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Electric motor and propeller selection for electric/hybrid boats


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I've been having a discussion off-forum with a couple of people about this, and thought that some of this might be interesting to anyone on CWDF who is also confused about conflicting information or claims (of which there are plenty) or perhaps doesn't understand how such beasts are actually designed -- prop choice in particular seems to have a lot of mythology attached to it. It's a bit long and technical so feel free to skip or ignore as desired... 😉

 

[names have been removed since this was not a public conversation]

 

You're correct that electric motor power/torque ratings -- including PMAC -- depend on how cool they're kept and how long the power is sustained for. This is especially true of air-cooled motors (and controllers) like the TEMA -- and the 40C rating is reasonable for a motor inside a boat engine room in the UK, regardless of what TEMA said. And this is all linked to how you think they're going to be used, which is especially important for a boat -- narrow or not... 😉

PMAC motors produce a flat torque (power proportional to rpm) up to their rated rpm, and above this the torque drops off and the power increases more slowly. I'm going to use the water-cooled Engiro 12013 as an example because there is comprehensive data for this in the datasheet (attached), then see how this applies to the air-cooled TEMA SPM132-12.

The Engiro 12013 3-phase PMAC motor is rated as follows:

48V continuous : 134nm@1080rpm=15kW, 382A current per phase
96V continuous : 134nm@2180rpm=31kW, 382A current per phase

Note that the motor limits are set by torque and current because these determine how hot it gets (water-cooled), so the only way to get more power is to run faster which also means using a higher supply voltage. At 48V the efficiency is 91% so the motor will be dissipating 1.5kW of heat, at 96V it's 95% so the heat dissipation is the same 1.5kW but the output power (and rpm) are doubled.
 
These continuous ratings are used for marine applications (especially on inland waterways) because apart from brief emergencies the only time you really need high power is when running against a current, and you need to be able to do this for up to a couple of hours or more. A propeller absorbs power rising with the cube of rpm, and would normally be selected to allow the motor maximum continuous power to be realised; for this motor (15kW/20hp@1080rpm) Vicprop suggests 17.5" x 11.7", coincidentally almost identical to that for a Beta 43... 🙂
 
If we now keep the same prop and look at peak power, this is 26kW from the data and by looking at the motor design curves. Since prop power goes up as rpm^3 this will happen at 1300rpm where torque will be 190nm, and phase current will be 660A.  Efficiency drops to 85% so the motor will dissipate 3.5kW of heat, which is why it can't do this for very long.
 
The other thing that affects the usable power ratings -- short and long-term -- is the controller used. I'll use numbers for the Sevcon Gen 4 Size 6 since I have a detailed data sheet for this, the relevant page is attached. This is rated at 650A peak (for 2mins) but this drops to 260A continuous when air-cooled -- however when water cooled (like Finesse do) the long-term limit will be much higher, certainly higher than the motor (380A). I don't know what controller you used but given that your TEMA motor is air-cooled I expect the controller will be as well -- is this the case?
 
At lower rpm the power also drops as rpm^3, so for cruising at 3kW the motor would be running at 630rpm. So we now have the following for this optimum-sized (17.5" x 11.7") prop:
 
Peak power : 26kW (190nm/660A) @ 1300rpm
Continuous : 15kW (134nm/380A) @ 1080rpm
Cruising : 3kW @ (76A) 630rpm
 
This is pretty close to what Ricky Lee at Finesse does, he's built a *lot* of hybrid boats and these have been tested at full power for a couple of hours or more by both Finesse and customers (e.g. going up the Trent, out in the Wash) -- but note that both motor and controller are water-cooled to allow this.
 
Let's now see what happens if we overprop. If we drop the continuous rpm by 20% (860rpm) then the power also drops by 20% to 12kW since torque is constant (134nm), and Vicprop gives a 19.2" x 13.9" prop. Peak power is still 26kW (290nm) so this happens at 1110rpm, cruising (3kW) is at 540rpm. Now we get:
 
Peak power : 26kW (190nm/660A) @ 1110rpm
Continuous : 12kW (134nm/304A) @ 860rpm
Cruising : 3kW (76A) @ 540rpm
 
So in exchange for 20% lower rpm the continuous power and current has also dropped by 20% to 12kW. The same is true for any amount of overpropping; you could drop rpm and power by 40% to end up with 9kW at 650rpm and a 21.5" x 17" prop. But all these numbers are defined by the continuous torque rating of the motor, in this case 134nm.
 
Now looking at your TEMA 132-12, the continuous torque rating is 111nm which at 1000rpm means 11.5kW, for this Vicprop suggests 17.3" x 11.7" -- almost exactly the same as for the Engiro (and Beta 43). Assuming the same peak/continuous torque ratio as the SPM132-1 (175/70=2.5:1) the peak torque for the SPM132-12 will be 276nm. Doing the same calculations as above, we get:
 
Peak power : 29kW (278nm) @ 1360rpm
Continuous : 11.5kW (111nm) @ 1000rpm
Cruising : 3kW @ 630rpm
 
So the maximum power for emergencies and rpm for cruising are very similar to the Engiro, but the continuous power *with a prop sized like this* is 23% lower -- this is because water cooling allows higher continuous powers, exactly as you said 🙂
 
If you now oversize the prop (as you have done) then power and rpm will both drop because torque is unchanged, just like the Engiro example above. Again using the Victron numbers (suggested prop size 18.2" x 12.9", equivalent to your 19" x 12"), we get the following:
 
Peak power : 25kW (278nm) @ 1170rpm
Continuous : 10kW (111nm) @ 860rpm
Cruising : 3kW @ 580rpm
 
This means you're about 14% overpropped with the 19" x 12" and the maximum continuous power/speed would be 10kW@860rpm,. which IIRC is what you found...
 
Going to 20" x 14", the Vicprop numbers for an equivalent 19.6" x 14.7" prop are:
 
Peak power : 21kW (278nm) @ 1050rpm
Continuous : 8.4kW (111nm) @ 730rpm
Cruising : 3kW @ 520rpm
 
So this is 27% overpropped compared to the "optimum" -- 27% lower power at 27% lower rpm.
 
The key point here is that overpropping reduces the power of the motor in exchange for lower rpm and lower noise. Your SPM132-12 would be 12kW continuous (TEMA headline rating) at 1040rpm, but as you drop the rpm (with bigger props) the power also drops -- 11.5kW/1000rpm with 17" x 12", 10kW/860rpm with 19" x 12", 8.4kW/730rpm with 20" x 14".
 
Again these numbers are the power that can be sustained for long enough for upstream travel on rivers, which is when high power is needed. For use on still canals -- cruising or in emergencies -- it's perfectly acceptable to overprop and get lower noise and lower rpm in exchange for lower sustained power.
 
I don't have the detailed numbers for the Bellmarine motor, but if it's rated at 15kW/1500rpm (which I think it is) this would give the following (again, from Vicprop).
 
Optimum prop size : 14.4" x 8.5" (equivalent to the 15" x 8" actually fitted):
Continuous power : 15kW @ 1500rpm
Cruising : 3kW @ 880rpm
 
These are *much* higher (+39%) rpm with a *much* smaller prop than either the Engiro or TEMA motors, because the Bellmarine motor is lower torque/higher rpm -- it's really too high for direct drive, the normal recommendation is to try and keep to not much over 1000rpm. It's one reason I rejected using this motor -- or any of the others running at this speed, or even faster (1800rpm) in some cases -- and why I chose the Engiro (as did Finesse, but theirs is a customized version). Prop noise increases rapidly with rpm due to increased turbulence, which is why a small high-speed prop isn't a good idea on a quiet low-speed boat like on the canals.
 
Overpropping with a bigger prop (like with the TEMA) would drop both rpm and noise but would also reduce the maximum power, if this is acceptable. If lower rpm/noise without this power loss in desired, then the Bellmarine motor would have to be replaced with one designed to run at lower rpm, such as the Engiro 12013 -- or the TEMA, though the continuous power of this is lower because of air cooling (which also makes more noise and dumps heat into the engine space instead of the canal).
 

I wouldn't like to vouch for the absolute accuracy of the Vicprop sizing down to this level of accuracy, there's a mention about only loading the engine to 90% but it's not clear how this affects the numbers -- but they do seem to be pretty close to real; life looking at various recommendations for prop sizing or what people have measured.

 

But the principles about how choosing/sizing/overpropping works with electric motors on canals are definitely correct:

 

-- if you want to get the maximum continuous power out of an electric motor for upstream river travel, match the prop size to the motor rating (continuous power/rpm)

-- water cooling both motor and controller will give more continuous power out of a given motor than air cooling, reduce motor noise, and keep the engine room cooler

-- if you're willing to accept lower power or don't anticipate ever using the boat upstream on rivers, overpropping will give lower rpm and noise than a matched prop

-- for a quiet electric boat with direct drive avoid motors with rated speed much above 1000rpm -- or overprop them to reduce rpm... 😉

 
Hope this helps people understand how all this electric motor/prop stuff works, because a lot of it is really *not* obvious or intuitive... 😉
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ENGIRO_Datasheet_205W_12013_ABC_V004(4).pdf

Edited by IanD
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51 minutes ago, ditchcrawler said:

 

Serves you right for reading it all 😝

I did say it was long and technical and anyone not interested (or who found it too difficult...) shouldn't bother reading it -- but I guess I should have expected that some people would rather snipe or whinge instead... 😉

Edited by IanD
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20 minutes ago, IanD said:

I did say it was long and technical and anyone not interested (or who found it too difficult...) shouldn't bother reading it -- but I guess I should have expected that some people would rather snipe or whinge instead... 😉

 

It was a 'joke' Ian, remember those?

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1 hour ago, MtB said:

 

It's not Christmas. 

 

Not until the end of next month.

Though you wouldn't think it given the rash of Xmas adverts... 😞

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15 hours ago, IanD said:

I've been having a discussion off-forum with a couple of people about this, and thought that some of this might be interesting to anyone on CWDF who is also confused about conflicting information or claims (of which there are plenty) or perhaps doesn't understand how such beasts are actually designed -- prop choice in particular seems to have a lot of mythology attached to it. It's a bit long and technical so feel free to skip or ignore as desired... 😉

 

[names have been removed since this was not a public conversation]

 

You're correct that electric motor power/torque ratings -- including PMAC -- depend on how cool they're kept and how long the power is sustained for. This is especially true of air-cooled motors (and controllers) like the TEMA -- and the 40C rating is reasonable for a motor inside a boat engine room in the UK, regardless of what TEMA said. And this is all linked to how you think they're going to be used, which is especially important for a boat -- narrow or not... 😉

PMAC motors produce a flat torque (power proportional to rpm) up to their rated rpm, and above this the torque drops off and the power increases more slowly. I'm going to use the water-cooled Engiro 12013 as an example because there is comprehensive data for this in the datasheet (attached), then see how this applies to the air-cooled TEMA SPM132-12.

The Engiro 12013 3-phase PMAC motor is rated as follows:

48V continuous : 134nm@1080rpm=15kW, 382A current per phase
96V continuous : 134nm@2180rpm=31kW, 382A current per phase

Note that the motor limits are set by torque and current because these determine how hot it gets (water-cooled), so the only way to get more power is to run faster which also means using a higher supply voltage. At 48V the efficiency is 91% so the motor will be dissipating 1.5kW of heat, at 96V it's 95% so the heat dissipation is the same 1.5kW but the output power (and rpm) are doubled.
 
These continuous ratings are used for marine applications (especially on inland waterways) because apart from brief emergencies the only time you really need high power is when running against a current, and you need to be able to do this for up to a couple of hours or more. A propeller absorbs power rising with the cube of rpm, and would normally be selected to allow the motor maximum continuous power to be realised; for this motor (15kW/20hp@1080rpm) Vicprop suggests 17.5" x 11.7", coincidentally almost identical to that for a Beta 43... 🙂
 
If we now keep the same prop and look at peak power, this is 26kW from the data and by looking at the motor design curves. Since prop power goes up as rpm^3 this will happen at 1300rpm where torque will be 190nm, and phase current will be 660A.  Efficiency drops to 85% so the motor will dissipate 3.5kW of heat, which is why it can't do this for very long.
 
The other thing that affects the usable power ratings -- short and long-term -- is the controller used. I'll use numbers for the Sevcon Gen 4 Size 6 since I have a detailed data sheet for this, the relevant page is attached. This is rated at 650A peak (for 2mins) but this drops to 260A continuous when air-cooled -- however when water cooled (like Finesse do) the long-term limit will be much higher, certainly higher than the motor (380A). I don't know what controller you used but given that your TEMA motor is air-cooled I expect the controller will be as well -- is this the case?
 
At lower rpm the power also drops as rpm^3, so for cruising at 3kW the motor would be running at 630rpm. So we now have the following for this optimum-sized (17.5" x 11.7") prop:
 
Peak power : 26kW (190nm/660A) @ 1300rpm
Continuous : 15kW (134nm/380A) @ 1080rpm
Cruising : 3kW @ (76A) 630rpm
 
This is pretty close to what Ricky Lee at Finesse does, he's built a *lot* of hybrid boats and these have been tested at full power for a couple of hours or more by both Finesse and customers (e.g. going up the Trent, out in the Wash) -- but note that both motor and controller are water-cooled to allow this.
 
Let's now see what happens if we overprop. If we drop the continuous rpm by 20% (860rpm) then the power also drops by 20% to 12kW since torque is constant (134nm), and Vicprop gives a 19.2" x 13.9" prop. Peak power is still 26kW (290nm) so this happens at 1110rpm, cruising (3kW) is at 540rpm. Now we get:
 
Peak power : 26kW (190nm/660A) @ 1110rpm
Continuous : 12kW (134nm/304A) @ 860rpm
Cruising : 3kW (76A) @ 540rpm
 
So in exchange for 20% lower rpm the continuous power and current has also dropped by 20% to 12kW. The same is true for any amount of overpropping; you could drop rpm and power by 40% to end up with 9kW at 650rpm and a 21.5" x 17" prop. But all these numbers are defined by the continuous torque rating of the motor, in this case 134nm.
 
Now looking at your TEMA 132-12, the continuous torque rating is 111nm which at 1000rpm means 11.5kW, for this Vicprop suggests 17.3" x 11.7" -- almost exactly the same as for the Engiro (and Beta 43). Assuming the same peak/continuous torque ratio as the SPM132-1 (175/70=2.5:1) the peak torque for the SPM132-12 will be 276nm. Doing the same calculations as above, we get:
 
Peak power : 29kW (278nm) @ 1360rpm
Continuous : 11.5kW (111nm) @ 1000rpm
Cruising : 3kW @ 630rpm
 
So the maximum power for emergencies and rpm for cruising are very similar to the Engiro, but the continuous power *with a prop sized like this* is 23% lower -- this is because water cooling allows higher continuous powers, exactly as you said 🙂
 
If you now oversize the prop (as you have done) then power and rpm will both drop because torque is unchanged, just like the Engiro example above. Again using the Victron numbers (suggested prop size 18.2" x 12.9", equivalent to your 19" x 12"), we get the following:
 
Peak power : 25kW (278nm) @ 1170rpm
Continuous : 10kW (111nm) @ 860rpm
Cruising : 3kW @ 580rpm
 
This means you're about 14% overpropped with the 19" x 12" and the maximum continuous power/speed would be 10kW@860rpm,. which IIRC is what you found...
 
Going to 20" x 14", the Vicprop numbers for an equivalent 19.6" x 14.7" prop are:
 
Peak power : 21kW (278nm) @ 1050rpm
Continuous : 8.4kW (111nm) @ 730rpm
Cruising : 3kW @ 520rpm
 
So this is 27% overpropped compared to the "optimum" -- 27% lower power at 27% lower rpm.
 
The key point here is that overpropping reduces the power of the motor in exchange for lower rpm and lower noise. Your SPM132-12 would be 12kW continuous (TEMA headline rating) at 1040rpm, but as you drop the rpm (with bigger props) the power also drops -- 11.5kW/1000rpm with 17" x 12", 10kW/860rpm with 19" x 12", 8.4kW/730rpm with 20" x 14".
 
Again these numbers are the power that can be sustained for long enough for upstream travel on rivers, which is when high power is needed. For use on still canals -- cruising or in emergencies -- it's perfectly acceptable to overprop and get lower noise and lower rpm in exchange for lower sustained power.
 
I don't have the detailed numbers for the Bellmarine motor, but if it's rated at 15kW/1500rpm (which I think it is) this would give the following (again, from Vicprop).
 
Optimum prop size : 14.4" x 8.5" (equivalent to the 15" x 8" actually fitted):
Continuous power : 15kW @ 1500rpm
Cruising : 3kW @ 880rpm
 
These are *much* higher (+39%) rpm with a *much* smaller prop than either the Engiro or TEMA motors, because the Bellmarine motor is lower torque/higher rpm -- it's really too high for direct drive, the normal recommendation is to try and keep to not much over 1000rpm. It's one reason I rejected using this motor -- or any of the others running at this speed, or even faster (1800rpm) in some cases -- and why I chose the Engiro (as did Finesse, but theirs is a customized version). Prop noise increases rapidly with rpm due to increased turbulence, which is why a small high-speed prop isn't a good idea on a quiet low-speed boat like on the canals.
 
Overpropping with a bigger prop (like with the TEMA) would drop both rpm and noise but would also reduce the maximum power, if this is acceptable. If lower rpm/noise without this power loss in desired, then the Bellmarine motor would have to be replaced with one designed to run at lower rpm, such as the Engiro 12013 -- or the TEMA, though the continuous power of this is lower because of air cooling (which also makes more noise and dumps heat into the engine space instead of the canal).
 

I wouldn't like to vouch for the absolute accuracy of the Vicprop sizing down to this level of accuracy, there's a mention about only loading the engine to 90% but it's not clear how this affects the numbers -- but they do seem to be pretty close to real; life looking at various recommendations for prop sizing or what people have measured.

 

But the principles about how choosing/sizing/overpropping works with electric motors on canals are definitely correct:

 

-- if you want to get the maximum continuous power out of an electric motor for upstream river travel, match the prop size to the motor rating (continuous power/rpm)

-- water cooling both motor and controller will give more continuous power out of a given motor than air cooling, reduce motor noise, and keep the engine room cooler

-- if you're willing to accept lower power or don't anticipate ever using the boat upstream on rivers, overpropping will give lower rpm and noise than a matched prop

-- for a quiet electric boat with direct drive avoid motors with rated speed much above 1000rpm -- or overprop them to reduce rpm... 😉

 
Hope this helps people understand how all this electric motor/prop stuff works, because a lot of it is really *not* obvious or intuitive... 😉
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ENGIRO_Datasheet_205W_12013_ABC_V004(4).pdf 1.63 MB · 0 downloads

 

Over propping reduces the rotational speed at which peak power is achieved. OK.

I accept your characterisation of the desirability or otherwise for travelling upstream

Unfortunately my knowledge of aquanautics is non-existent so I have no idea how this affects reversing and manoeuvrability.

 

Pedant alert: A typical human eye will respond to wavelengths from about 380 to about 750 nanometers (excuse the American speeling).

Torque is normally expressed in newton metres; the correct symbol is Nm.

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20 minutes ago, George and Dragon said:

 

Over propping reduces the rotational speed at which peak power is achieved. OK.

I accept your characterisation of the desirability or otherwise for travelling upstream

Unfortunately my knowledge of aquanautics is non-existent so I have no idea how this affects reversing and manoeuvrability.

 

Pedant alert: A typical human eye will respond to wavelengths from about 380 to about 750 nanometers (excuse the American speeling).

Torque is normally expressed in newton metres; the correct symbol is Nm.

Especially with electric motors, overpropping also reduces power output, and by more than with diesel engines because the torque is flat where diesel engine torque rises as rpm falls below peak power.

 

There's no effect on manoeuvrability or stopping *so long as you use higher rpm*, power delivered into the prop is what matters -- in fact *if* you go up to maximum rpm an oversized prop will stop more slowly. People are reluctant to do this with diesels because of noise and vibration, hence the idea that a bigger prop gives better stopping power -- this comes down to "bollard pull" which is typically about a ton per 100hp regardless of prop size and rpm.

 

I blame autocorrect for nm vs. Nm -- should have spotted that, I work with nm every day... 😉

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Thanks Ian, that sort of info is going to become increasingly important to boaters over the next 15 years. 

If I remember the various threads here correctly, the ban on the use of IC engines comes into force in 2050, right? 

It is easy to imagine that, as an extra 'incentive', the tax on diesel and petrol will also increase in the intervening years. 

So although it seems very far away now, there will be thousands of boaters who will be giving more and more thought to electric propulsion over the next 15 years, since the value of diesel boats will start to fall away as 2050 approaches.  

There will probably be many boats that will become almost impossible to sell as 2050 approaches. A boat with a hull in poor condition. for example, might be seen as not worth the cost of an electric motor plus batteries installation, even with used items. 

It is to be hoped that by 2040 there will be lots of used electric vehicle motors becoming available, so that more boaters will be able to afford them, otherwise its easy to imagine that there will effectively be a huge cull of IC engined boats in 2050, leaving a fraction of the current number on the system. Yards up and down the country will be full of hauled out narrowboats awaiting electric installs that may never happen.  

Many of the boaters who are operating on tighter budgets will not be able to afford even used batteries and motor, so I guess we will see most of those being scrapped eventually.  

Installation of used electric motors could be set to be a booming canal business from 2040 onwards, one imagines. 

Recharging will hopefully get quicker too, and there will have to be a hell of a lot of infrastructure put in place to make it all practicable, otherwise there will be dozens of boats stranded every day by running out of battery charge- certainly during the winter months anyway. 

I reckon a boat full of solar could cruise for a few hours on every third day or so during the summer, just from the solar charge.

But in the winter, without a powerful onboard genny as a backup charger (ICE gennies will presumably also be banned), boats are going to need a certain minimum cruising range from their batteries, or else risk being stuck without motive power.

One imagines we might see many future boats with both sides and roof covered in panels.

Interesting times ahead. One feels we are approaching the end of an era, almost. 

 

 

Edited by Tony1
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47 minutes ago, Tony1 said:

 

Thanks Ian, that sort of info is going to become increasingly important to boaters over the next 15 years. 

If I remember the various threads here correctly, the ban on the use of IC engines comes into force in 2050, right? 

It is easy to imagine that, as an extra 'incentive', the tax on diesel and petrol will also increase in the intervening years. 

So although it seems very far away now, there will be thousands of boaters who will be giving more and more thought to electric propulsion over the next 15 years, since the value of diesel boats will start to fall away as 2050 approaches.  

There will probably be many boats that will become almost impossible to sell as 2050 approaches. A boat with a hull in poor condition. for example, might be seen as not worth the cost of an electric motor plus batteries installation, even with used items. 

It is to be hoped that by 2040 there will be lots of used electric vehicle motors becoming available, so that more boaters will be able to afford them, otherwise its easy to imagine that there will effectively be a huge cull of IC engined boats in 2050, leaving a fraction of the current number on the system. Yards up and down the country will be full of hauled out narrowboats awaiting electric installs that may never happen.  

Many of the boaters who are operating on tighter budgets will not be able to afford even used batteries and motor, so I guess we will see most of those being scrapped eventually.  

Installation of used electric motors could be set to be a booming canal business from 2040 onwards, one imagines. 

Recharging will hopefully get quicker too, and there will have to be a hell of a lot of infrastructure put in place to make it all practicable, otherwise there will be dozens of boats stranded every day by running out of battery charge- certainly during the winter months anyway. 

I reckon a boat full of solar could cruise for a few hours on every third day or so during the summer, just from the solar charge.

But in the winter, without a powerful onboard genny as a backup charger (ICE gennies will presumably also be banned), boats are going to need a certain minimum cruising range from their batteries, or else risk being stuck without motive power.

One imagines we might see many future boats with both sides and roof covered in panels.

Interesting times ahead. One feels we are approaching the end of an era, almost. 

 

 

The ban on IC engines is proposed but to actually make it happen -- without just replacing them with IC generators, which is what happens today -- charging points around the canal/river system will be needed, just like for EV on the roads. Today there is no sensible plan from CART and/or the government on how to make this happen, and not even a plan for a plan... 😞

 

The problem with EV electric motors for installation on boats -- especially DIY! -- is that they (and the batteries and controllers and chargers) use 400V DC, great for reducing wire size but a nightmare for safety and installation standards -- which is why car mechanics need special training and certification to be allowed to work on them. HV DC is essential for EV because of the huge power levels (>100kW) which make 48V DC impossible, this is not the case for boats which is why they're mostly 48V. It'll be interesting to see if/when boats switch over from LV DC to HV DC, I suspect it will happen eventually just because of the availability of kit but absolutely nobody is going that way today in the "small boat" world -- high-powered electric propulsion for things like ferries is already 400V or higher but they can put up with the HV problems.

 

I agree completely with your comments about solar; my power audit gave about 14kWh/day consumption for a typical full day of canal cruising, and solar (2kWp) would yield about 7kWh/day on average in summer. That's for a narrowboat with about 2/3 of the roof covered with panels, fitting more is difficult, and vertical panels on the sides don't give much power. The big problem is in winter, less than 2kWh/day won't get you very far, in fact probably nowhere once domestic 230Vac power consumption is added in... 😞

 

Even if the cost of a new electric installation becomes cheaper than diesel (which will happen, just like for EVs) the cost of ripping out a diesel and replacing it will still be high for some people as you say, they'll presumably just put this off until they have no choice. If they have to replace a dead diesel, they should be able to replace it with cheap secondhand electric by then -- but still likely to be more expensive to do... 😞

 

You're right, we are approaching the end of an era where cheap fossil fuel could be used to power even cheaper transport and provide heating, this applies to cars, motorbikes, trucks, trains, boats, ships, and houses (for heating). Change has to happen, and it will be more painful for some -- but the same applies to all aspects of lifestyle, climate change can't be ignored... 😉

 

16 minutes ago, Tonka said:

Shouldn't all of this been considered before the boat was built. What size prop will fit in where the prop shaft hole is under the counter

 

I'm confused about your question -- the problem isn't whether a bigger prop can be fitted in (it can), it's what effect that has on the motor power output...

Edited by IanD
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49 minutes ago, Tony1 said:

But in the winter, without a powerful onboard genny as a backup charger (ICE gennies will presumably also be banned), boats are going to need a certain minimum cruising range from their batteries, or else risk being stuck without motive power.

 

The plan is :

2025 - any boat built must be capable of being modifield to zero emission propulsion.

2035 - no boats can be built using non-zero emission propulsion

2050 - no boats on / in UK waters can be used with non-zero emission propulsion.

 

The use of on-board ICE powered generators will be allowed - it is the propulsion method that will be regulated, so :

 

Diesel to generator to battery to electric motor to gearbox to propellor will be fine up to, and beyond 2050

Edited by Alan de Enfield
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14 minutes ago, Alan de Enfield said:

 

The plan is :

2025 - any boat built must be capable of being modifield to zero emission propulsion.

2035 - no boats can be built using non-zero emission propulsion

2050 - no boats on / in UK waters can be used with non-zero emission propulsion.

 

The use of on-board ICE powered generators will be allowed - it is the propulsion method that will be regulated, so :

 

Diesel to generator to battery to electric motor to gearbox to propellor will be fine up to, and beyond 2050

 

I'm sure that's the case with the regulations as currently proposed, because they haven't been properly thought through.

 

It makes little "zero-emission" sense*** to replace a diesel engine driving a prop with a diesel engine driving a generator driving a motor driving a prop (which is certainly not "zero-emission propulsion"), and I'm sure when this is realised by the government the regulations will change. Diesel generators (and lawnmowers...) running from non-renewable fuel (does this *really* exist?) will presumably be banned too, just like burning fossil fuels for domestic heating will be. Everything has to change...

 

(*** yes I know that actually there is a CO2 reduction especially if you get some power from solar, I've provided figures several times, but not to "zero-emission"...)

Edited by IanD
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1 hour ago, IanD said:

 

I'm sure that's the case with the regulations as currently proposed, because they haven't been properly thought through.

 

It makes little "zero-emission" sense*** to replace a diesel engine driving a prop with a diesel engine driving a generator driving a motor driving a prop (which is certainly not "zero-emission propulsion"), and I'm sure when this is realised by the government the regulations will change. Diesel generators (and lawnmowers...) running from non-renewable fuel (does this *really* exist?) will presumably be banned too, just like burning fossil fuels for domestic heating will be. Everything has to change...

 

(*** yes I know that actually there is a CO2 reduction especially if you get some power from solar, I've provided figures several times, but not to "zero-emission"...)

 

I wonder if CRTs solution might be to license businesses to install charging points on the canal system?

It seems unlikely they will ever get enough govt funding to install the required charging points all over the system. There just aren't enough boats, and they are not important enough in any government's mind, to justify spending a lot of money on hundreds of charging points, often in rural locations.  Unless perhaps it gets done on the popular hire boat routes

If the charging points are run privately, one imagines the electricity will be expensive.  

 

Assuming ICE generators also get banned (or perhaps use only allowed for industrial purposes, or restricted by licence terms of some sort), then boaters have a real problem. 

Surely the level of income and business is just not present on the waterways to justify anyone spending on charging systems? 

Having to rely mostly on solar alone will make moving boats very much a rarity in the winter. 

 

I can only hope that, since there are only about 30,000 boats anyway, some sort of exemption is granted- either to continue using gennies, or ICE engines- at least until the charging infrastructure is in place.

I totally accept the critical need for reducing carbon emissions, as an almost existential threat to half of our species, and it does indeed require many changes that will upset many people's lifestyles- but it will nevertheless be a sad day if the canals are emptied of all narrowboats between Sept and April, save for a few hundred making short shuttles between a handful of very expensive charging points.

 

 

 

Edited by Tony1
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29 minutes ago, Tony1 said:

 

I wonder if CRTs solution might be to license businesses to install charging points on the canal system?

It seems unlikely they will ever get enough govt funding to install the required charging points all over the system. There just aren't enough boats, and they are not important enough in any government's mind, to justify spending a lot of money on hundreds of charging points, often in rural locations.  Unless perhaps it gets done on the popular hire boat routes

If the charging points are run privately, one imagines the electricity will be expensive.  

 

Assuming ICE generators also get banned (or perhaps use only allowed for industrial purposes, or restricted by licence terms of some sort), then boaters have a real problem. 

Surely the level of income and business is just not present on the waterways to justify anyone spending on charging systems? 

Having to rely mostly on solar alone will make moving boats very much a rarity in the winter. 

 

I can only hope that, since there are only about 30,000 boats anyway, some sort of exemption is granted- either to continue using gennies, or ICE engines- at least until the charging infrastructure is in place.

I totally accept the critical need for reducing carbon emissions, as an almost existential threat to half of our species, and it does indeed require many changes that will upset many people's lifestyles- but it will nevertheless be a sad day if the canals are emptied of all narrowboats between Sept and April, save for a few hundred making short shuttles between a handful of very expensive charging points.

 

 

There are plenty of possible ways to solve this problem with or without the involvement of the private sector, several have been suggested previously -- for example, since all EV charging points are privately installed, require them to put a tiny fraction (e.g. 1%-2%) of the money they spend on doing this into a "charging the canals" scheme. Would have no significant effect on the economics of EV charge points, but would provide the funds for them on the canals. It's estimated that EVs will need over half a million new charge points in the UK by 2035, 1%-2% of this is 5000-10000 which should be enough for the canals. But this needs will and joined-up thinking from the government (and CART) which seems sadly lacking... 😞

 

(please don't pick holes in the numbers, these are just "back-of-envelope" examples to demonstrate the principle!)

 

As in most other areas it's pretty much impossible to ban something (like ICE on the canals, or roads, or fossil-fuelled power stations) without having a "green" alternative in place -- until then exceptions are always made, no matter how ecologically undesirable this seems.

 

The cost of power from charging points would be higher than the wholesale rate (unless it's subsidised by the government which seems unlikely), but even at 2x this (70p/kWh at the moment) that's still about the same as running a boat on diesel, even ignoring solar power. If you do the same power audit I did, a full day's cruising would use about 9l of diesel for propulsion -- let's be optimistic and say this costs £10 -- as compared to 14kWh of leccy, which would also cost £10. In summer half this can easily be made up from solar, so the electric boat coats half as much -- in winter the difference is much smaller.

 

If you're depending entirely on shore power (no generator) then you also need a decent-sized battery bank to avoid having to charge up every day -- and don't forget domestic AC use too.

 

Yes there would have to be enough charging points close enough together and with enough in popular places to meet demand, but this is really not that much different to the EV charging problem -- except 1000x smaller (35k boats compared to 35M cars), so it's hardly unsolvable given the willpower and the money...

 

[all a bit off the original subject, but always comes up whenever electric boats are mentioned...]

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37 minutes ago, Tony1 said:

I can only hope that, since there are only about 30,000 boats anyway, some sort of exemption is granted- either to continue using gennies, or ICE engines- at least until the charging infrastructure is in place.

 

But that is only C&RTs share - there are some 90,000 boats registered in the Inland waterways - remember whilst C&RT may be one of the biggest Navigation Authorities, there are 26 more besides C&RT.

It is still a very small number of boats amortised against the huge cost of X.000 charger units and associated cabling and ground works.

 

There are also 250,000+ leisure boats around the coast, but, most of those will be in Marinas so an electrical supply (of some sort) should be available.

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13 minutes ago, Alan de Enfield said:

 

But that is only C&RTs share - there are some 90,000 boats registered in the Inland waterways - remember whilst C&RT may be one of the biggest Navigation Authorities, there are 26 more besides C&RT.

It is still a very small number of boats amortised against the huge cost of X.000 charger units and associated cabling and ground works.

 

There are also 250,000+ leisure boats around the coast, but, most of those will be in Marinas so an electrical supply (of some sort) should be available.

 

But we were talking about the canals and CART and charging points on the canal network. The other navigation authorities -- where you presumably are -- have the same problem and they also have to find a way to solve it.

 

Either way the size of the problem is not very big in absolute terms (e.g. compared to EV and green home heating), but is is compared to the number of boats -- if boaters had to pay for the charging points, it would undoubtedly cost (at least!) a four-figure sum per boat, similar to license fee cost for several years. You could say this isn't that bad compared to all the other costs, but it would be very difficult to find for poorer boaters, especially on top of any electric refitting costs.

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2 minutes ago, IanD said:

 

But we were talking about the canals and CART and charging points on the canal network. The other navigation authorities -- where you presumably are -- have the same problem and they also have to find a way to solve it.

 

Either way the size of the problem is not very big in absolute terms (e.g. compared to EV and green home heating), but is is compared to the number of boats -- if boaters had to pay for the charging points, it would undoubtedly cost (at least!) a four-figure sum per boat, similar to license fee cost for one (or more) years. You could say this isn't that bad compared to all the other costs, but it would be very difficult to find for poorer boaters, especially on top of any electric refitting costs.

 

 

I was responding to Tony assertion that because C&RT 'only' has 30,000 boats they could be allowed an exemption.

There are many others who could argue the same case for an exemption so where does it stop ?

 

Are you agreeing with Tony & also suggesting that C&RT (alone) should have an exemption , (or did you not actually read what was written) ?

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Just now, Alan de Enfield said:

 

 

I was responding to Tony assertion that because C&RT 'only' has 30,000 boats they could be allowed an exemption.

There are many others who could argue the same case for an exemption so where does it stop ?

 

Are you agreeing with Tony & also suggesting that C&RT (alone) should have an exemption , (or did you not actually read what was written) ?

 

No I read was was written, and I was not agreeing that the 30000 boats on CART waters should have an exemption -- *unless* there is no alternative provided, such as charging stations, which is what I said (did you read that?).

 

If the government wants to make cars green by banning diesels and switching everyone to EVs, they can't do this until there's a charging network available -- unless they ban cars entirely. The same applies to boats, regardless of whose waters they're on.

 

But I suspect you're about to say that's what they really want to do, and then close the canals down, so you moving off them proves you were right... 😉

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