Proposed new accessible electric narrowboat.

[peterboat]

1 hour ago, Matt Wardman said:

 

Thanks for the reply.

 

I think the point about weight is interesting - especially on a thread for Low Energy Narrow Boats as afaics there are relatively few ways to reduce required propulsion energy.

 

In my head these seem to be reducing weight (and therefore draft / blocking ratio a little, but with stability implications), more streamlined or less draggy hulls, power train efficiency (from the motor to the propeller), and potentially reducing speed (a challenge when starting from an upper limit of 3mph).

 

A BMW i3 only weighs 1.385 tonnes and is relatively light - correct, but that is still double the weight of the first 4 seat hatchback I owned, which weighed 685kg, and the i3 battery is relatively small.

 

Moving up the size range, electric SUVs are headed towards 3 tonnes, and even a mid-size BEV Estate such as the MG5 is around 2 tonnes with a claimed range of ~200 miles.

 

My own full size diesel estate (Skoda Superb) is about 15% lighter than this.

 

An area deserving of more attention than it gets imo, especially as these can often go faster than most drivers (including me) are used to, and higher weight is linearly more energy to be dissipated in a collision which increases the consequences of error.

 

But I went a bit off topic for the thread, and have a number of areas relating to domestic energy consumption on an NB I am still reflecting on before offering an opinion - ventilation, windows, incidental heat gains and losses, and peak load for a few.
 

Its lighter than that in BEV form 1195 kilos, the Rex is your quote. Size wise its quite big, the wheel in each corner sorts it out nicely for interior room.

Boat wise a highbridge fiber glass narrowboat would get you lightweight and a boat shape under water.

[Up-Side-Down]

I believe this is worth more than a quick glance:

 

https://cadalcraft.co.uk/about/

[ditchcrawler]

14 minutes ago, Up-Side-Down said:

I believe this is worth more than a quick glance:

 

https://cadalcraft.co.uk/about/

Pretty pictures here Designs – Cadal Craft Ltd

She is due to be fitted with a Frigomar heat pump system and refrigeration and water heaters from Indel Webasto. 

[Ronaldo47]

Mr. Pedrick, ably assisted by his cat Ginger, who is usually remembered for his wacky inventions, did patent a method of reducing the drag of ships by blowing air out under the hull to provide a layer of bubbles between the hull and the water.  Not such a wacky idea perhaps, as I once saw this patent cited as prior art in the search report of a patent for just this sort of thing filed by a German company.  I do wonder if this technique is actually being used commercially, as the cruise ship we were on a decade ago seemed to have a strip of bubbles all along it between its hull and the sea, but possibly there is another explanation for the bubbles?

 

In a canal boat, even if it works,  I would think that the energy required to pump the air would probably be greater than any energy saved by drag reduction. 

[ditchcrawler]

4 minutes ago, Ronaldo47 said:

  I do wonder if this technique is actually being used commercially, as the cruise ship we were on a decade ago seemed to have a strip of bubbles all along it between its hull and the sea, but possibly there is another explanation for the bubbles?

 

In a canal boat, even if it works,  I would think that the energy required to pump the air would probably be greater than any energy saved by drag reduction. 

 Info here Shipping firms are blowing bubbles under their ships to reduce drag | New Scientist

[MtB]

Wasn't there a problem with ships sinking a decade or four ago, said ships sailing though areas with massive bubbles rising from the sea bed? When trying to float in bubbles, it doesn't really work as there is no buoyancy obviously, when one thinks about it.

 

 

 

 

 

[ditchcrawler]

1 minute ago, MtB said:

Wasn't there a problem with ships sinking a decade or four ago, said ships sailing though areas with massive bubbles rising from the sea bed? When trying to float in bubbles, it doesn't really work as there is no buoyancy obviously, when one thinks about it.

 

 

 

 

 

Bit or a risk with gas well blowouts I understand .

[magnetman]

Bermuda triangle. 

[IanD]

4 hours ago, ditchcrawler said:

Pretty pictures here Designs – Cadal Craft Ltd

She is due to be fitted with a Frigomar heat pump system and refrigeration and water heaters from Indel Webasto. 

I'd love to know how they've got the Frigomar heat pump to work in winter with a skin tank...

[magnetman]

 

 

Also water which has air pumped into it. I wouldn't recommend falling in the canal beside the CRT orifices at Little Venice. Or below a weir. 

 

Water is alright for floating in but air is not so comfortable. Water/air mix definitely not ideal. 

 

 

I do wonder if a risk assessment is carried out if air is deliberately introduced to the water and the canal bank is not fenced. 

Aeration at Little Venice. 

 

 

Well dodgy. If someone goes in there I think they are going to be in very serious trouble. 

Edited December 27, 2023 by magnetman
missing word

[Ronaldo47]

The air seems to be in the form of thousands of tiny bubbles and I understand is designed to break up the boundary layer between the hull and the non-bubbled water, making it more slippery.

Edited December 27, 2023 by Ronaldo47
typo

[ditchcrawler]

9 minutes ago, magnetman said:

 

 

Also water which has air pumped into it. I wouldn't recommend falling in the canal beside the CRT orifices at Little Venice. Or below a weir. 

 

Water is alright for floating in but not so comfortable. Water/air mix definitely not ideal. 

 

 

I do wonder if a risk assessment is carried out if air is deliberately introduced to the water and the canal bank is not fenced. 

Aeration at Little Venice. 

 

 

Well dodgy. If someone goes in there I think they are going to be in very serious trouble. 

They use to pump air into the canal under the bridge by the Folly at Napton.

[MtB]

15 minutes ago, ditchcrawler said:

They use to pump air into the canal under the bridge by the Folly at Napton.

 

Why?

 

 

[magnetman]

Fish?

[MtB]

31 minutes ago, magnetman said:

Bermuda triangle. 

 

Oh a Barry Manilow fan!

 

 

1 minute ago, magnetman said:

Fish?

 

Oh a Marillion fan! 

 

 

 

[Rishworth_Bridge]

I have come rather late to this discussion but should like to offer a few thoughts, some based on 8 years' experience, some more blue sky. I should appreciate input from members who might have more detailed knowledge than I. As I haven't read the whole thread I apologise if I am re-covering ground already covered.

1. I don't believe that any boat doing more than token cruising can be 'carbon based fuels free' at this point in time. My approach favours incremental improvement so I'm happy to retain my diesel generator, taking steps to minimise its use while waiting for the day when I can take another tanker delivery of HVO. (We managed one in 2020, shortly before Crown realised the complexities of the then subsidy/tax situation.)

2. When trying to assess your power requirements don't believe the fanciful claims made by people wanting to sell boats with large solar arrays. Assume that you will need 1 kWh/mile for cruising (it will probably be a bit less) and add in your domestic requirements (fairly straightforward). Then see if it adds up, remembering that, unless you spend a lot of time tilting and pointing your panels, you will get a maximum of 50% of their nominal output in the UK, something often forgotten (conveniently ignored?) by solar advocates.

3. Having said that, power from rigid panels works out considerably cheaper than that from a diesel generator so is worth having on the basis of 'every little helps'. Power from flexible panels tends to be more expensive than diesel.

4. Our experience, and that of other longer-term users, is that (semi-)flexible panels are damaged by heat so are not very durable. Ours died after about 3 years and there are lots of reports on the Internet of others not lasting more than 5. Most of their most vocal defenders haven't even got 3 years experience yet. If you must use flexible panels try to arrange some sort of cooling, possibly using the hybrid panels now becoming available to allow you to circulate cooling water.

5. There can be little doubt that a water-source heat pump will be more efficient than an air-source one, though I would hesitate even to try to calculate how large the skin tanks to support one would need to be.
6. Years ago, when radiant electric ceiling heating was popular for the bedrooms of new-build houses with electric underfloor heating downstairs, I did some development work on it. Our findings then, seemingly still accepted, were that the system needed 20-25% less energy to provide comparable comfort. (For anyone unfamiliar with such systems, this is because the radiant heat keeps people warm while the air temperature remains lower than in a convection-based system so losses are less.) Nobody would consider using direct electric ceiling heating on a narrowboat but wet systems, using 'capillary matting' are readily available and will run happily on the sort of 30-40 degree output temperatures at which heat pumps work best. We have underfloor heating (using waste heat from our generator) in our boat but, like most boats, the floor area is relatively small so 500W is about the most we can obtain. However, the ceiling area is 3-4 times as large, giving the potential for up to 2 kW, probably, given the higher efficiency, enough to provide comfort in all but the most extreme weather. With a bit of luck a water-source pump would give about 400% efficiency so the power requirement would be more like 0.5 kW than the 1 kW previously suggested. The only problem I can foresee is that ceiling heating works best if the ceiling is a bit higher than is usual in a narrowboat, a minimum of 2.25m often being suggested. Maybe OK for vertically challenged boaters with Tyler-Wilson shells but not so good for my 6'2" in a Roger Farringdon!
7. Capturing waste heat from showers, sinks - and even loos - might be possible, if a bit complex.
8. The subject of double glazing has come up a few times. We started with typical, thin (12mm) panels, upgraded those to 18mm and then again to what are called 'warm edge' units (again 18mm). As most of the heat lost through double-glazed panels is at the edges and, given the small size of boat windows, there is a lot of 'edge', these were a big improvement - until they started to fail. We only have 8 or 9 (of 22) still sound after 3½ years (and that after 3 were replaced under warranty). Without going into detail, the problem arises from where and how the desiccant is stored. Not sure if this failure rate is normal or whether our local glass company just buys from a particularly careless manufacturer. The one panel which came from another manufacturer is one of those which is still OK but that's hardly statistically significant.

Over to you.

[peterboat]

16 minutes ago, Rishworth_Bridge said:

I have come rather late to this discussion but should like to offer a few thoughts, some based on 8 years' experience, some more blue sky. I should appreciate input from members who might have more detailed knowledge than I. As I haven't read the whole thread I apologise if I am re-covering ground already covered.

1. I don't believe that any boat doing more than token cruising can be 'carbon based fuels free' at this point in time. My approach favours incremental improvement so I'm happy to retain my diesel generator, taking steps to minimise its use while waiting for the day when I can take another tanker delivery of HVO. (We managed one in 2020, shortly before Crown realised the complexities of the then subsidy/tax situation.)

2. When trying to assess your power requirements don't believe the fanciful claims made by people wanting to sell boats with large solar arrays. Assume that you will need 1 kWh/mile for cruising (it will probably be a bit less) and add in your domestic requirements (fairly straightforward). Then see if it adds up, remembering that, unless you spend a lot of time tilting and pointing your panels, you will get a maximum of 50% of their nominal output in the UK, something often forgotten (conveniently ignored?) by solar advocates.

3. Having said that, power from rigid panels works out considerably cheaper than that from a diesel generator so is worth having on the basis of 'every little helps'. Power from flexible panels tends to be more expensive than diesel.

4. Our experience, and that of other longer-term users, is that (semi-)flexible panels are damaged by heat so are not very durable. Ours died after about 3 years and there are lots of reports on the Internet of others not lasting more than 5. Most of their most vocal defenders haven't even got 3 years experience yet. If you must use flexible panels try to arrange some sort of cooling, possibly using the hybrid panels now becoming available to allow you to circulate cooling water.

5. There can be little doubt that a water-source heat pump will be more efficient than an air-source one, though I would hesitate even to try to calculate how large the skin tanks to support one would need to be.
6. Years ago, when radiant electric ceiling heating was popular for the bedrooms of new-build houses with electric underfloor heating downstairs, I did some development work on it. Our findings then, seemingly still accepted, were that the system needed 20-25% less energy to provide comparable comfort. (For anyone unfamiliar with such systems, this is because the radiant heat keeps people warm while the air temperature remains lower than in a convection-based system so losses are less.) Nobody would consider using direct electric ceiling heating on a narrowboat but wet systems, using 'capillary matting' are readily available and will run happily on the sort of 30-40 degree output temperatures at which heat pumps work best. We have underfloor heating (using waste heat from our generator) in our boat but, like most boats, the floor area is relatively small so 500W is about the most we can obtain. However, the ceiling area is 3-4 times as large, giving the potential for up to 2 kW, probably, given the higher efficiency, enough to provide comfort in all but the most extreme weather. With a bit of luck a water-source pump would give about 400% efficiency so the power requirement would be more like 0.5 kW than the 1 kW previously suggested. The only problem I can foresee is that ceiling heating works best if the ceiling is a bit higher than is usual in a narrowboat, a minimum of 2.25m often being suggested. Maybe OK for vertically challenged boaters with Tyler-Wilson shells but not so good for my 6'2" in a Roger Farringdon!
7. Capturing waste heat from showers, sinks - and even loos - might be possible, if a bit complex.
8. The subject of double glazing has come up a few times. We started with typical, thin (12mm) panels, upgraded those to 18mm and then again to what are called 'warm edge' units (again 18mm). As most of the heat lost through double-glazed panels is at the edges and, given the small size of boat windows, there is a lot of 'edge', these were a big improvement - until they started to fail. We only have 8 or 9 (of 22) still sound after 3½ years (and that after 3 were replaced under warranty). Without going into detail, the problem arises from where and how the desiccant is stored. Not sure if this failure rate is normal or whether our local glass company just buys from a particularly careless manufacturer. The one panel which came from another manufacturer is one of those which is still OK but that's hardly statistically significant.

Over to you.

As I am a widebeam with 5 kws of solar summer cruising on solar is doable, I run the generator every other day for hot water. If I run the generator long enough it powers the over 5 kws of radiators as well.

I must have bought the HVO from crown at the same time as yourself as it was very cheap, I won't be buying it again as it's not renewable, its partly from palm oil sourced via Singapore, indigenous people and animals are losing their homes for cheap air flights on supposedly sustainable fuel hint it's not. Previously I used real biodiesel which now goes to the fossil fuel industries as the bio additive. I think its easier with a big boat than a narrowboat to go the solar way, with new panels I could install more solar on the roof, possibly 7 kws?

Many years ago I met a boat that had underfloor heating running from the engine it was lovely and warm, it was pipes running in concrete sitting in insulation so no contact with the base plate. 

[magnetman]

Maybe one day we can get diesel from sewage sludge. 

 

www.researchgate.net/publication/310612465_Bio-oil_production_from_dry_sewage_sludge_by_fast_pyrolysis_in_an_electrically-heated_fluidized_bed_reactor

 

 

[Rishworth_Bridge]

I understand that the provenance of the HVO currently sold in the UK is sound - waste oils and fats, etc. I share your concerns about potential conflict with food supplies if/as demand increases.

[peterboat]

10 minutes ago, Rishworth_Bridge said:

I understand that the provenance of the HVO currently sold in the UK is sound - waste oils and fats, etc. I share your concerns about potential conflict with food supplies if/as demand increases.

Crown bought from the Finnish company that has a HQ in Singapore so I am not so sure, the EU allows palm oil as a feedstock someone was saying on here.

[IanD]

2 hours ago, peterboat said:

As I am a widebeam with 5 kws of solar summer cruising on solar is doable, I run the generator every other day for hot water. If I run the generator long enough it powers the over 5 kws of radiators as well.

I must have bought the HVO from crown at the same time as yourself as it was very cheap, I won't be buying it again as it's not renewable, its partly from palm oil sourced via Singapore, indigenous people and animals are losing their homes for cheap air flights on supposedly sustainable fuel hint it's not. Previously I used real biodiesel which now goes to the fossil fuel industries as the bio additive. I think its easier with a big boat than a narrowboat to go the solar way, with new panels I could install more solar on the roof, possibly 7 kws?

Many years ago I met a boat that had underfloor heating running from the engine it was lovely and warm, it was pipes running in concrete sitting in insulation so no contact with the base plate. 

Even with a widebeam (5kWp of panels will give about 17kWh/day average in summer) I doubt that solar alone will keep up with several long days of cruising in a row as well as domestic power use -- I believe you rarely do this but other people do.

 

On a narrowboat (2kWp of panels?) there's no chance even in summer unless you go everywhere at "tickover" speed using about 1kW (0.5kWh/mile) which is what some optimistic electric boat promoters seem to assume -- for most people about 3kW (1kWh/mile at 3mph) when cruising along is much more realistic, as posted above. Even then, unless you do short days and/or moor up for a day in between them, solar won't keep up with propulsion and domestic demand except on really sunny days.

 

To give a speed/power benchmark for electric drive against a typical narrowboat diesel (Beta 43 with 2:1 gearbox and 18"x12" prop) 1kW would be about 900rpm ("tickover" past moored boats), 3kW would be about 1300rpm ("normal" cruising speed).

 

The issue with heat pumps is where the power to run them comes from. Obviously if you're plugged in to shoreline in a marina this is a great solution, but if you're cruising around and need heat (in winter) or cooling (in summer) the additional electrical load (kW/day) will be quite high because they have to run for a lot of hours per day. If this doesn't come from solar (unlikely while cruising or in winter) then it has to come from an onboard generator -- and then you might as well burn the fuel in a diesel boiler, if anything this is more efficient than (generator+heat pump) especially for air-source.

Edited December 28, 2023 by IanD

[Alan de Enfield]

11 minutes ago, IanD said:

The issue with heat pumps is where the power to run them comes from. Obviously if you're plugged in to shoreline in a marina this is a great solution, but if you're cruising around and need heat (in winter) or cooling (in summer) the additional electrical load (kW/day) will be quite high because they have to run for a lot of hours per day. If this doesn't come from solar (unlikely while cruising or in winter) then it has to come from an onboard generator -- and then you might as well burn the fuel in a diesel boiler, if anything this is more efficient than (generator+heat pump) especially for air-source.

 

You can just plug in a couple of oil-filled radiators (or other electric heaters of your choice)

[Up-Side-Down]

I can't help feeling that solar-powered cruising and the prevailing stoppage regime will prove to be highly compatible ...

[IanD]

9 minutes ago, Alan de Enfield said:

 

You can just plug in a couple of oil-filled radiators (or other electric heaters of your choice)

Which consume far more (expensive!) electricity than a heat pump -- OK for frost protection, not so good for heating when you're onboard, 4kW typically costs about £1 an hour.

[Rishworth_Bridge]

... and flattens your battery alarmingly fast! It's more than you would use for cruising. If the weather isn't excessively cold we often run a couple of fan heaters in the morning instead of lighting our oil stove but do so at the same time as running the generator to avoid charging losses.