Proposed new accessible electric narrowboat.

[magnetman]

Wood pellets shipped from Canada to Yorkshire then burned in a power station are classed as renewable energy. 

6 minutes ago, Andrew Grainger said:

... am installing solar and batteries at our home which together is sufficient to cover all my electricity needs, home and boat, with some surplus solar to export. 

Is the Boat to be moored beside your house? That would be a good setup. 

 

 

[Andrew Grainger]

5 minutes ago, magnetman said:

Wood pellets shipped from Canada to Yorkshire then burned in a power station are classed as renewable energy. 

Is the Boat to be moored beside your house? That would be a good setup. 

 

 

I agree, DRAX is a scandal! No, 200 miles apart!

[IanD]

19 minutes ago, ditchcrawler said:

I think we all agree that ventilation is only advisory for the BSS but no matter how well matched, designed and specified it wont meet the BSS requirements as its powered and not free ventilation 

The BSS requirements for free-air ventilation on a gas-free boat with no stove (like mine) are tiny anyway, so mechanical heat recovery will save very little energy.

[magnetman]

Just now, IanD said:

The BSS requirements for free-air ventilation on a gas-free boat with no stove (like mine) are tiny anyway, so mechanical heat recovery will save very little energy.

Do they let you have enough air to breathe?

[IanD]

24 minutes ago, Andrew Grainger said:

Budget has yet to be established and is subject to the feasibility, that said I am realistic, this is not going to be cheap and it is possible it turns out to be simply uneconomic! 
Batteries will be costly but are getting cheaper all the time. 
As for grid power, some suppliers are much better than others eg Octopus. Also I have bought a  crowdfunded share of a large onshore wind farm and am installing solar and batteries at our home which together is sufficient to cover all my electricity needs, home and boat, with some surplus solar to export. 

 

The problem is that as soon as you're a day's cruise away from home you're going to need another source of power, and solar's unlikely to provide enough unless you hardly ever move -- my boat's got about the maximum amount of solar you can get on a narrowboat roof (2kWp) which is projected to yield an average of 7kWh/day in summer and maybe 1kWh/day in winter. On a 48' boat you'd be doing well to squeeze out 5kWh/day, which is probably just about enough to power everything on board including cooking, but with little or nothing left over for propulsion and certainly nothing for heating.

 

6 minutes ago, magnetman said:

Do they let you have enough air to breathe?

Of course, that's what the rules are there for... 😉

Edited December 18, 2023 by IanD

[Sailbadthesinner]

On 16/12/2023 at 22:53, Andrew Grainger said:

Thanks for all the comments, I am new to this forum.
To clarify, the proposal is a new build Narrowboat, c45ft length. With a permanent mooring with shore power when required. Part time live aboard, part time cruising, some extended cruises though minimal in winter months.
Objective is to fit out to standards as close as possible equivalent to pasivhaus for housing. 
So, all electric (engine, heating, cooking), high levels of insulation, MVHR with air filtration and dehumidifier, max solar PV. Accessibility for as we age. 
Examples, contacts, ideas all welcome thank you. 

To give you some idea of what can be done, my wife and I spend 6 months gentle cruising the waterways in our 25 ft grp cruiser with a 6kW motor, 15kWh battery and 1.2kW solar. We cook by electricity but have gas as a backup in cloudy weather. No generator, not felt the need for one. It would be different if we wanted to cruise outside these six months. For a narrowboat I reckon you could do similar if you doubled up on motor power, battery and added as much solar as possible.

You have shore power at your mooring so you could spend time aboard off season and take occasional day trips.

Just dont expect to race around the network all day every day!

 

[Up-Side-Down]

Going back to the OP's original question, I don't think anyone has mentioned this useful guide published by the IWA Sustainable Boating Group:

 

https://waterways.org.uk/wp-content/uploads/2023/08/An-Introduction-to-Electric-Narrowboating-Issue-1-1.pdf

 

[Andrew Grainger]

32 minutes ago, Up-Side-Down said:

Going back to the OP's original question, I don't think anyone has mentioned this useful guide published by the IWA Sustainable Boating Group:

 

https://waterways.org.uk/wp-content/uploads/2023/08/An-Introduction-to-Electric-Narrowboating-Issue-1-1.pdf

 

Thanks, I’d not seen that. 

[Up-Side-Down]

Lots of other useful, up to date, info on their site in relation to sustainable boating.

[Andrew Grainger]

11 minutes ago, Up-Side-Down said:

Lots of other useful, up to date, info on their site in relation to sustainable boating.

Yes thanks again, I have just seen and joined!

[Willonaboat]

1 hour ago, Up-Side-Down said:

Lots of other useful, up to date, info on their site in relation to sustainable boating.

 

I've voted your post up. Not because of your post but because of your signature. It made I larf 🤣

[IanD]

15 hours ago, Andrew Grainger said:

Thanks, I’d not seen that. 

There's a lot of really good information in there, but a couple of gotchas too...

 

The section about water-source heat-pumps (great for efficiency!) doesn't mention the problem of them not working at low water temperatures, which is when they are most needed (heating in winter).

 

The section on props is self-contradictory; it correctly points out that a direct-drive motor should really run at no more than 1000rpm (because faster ones need small props) and about how to correctly size props, but also says that electric motors can use "bigger more efficient props" because of their torque characteristics (high torque at low speed) which is basically wrong -- a prop at low speed needs very little torque to turn it, and any motor (diesel or electric) can produce far more than is needed.

[Andrew Grainger]

41 minutes ago, IanD said:

There's a lot of really good information in there, but a couple of gotchas too...

 

The section about water-source heat-pumps (great for efficiency!) doesn't mention the problem of them not working at low water temperatures, which is when they are most needed (heating in winter).

 

The section on props is self-contradictory; it correctly points out that a direct-drive motor should really run at no more than 1000rpm (because faster ones need small props) and about how to correctly size props, but also says that electric motors can use "bigger more efficient props" because of their torque characteristics (high torque at low speed) which is basically wrong -- a prop at low speed needs very little torque to turn it, and any motor (diesel or electric) can produce far more than is needed.

Thanks that’s good to know. 

[Up-Side-Down]

26 minutes ago, IanD said:

There's a lot of really good information in there, but a couple of gotchas too...

 

The section about water-source heat-pumps (great for efficiency!) doesn't mention the problem of them not working at low water temperatures, which is when they are most needed (heating in winter).

 

The section on props is self-contradictory; it correctly points out that a direct-drive motor should really run at no more than 1000rpm (because faster ones need small props) and about how to correctly size props, but also says that electric motors can use "bigger more efficient props" because of their torque characteristics (high torque at low speed) which is basically wrong -- a prop at low speed needs very little torque to turn it, and any motor (diesel or electric) can produce far more than is needed.

Both very good points.

 

In the first instance I guess Beacon Boats, who have a water-source heat pump in a hire boat, just are't hiring it out in the winter so the issue has not manifested itself.

 

Now that you've pointed it out, I can see the contradiction re prop sizing. I'm in the process of converting my narrowboat from diesel to electric drive, fortunately starting from the position of having the largest prop that can be swung between my skeg and uxter plate, with more pitch than you or I have had hot dinners! I'm looking at a nominally rated 15hp electric motor to turn it and have been debating between direct drive and gearing things down with a belt drive. In its previous incarnation that prop has never turned at more that 750 rpm and the boat usually cruises with it revolving at around 375 - 425 rpm. 

 

I'd got as far as recognising that 'a prop at low speeds needs very little torque to turn it' (hence the motor could 'at this point' be tiny, in theory) but what is happening with the motor requirements as you increase the prop speed? If I've got it right, torque is power times speed, therefore it's as the prop speed increases that the demand for horsepower increases, so in choosing a motor one is effectively legislating for output at maximum performance and it's here that the 15hp (or whatever) is actually required.

[IanD]

Just now, Up-Side-Down said:

Both very good points.

 

In the first instance I guess Beacon Boats, who have a water-source heat pump in a hire boat, just are't hiring it out in the winter so the issue has not manifested itself.

 

Now that you've pointed it out, I can see the contradiction re prop sizing. I'm in the process of converting my narrowboat from diesel to electric drive, fortunately starting from the position of having the largest prop that can be swung between my skeg and uxter plate, with more pitch than you or I have had hot dinners! I'm looking at a nominally rated 15hp electric motor to turn it and have been debating between direct drive and gearing things down with a belt drive. In its previous incarnation that prop has never turned at more that 750 rpm and the boat usually cruises with it revolving at around 375 - 425 rpm. 

 

I'd got as far as recognising that 'a prop at low speeds needs very little torque to turn it' (hence the motor could 'at this point' be tiny, in theory) but what is happening with the motor requirements as you increase the prop speed? If I've got it right, torque is power times speed, therefore it's as the prop speed increases that the demand for horsepower increases, so in choosing a motor one is effectively legislating for output at maximum performance and it's here that the 15hp (or whatever) is actually required.

 

That's correct, electric motor torque is roughly flat with speed (power is proportional to rpm) and prop torque is proportional to speed^2 (power proportional to rpm^3). So you have to choose what rpm/speed/torque you want these curves to cross, which could be either maximum continuous motor power/rpm (for best boat performance upstream on a river) or peak motor speed/power -- or you can deliberately overprop to keep the rpm down but at the cost of not being able to use the full power of the motor.

 

The majority of the motors which people are using in narrowboats are rated at around 1500rpm, because motors rated at 1000rpm or so put out less power and/or are bigger/heavier/more costly. These either end up needing a small prop (noisier "egg-whisk") or are overpropped which reduces motor power.

 

If you want to see how this works, have a play with the Vicprop calculator to get a feel for what happens -- the exact prop sizes may be a bit off (though they're pretty close in a lot of places) but you'll see the trends.

 

https://vicprop.com/displacement_size_new.php

 

For example, if I put in the numbers for my boat (15kW/20hp at 1080rpm) it predicts 6.46kts with a 17.4" x 11.6" prop. With overpropping (constant motor torque) this happens:

 

rpm     kW     kts     DxP

1080    15     6.46   17.4x11.6

900      12.5  6.08    18.8x13.3

720      10     5.64    20.5x15.6

540      7.5    5.12    23.0x19.3

[Up-Side-Down]

24 minutes ago, IanD said:

 

That's correct, electric motor torque is roughly flat with speed (power is proportional to rpm) and prop torque is proportional to speed^2 (power proportional to rpm^3). So you have to choose what rpm/speed/torque you want these curves to cross, which could be either maximum continuous motor power/rpm (for best boat performance upstream on a river) or peak motor speed/power -- or you can deliberately overprop to keep the rpm down but at the cost of not being able to use the full power of the motor.

 

The majority of the motors which people are using in narrowboats are rated at around 1500rpm, because motors rated at 1000rpm or so put out less power and/or are bigger/heavier/more costly. These either end up needing a small prop (noisier "egg-whisk") or are overpropped which reduces motor power.

 

If you want to see how this works, have a play with the Vicprop calculator to get a feel for what happens -- the exact prop sizes may be a bit off (though they're pretty close in a lot of places) but you'll see the trends.

 

https://vicprop.com/displacement_size_new.php

 

For example, if I put in the numbers for my boat (15kW/20hp at 1080rpm) it predicts 6.46kts with a 17.4" x 11.6" prop. With overpropping (constant motor torque) this happens:

 

rpm     kW     kts     DxP

1080    15     6.46   17.4x11.6

900      12.5  6.08    18.8x13.3

720      10     5.64    20.5x15.6

540      7.5    5.12    23.0x19.3

Once again, Ian, I'm indebted to you for your input.

 

My problem largely revolves around (pun intended!) a lifetime's involvement with the performance characteristics of ICE and I find I really struggle to get my head around the leccy equivalent. 

 

So, there isn't really a gearing need when dealing with this sort of rev range?? I guess it only becomes essential when looking at the sort of speeds that a Lynch DC motor revolves at, hence them selling units in a cradle with a choice, in most cases, of three different gearings.

[IanD]

17 minutes ago, Up-Side-Down said:

Once again, Ian, I'm indebted to you for your input.

 

My problem largely revolves around (pun intended!) a lifetime's involvement with the performance characteristics of ICE and I find I really struggle to get my head around the leccy equivalent. 

 

So, there isn't really a gearing need when dealing with this sort of rev range?? I guess it only becomes essential when looking at the sort of speeds that a Lynch DC motor revolves at, hence them selling units in a cradle with a choice, in most cases, of three different gearings.

So long as the motor you choose has high enough torque (warning: many don't!) you can always overprop so long as you don't mind giving up some power (and boat speed). Just be aware that most of the motors are rated at 1500rpm (or higher!) which *does* mean you end up with a small noisy egg-whisk, this was hinted at in the document... 😉

 

Gearing/toothed belt drive removes this problem, the downside is there can be more noise (whine from higher-speed motor and/or belt) and some risk of belt breakage if you get a sudden prop jam. Direct drive avoids this but you're back to the torque/power/rpm/prop size issue.

 

If you're choosing the motor yourself, for direct drive I'd suggest a low-speed PMAC one with a suitable controller, for example the Engiro 205W-12013 (15kW/1080rpm) with a Sevcon Gen4 size 6 48V controller.

 

https://www.voltsport.co.uk/Engiro-205W_12013

Edited December 19, 2023 by IanD

[Up-Side-Down]

20 minutes ago, IanD said:

So long as the motor you choose has high enough torque (warning: many don't!) you can always overprop so long as you don't mind giving up some power (and boat speed). Just be aware that most of the motors are rated at 1500rpm (or higher!) which *does* mean you end up with a small noisy egg-whisk.

 

Gearing/toothed belt drive removes this problem, the downside is there can be more noise (whine from higher-speed motor and/or belt) and some risk of belt breakage if you get a sudden prop jam. Direct drive avoids this but you're back to the torque/power/rpm/prop size issue.

 

If you're choosing the motor yourself, for direct drive I'd suggest a low-speed PMAC one with a suitable controller, for example the Engiro 205W-12013 (15kW/1080rpm) with a Sevcon Gen4 size 6 48V controller.

 

https://www.voltsport.co.uk/Engiro-205W_12013

Great! Thank you. You've mentioned this motor/controller combo before as I believe it's what you've specified for your boat. When I looked it up there is a note on the Engiro site to the effect that they don't sell to Joe Public, just into the trade. I guess you've found a way round this?

 

You've also explained my disappointment when I recently rode aboard a Lynch-powered boat: I was surprised by the lack of 'silent progress' I'd expected and very aware of the noise emitting from motor and drive. Not the shush, hush electric boating I was expecting!

 

To the OP, if this is all starting to get rather arcane and generally too eclectic for your taste, there is one very important takeaway from this discussion and that is that the majority of boat builders schooled in the technology and performance of the infernal combustion engine are (just like me) some way off getting their collective heads around all the ins and outs of electric drive. This means that there are, already, some disappointed customers out there who will have spent a lot of money commissioning their new electric pride and joy. I have met one or two of them.

 

From my own experience, back in the diesel-day, it was not uncommon to come across newly-built boats with the wrong size prop fitted. I certainly owned one before I got Crowther's involved. This will have happened both through ignorance and because it's much cheaper to fit a common, off-the-peg prop than something a bit 'rarer' and therefore more expensive and harder to source.

 

These two factors still very much prevail in the relatively virgin territory of electric boat building and while someone with the knowledge, experience and understanding of IanD makes it all look easy, he's currently very much in the minority as your reading on this forum will probably have already demonstrated to you. It's still very much a Caveat Emptor landscape out there where building electric boats is concerned. So you can't equip yourself with too much knowledge before embarking on a journey into this brave new, net zero world!!

[IanD]

8 minutes ago, Up-Side-Down said:

Great! Thank you. You've mentioned this motor/controller combo before as I believe it's what you've specified for your boat. When I looked it up there is a note on the Engiro site to the effect that they don't sell to Joe Public, just into the trade. I guess you've found a way round this?

 

You've also explained my disappointment when I recently rode aboard a Lynch-powered boat: I was surprised by the lack of 'silent progress' I'd expected and very aware of the noise emitting from motor and drive. Not the shush, hush electric boating I was expecting!

 

To the OP, if this is all starting to get rather arcane and generally too eclectic for your taste, there is one very important takeaway from this discussion and that is that the majority of boat builders schooled in the technology and performance of the infernal combustion engine are (just like me) some way off getting their collective heads around all the ins and outs of electric drive. This means that there are, already, some disappointed customers out there who will have spent a lot of money commissioning their new electric pride and joy. I have met one or two of them.

 

From my own experience, back in the diesel-day, it was not uncommon to come across newly-built boats with the wrong size prop fitted. I certainly owned one before I got Crowther's involved. This will have happened both through ignorance and because it's much cheaper to fit a common, off-the-peg prop than something a bit 'rarer' and therefore more expensive and harder to source.

 

These two factors still very much prevail in the relatively virgin territory of electric boat building and while someone with the knowledge, experience and understanding of IanD makes it all look easy, he's currently very much in the minority as your reading on this forum will probably have already demonstrated to you. It's still very much a Caveat Emptor landscape out there where building electric boats is concerned. So you can't equip yourself with too much knowledge before embarking on a journey into this brave new, net zero world!!

 

Finesse did my complete boat installation, they supplied the motor which I believe is a custom version of the Engiro 12013 to further optimise torque/rpm. The prop is a custom 4-blade from Michigan Marine, I wanted this for lower noise and vibration compared to a 3-blade and this seems to have worked -- but they didn't have any 4-blade blanks with the right diameter/pitch/boss/prop shaft size so it had to be specially machined down (including the boss) from a bigger one, yet more cost... 😞

 

https://mmp-i.com/leisure/canal/canal-line-propellers/

 

The motor and drive are pretty much inaudible at normal speeds, all you get is the gurgle from the prop wash. Flat out the wash is considerably noisier but the boat is still very quiet compared to a diesel, even with the generator running.

[magnetman]

How much was the Boat?
 

I mean total amount paid before it was floating and useable.

Edited December 19, 2023 by magnetman

[IanD]

15 minutes ago, magnetman said:

How much was the Boat?
 

I mean total amount paid before it was floating and useable.

 

The exact figure is between me and Finesse, and anyway it strongly depends on the build and fitout -- my comment that I'd be very surprised if the OPs 45' boat came in at under £200k is a clue, though... 😉

Edited December 19, 2023 by IanD

[magnetman]

Goodness.

 

[Willonaboat]

Further to IanD's excellent information, I would add that I have an Engiro 205W 12202 motor fitted in my widebeam. This is the larger version of IanD's. It was supplied by Lightning Craft as their DD20 motor package - full details here: https://lightningcraft.co.uk/ for anyone interested.

 

Edited December 19, 2023 by Willonaboat

[BoatinglifeupNorth]

21 hours ago, IanD said:

 

The exact figure is between me and Finesse, and anyway it strongly depends on the build and fitout -- my comment that I'd be very surprised if the OPs 45' boat came in at under £200k is a clue, though... 😉

 Obviously there are cheaper builders, but looking at the cost for a new electric boat, then taking in all the air filtration/pollution control measures and other things the OP has mentioned, as you say the cost could be heading £200K way,  On a 45ft boat that may get used now and then for a few days, is it a viable proposition financially?  I would say not. If the OP decides to sell after a year or so, who is going to buy a used second hand 45ft boat for £100K plus, I would say no-one. The boat is too small and too restrictive IMO. 

[IanD]

26 minutes ago, BoatinglifeupNorth said:

 Obviously there are cheaper builders, but looking at the cost for a new electric boat, then taking in all the air filtration/pollution control measures and other things the OP has mentioned, as you say the cost could be heading £200K way,  On a 45ft boat that may get used now and then for a few days, is it a viable proposition financially?  I would say not. If the OP decides to sell after a year or so, who is going to buy a used second hand 45ft boat for £100K plus, I would say no-one. The boat is too small and too restrictive IMO. 

A somewhat longer boat in the 57'-60' range won't cost much more since it still needs all the same equipment (just a bit more steel and fitout), will still be "go-anywhere", will have considerably more space inside (up to 50% extra), and will be much easier to resell if that ever becomes necessary. All the same applies even more to a full length boat (70'-72') except the "go-anywhere" (and maybe easier to resell?) bit... 😉

Edited December 20, 2023 by IanD