation, buy a smaller lump, fit modern sound insulation, run it at an output that's good for it, match a nice bid grippy propeller via an appropriate gearbox and save money on fuel as well.

 

 

 

 

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3 minutes ago, Bargebuilder said:

I come from a lumpy water background where it seems to be much more common to look after ones diesel engine by routinely running at around 2/3 throttle, both because that's where the engine is more efficient and also because it is much better for it.

 

Endless hours running a big engine outputting just a few horses to achieve 3mph or just to charge batteries will long term risk cylinder glazing and poor compression. 

 

I don't understand why many narrowboaters would rather abuse an engine of twice the necessary Hp by running it at a tiny fraction of its capability just for a 'quiet life', when lumpy water boaters often install a correctly sized engine, run it at an output that's good for it and use sound attenuating multi density, 'lead' lined foams for blissfully silent cruising.

 

I know it's possible to 'silence' a narrowboat engine because I often remark on very quiet boats and am often told about sound insulation and hospital silencers etc.

 

If even for emergency stopping and pushing against a current only a 25Hp diesel is needed, why not save a bundle on the installation, buy a smaller lump, fit modern sound insulation, run it at an output that's good for it, match a nice bid grippy propeller via an appropriate gearbox and save money on fuel as well.

 

 

 

 

I asked that question some time ago. Hardly anybody does it, certainly most boatbuilders and hire yards don't. Probably because the big engine sizes have become accepted as "normal" -- it's what the engine manufacturers recommend and most boats are fitted with, so anything much smaller would probably be more difficult to sell, however logical it is 😞

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5 minutes ago, IanD said:

I asked that question some time ago. Hardly anybody does it, certainly most boatbuilders and hire yards don't. Probably because the big engine sizes have become accepted as "normal" -- it's what the engine manufacturers recommend and most boats are fitted with, so anything much smaller would probably be more difficult to sell, however logical it is 😞

 

You are spot on of course, and yes, why wouldn't engine manufacturers push the bigger engines in their range.

 

When buying a new boat, I understand why people think bigger must be better, but is it?

 

A modern 25Hp diesel, I know from personal experience only consumes an average of 1/2 litre per hour when run at 1600rpm with the prop only needing 4 or 5 Hp in order to achieve canal cruising speeds; a fuel consumption figure that includes time at tickover past moored boats and in locks.

 

Surely, before we consider investing huge sums of money into going fully electric, we should consider a smaller diesel, running it more efficiently and burning less fuel and using sound attenuation techniques to achieve the silent cruising that we all crave. 

 

 

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22 minutes ago, Bargebuilder said:

 

You are spot on of course, and yes, why wouldn't engine manufacturers push the bigger engines in their range.

 

When buying a new boat, I understand why people think bigger must be better, but is it?

 

A modern 25Hp diesel, I know from personal experience only consumes an average of 1/2 litre per hour when run at 1600rpm with the prop only needing 4 or 5 Hp in order to achieve canal cruising speeds; a fuel consumption figure that includes time at tickover past moored boats and in locks.

 

Surely, before we consider investing huge sums of money into going fully electric, we should consider a smaller diesel, running it more efficiently and burning less fuel and using sound attenuation techniques to achieve the silent cruising that we all crave. 

 

 

I looked at that in depth a couple of years ago, along with parallel hybrids like the Hybrid Marine one.

 

Even with extreme measures (encapsulated engine, sound-deadening, hospital-super-plus silencer, subframe mounting) there's no escaping the fact that you're in a very quiet environment a few feet away from a diesel engine. And even a 20hp diesel is still massively under-used at a typical 4hp when cruising -- better than a 40hp one, but still inefficient, and more so when going slowly or in locks.

 

I came to the conclusion that if you really value *silent* (as opposed to just quiet) cruising electric (with lithium batteries) was the way to go, so long as you can afford it -- which luckily for me, I can. The fuel saving (even over a 20hp diesel) is still significant, even more so if you can use some solar power -- this might not save the world, but it's a small personal contribution to it. In summer if you don't cruise every day then quite possibly fuel consumption will be nil -- and maybe in future more often if charging stations ever appear.

 

If this is too expensive, a small well-soundproofed diesel -- with at least a 3:1 gearbox to avoid the egg-whisk problem -- is a better solution than what is commonly used today. But hardly anybody seems keen to do it...

Edited by IanD
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6 minutes ago, IanD said:

cruising electric (with lithium batteries) was the way to go, so long as you can afford it -- which luckily for me, I can. The fuel saving (even over a 20hp diesel) is still significant,

Silence is indeed golden, in more ways than one. 

 

It must be lovely to hear nothing but the gurgling of the prop in the water from an electric powered boat, but in comparison to installing a 25Hp diesel, a diesel electric setup with super silent generator, lithium batteries, running gear, control gear, solar panels plus their charge controllers, doesn't come cheap unless you are confident to go second hand. In fact, a new super silent generator alone would be of similar cost to a 25Hp inboard diesel.

 

The diesel inboard wouldn't be as silent as the electric, but properly silenced, it could be made quieter than most narrowboats today with 43Hp diesels run at very low revs to their detriment.

 

I'm not sure how relevant fuel economy is between a small diesel inboard and a diesel electric given the huge installation cost disparity.

 

If a 25Hp inboard diesel burns 3 litres of diesel in a 6 hour cruising day, just how much money can you save by going diesel electric and would the payback time have been reached before the diesel electric equipment needs replacing?

 

We know the inboard diesel should be good for 30, 40 or even 50 years, but an electric motor in the bowels of a boat?

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9 minutes ago, Bargebuilder said:

Silence is indeed golden, in more ways than one. 

 

It must be lovely to hear nothing but the gurgling of the prop in the water from an electric powered boat, but in comparison to installing a 25Hp diesel, a diesel electric setup with super silent generator, lithium batteries, running gear, control gear, solar panels plus their charge controllers, doesn't come cheap unless you are confident to go second hand. In fact, a new super silent generator alone would be of similar cost to a 25Hp inboard diesel.

 

The diesel inboard wouldn't be as silent as the electric, but properly silenced, it could be made quieter than most narrowboats today with 43Hp diesels run at very low revs to their detriment.

 

I'm not sure how relevant fuel economy is between a small diesel inboard and a diesel electric given the huge installation cost disparity.

 

If a 25Hp inboard diesel burns 3 litres of diesel in a 6 hour cruising day, just how much money can you save by going diesel electric and would the payback time have been reached before the diesel electric equipment needs replacing?

 

We know the inboard diesel should be good for 30, 40 or even 50 years, but an electric motor in the bowels of a boat?

We're not arguing here; a small properly-soundproofed diesel is a lot cheaper, not as quiet, and can't use solar today or charging stations in future.

 

As I keep saying the fuel saving is not to do with the money, you'll never pay back the higher installation cost -- it's simply wanting to use less fossil fuel, maybe none in summer or the future, and be silent. It's a luxury green(er) propulsion solution which some people think is worth the price. If you don't, install something cheaper and noisier 😉

 

Why would a modern brushless PMAC motor in the (dry) bowels of a boat be a problem?

Edited by IanD
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40 minutes ago, IanD said:

I came to the conclusion that if you really value *silent* (as opposed to just quiet) cruising electric (with lithium batteries) was the way to go, so long as you can afford it --

 

Point of Order...

 

I have had several electric boats pass me recently and none of them were truly silent. I could hear all of them from the bank. A quiet, buzzy humming noise which led me to enquire of each if they were electric, and all of them were.  

 

For truly silent cruising, I think one still needs a horse. 

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3 minutes ago, MtB said:

 

Point of Order...

 

I have had several electric boats pass me recently and none of them were truly silent. I could hear all of them from the bank. A quiet, buzzy humming noise which led me to enquire of each if they were electric, and all of them were.  

 

For truly silent cruising, I think one still needs a horse. 

There are a lot of electric boats who have cut corners on installation to save cost, just like a lot of diesel boats; the end result is that they buzz or whine, I've heard them too.

 

Done properly there's no noise other than the prop, but this costs more money to do...

 

Nothing is as quiet -- or impractical nowadays -- as a horse. And you get free material to add to your compost heap, along with your composting toilet waste...;-)

Edited by IanD
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4 minutes ago, IanD said:

 

 

Nothing is as quiet -- or impractical nowadays -- as a horse. And you get free material to add to your compost heap, along with your composting toilet waste...;-)

 

The bit that puzzles me, is how do you get the horse to use the composting bog?

 

 

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1 hour ago, IanD said:

I asked that question some time ago. Hardly anybody does it, certainly most boatbuilders and hire yards don't. Probably because the big engine sizes have become accepted as "normal" -- it's what the engine manufacturers recommend and most boats are fitted with, so anything much smaller would probably be more difficult to sell, however logical it is 😞

I agree. But there's another thread running at the moment where a newbie is asking about engine size for a new build and the responses from forum regulars include:

 

"Go large.  You don't have to use full power every day and in the range you are talking about the fuel consumption will not be significantly different whatever you fit."

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Is this the right thread to ask whether a hydraulic-drive boat be suitable for conversion to electric drive?

 

I have been looking at broads-style single level cruisers recently (came very close to buying a Broom DC30 but it was just too much work to take on) and they seem to use a small-ish diesel engine to drive a hydraulic pump which turns the prop - would it be easy/feasible/possible to replace the diesel with an electric motor?

 

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12 minutes ago, MtB said:

 

Point of Order...

 

I have had several electric boats pass me recently and none of them were truly silent. I could hear all of them from the bank. A quiet, buzzy humming noise which led me to enquire of each if they were electric, and all of them were.  

 

For truly silent cruising, I think one still needs a horse. 

 

I've only (knowingly) heard one leccy-boat, as he passed I asked him, in all innocence,  if his bow thruster was stuck in the on 'on' position, he was not best pleased and didn't bother to answer, maybe it was stuck, and he was a bit miffed, or maybe it was his new electric boat and he realised he'd made an expensive mistake.

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38 minutes ago, Bargebuilder said:

Silence is indeed golden, in more ways than one. 

 

It must be lovely to hear nothing but the gurgling of the prop in the water from an electric powered boat, but in comparison to installing a 25Hp diesel, a diesel electric setup with super silent generator, lithium batteries, running gear, control gear, solar panels plus their charge controllers, doesn't come cheap unless you are confident to go second hand. In fact, a new super silent generator alone would be of similar cost to a 25Hp inboard diesel.

 

The diesel inboard wouldn't be as silent as the electric, but properly silenced, it could be made quieter than most narrowboats today with 43Hp diesels run at very low revs to their detriment.

 

I'm not sure how relevant fuel economy is between a small diesel inboard and a diesel electric given the huge installation cost disparity.

 

If a 25Hp inboard diesel burns 3 litres of diesel in a 6 hour cruising day, just how much money can you save by going diesel electric and would the payback time have been reached before the diesel electric equipment needs replacing?

 

We know the inboard diesel should be good for 30, 40 or even 50 years, but an electric motor in the bowels of a boat?

The problems for your idea are by 2050 ICE engines are banned in boats secondly will diesel still be available in say 15 years for boats? And the biggy how much will diesel cost by then?

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6 minutes ago, Bacchus said:

Is this the right thread to ask whether a hydraulic-drive boat be suitable for conversion to electric drive?

 

I have been looking at broads-style single level cruisers recently (came very close to buying a Broom DC30 but it was just too much work to take on) and they seem to use a small-ish diesel engine to drive a hydraulic pump which turns the prop - would it be easy/feasible/possible to replace the diesel with an electric motor?

 

 

Any hydraulic system is inefficient to very inefficient when compared to a mechanical one. It was used in those hire boats to it a transverse engine to give as much cabin space as possible while keeping the engine and passengers as far apart as practical. It also, once correctly set up and glassed in, does away with any need for shaft alignment so arguably gives quieter/more vibration free motoring. Note that nothing here is to do with efficiency.

 

Those boats may well also use one of the less efficient hydraulic pump and motor.

 

The hydraulic mounting plate MIGHT make motor mounting easier, but it is so low in the boat would be asking for ongoing expensive motor problems. It is in the keel. If you decided to overcome that by driving the pump by an electric motor, then you are stuck with the inefficiencies and thus a larger (guess 25% to 30%) battery bank. I suspect you would need to use something like a toothed belt drive from a higher mounted electric motor, and that would impinge upon back cabin space and need the mountings made up and glasses onto the hull.

 

 

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22 minutes ago, David Mack said:

 

"Go large.  You don't have to use full power every day and in the range you are talking about the fuel consumption will not be significantly different whatever you fit."

That's what you would expect, but it doesn't mean that going big is better for the engine or its fuel consumption or even for the noise level in the cockpit if proper noise attenuating methods and materials are used.

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22 minutes ago, Bacchus said:

Is this the right thread to ask whether a hydraulic-drive boat be suitable for conversion to electric drive?

 

I have been looking at broads-style single level cruisers recently (came very close to buying a Broom DC30 but it was just too much work to take on) and they seem to use a small-ish diesel engine to drive a hydraulic pump which turns the prop - would it be easy/feasible/possible to replace the diesel with an electric motor?

 

I have converted a broads cruiser to electric drive already worked really well, the previous motor was a BMC 1500 and with a 2 to 1 gearbox did 2000 rpm at 8mph, the electric motor did 6 mph at about 50 amps. I have sold it and removed the electric motor for my boat, I have since helped to fit a Lombardini LDW502m to it with a 2 to 1 drive, we are having to reprop it because of the lack of torque, it just cant rev up unlike the electric motor which had far less HP but clearly for more torque.

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5 minutes ago, peterboat said:

The problems for your idea are by 2050 ICE engines are banned in boats secondly will diesel still be available in say 15 years for boats? And the biggy how much will diesel cost by then?

I'm guessing that most of us are not thinking as far forward as 2050; if only!

 

As for the availability of diesel, nobody knows, but if nobody is using oil for vehicles or heating then it could be that the remaining reserves will last pretty well. Supply and demand is a huge driver of fuel costs and who knows what will happen when none of us are using much of it any more.

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31 minutes ago, Bacchus said:

Is this the right thread to ask whether a hydraulic-drive boat be suitable for conversion to electric drive?

 

I have been looking at broads-style single level cruisers recently (came very close to buying a Broom DC30 but it was just too much work to take on) and they seem to use a small-ish diesel engine to drive a hydraulic pump which turns the prop - would it be easy/feasible/possible to replace the diesel with an electric motor?

 

Why not just replace the hydraulic motor with an electric one and save the losses in a pump, motor and pipes

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1 minute ago, Bargebuilder said:

I'm guessing that most of us are not thinking as far forward as 2050; if only!

 

Quite. 

 

I reckon many of us here will be knocking on for 100 years old by 2050, so if this impacts on our boating in any way, we shall be delighted!

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1 minute ago, Bargebuilder said:

I'm guessing that most of us are not thinking as far forward as 2050; if only!

 

As for the availability of diesel, nobody knows, but if nobody is using oil for vehicles or heating then it could be that the remaining reserves will last pretty well. Supply and demand is a huge driver of fuel costs and who knows what will happen when none of us are using much of it any more.

Reserves arnt the problem its the pollution from it that is the issue! Fossil fuel companies are spending billions to con us into thinking its ok but it seems to be failing which is good for the human race

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1 minute ago, ditchcrawler said:

Why not just replace the hydraulic motor with an electric one and save the losses in a pump, motor and pipes

 

I will look further into it, especially after what @peterboat says, but my understanding was that the gearbox/drive can be mounted externally obviating the need for moving parts going through the hull - I could be completely wrong on that of course (c:

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1 minute ago, Bacchus said:

but my understanding was that the gearbox/drive can be mounted externally obviating the need for moving parts going through the hull - I could be completely wrong on that of course

 

You mean like an out-drive (leg) ?

 

Our Fairline 23 when on the Thames (the Hard standing)

 

 

 

 

 

DSCF0004a.jpg

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20 minutes ago, Tony Brooks said:

 

Any hydraulic system is inefficient to very inefficient when compared to a mechanical one. It was used in those hire boats to it a transverse engine to give as much cabin space as possible while keeping the engine and passengers as far apart as practical. It also, once correctly set up and glassed in, does away with any need for shaft alignment so arguably gives quieter/more vibration free motoring. Note that nothing here is to do with efficiency.

 

Those boats may well also use one of the less efficient hydraulic pump and motor.

 

The hydraulic mounting plate MIGHT make motor mounting easier, but it is so low in the boat would be asking for ongoing expensive motor problems. It is in the keel. If you decided to overcome that by driving the pump by an electric motor, then you are stuck with the inefficiencies and thus a larger (guess 25% to 30%) battery bank. I suspect you would need to use something like a toothed belt drive from a higher mounted electric motor, and that would impinge upon back cabin space and need the mountings made up and glasses onto the hull.

 

 

 

I assumed that the pump could be mounted pretty much anywhere because all it has to do is drive fluid through a pipe, but, yes, it may end up being fairly inefficient. Probably not a major consideration for hire boats!

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3 minutes ago, peterboat said:

Reserves arnt the problem its the pollution from it that is the issue! Fossil fuel companies are spending billions to con us into thinking its ok but it seems to be failing which is good for the human race

I'm not questioning you, but you've mentioned the billions that oil companies are spending on pro oil propaganda many times, but what are they spending it on?

 

Perhaps my life is a sheltered one, but I can't think of an occasion when I've been aware of being influenced to keep using or to use more oil.

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