IanD

Horses for courses. No way would I have a garden the size of my suburban one if I lived in Zone 1 or 2... 😉

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... 😉

I only quoted the London numbers because they're available for PM2.5 emissions. Some of us actually prefer to live here... 😉

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.

Death rates from smoking in London : 11000 per year Estimated death rates from PM2.5 emissions : <300 per year Number of deaths attributed to vaping since 2010 : 5 UK-wide ==> about 1 in London ==> <0.1 per year

Regardless of correctness (even in 'murica), it's what Thumper said in Bambi... 😉

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

The existing government is under pressure to reduce pollution from multiple sides, but since their mates live in Mayfair they may be reluctant to bring in a ban. The next government, not so much... 😉

Thumper was a rabbit in Bambi -- as I'd have thought most people would have known, not just @MtB's mum ! -- who said "If you can't say something nice, don't say nothing at all" 🙂

DEFRA approved stoves burning wood don't emit (much) smoke but do emit lots and *lots* of PM2.5 particles. The approval regulations were set before this was known. A ban on woodburning will affect all stoves, DEFRA approved or not.

Which of course they don't from woodburners... 😉

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

And your point is what?

What's going on is that the contribution of PM2.5 to respiratory disease and death was not known until recently. Yes it's always been there, but lots of other things contribute to such disease and deaths so the effects were hidden. It's also the case that the steep rise in urban woodburners (the dominant cause of the problem) is a recent fashion, previously people in towns burned coal -- which was of course banned when the risks due to that became known. On your principle anything risky that wasn't known about 100 years ago (or longer) should be allowed. Which is one reason why the Victorian life expectancy was lower than today and illness was much worse... 😞

It's not *incredibly* dangerous, it doesn't kill anything like as many people as cars, or alcohol, or tobacco, or many other things. But it is estimated to be responsible for a few hundred deaths per year in the UK and a lot more illness, as you'd know if you read the report. Most of the emissions are from "lifestyle" woodburners who can remove them as easily as they put them in, and those who need stoves (e.g. boaters) can burn smokeless fuel. So just like asbestos and lead and arsenic which the Victorians accepted because the risks weren't known, or DDT or thalidomide more recently, it's likely to be banned.

Nobody's talking about banning fuel burning heating systems -- at least, not in this case -- just stopping the burning of wood. Smokeless fuel is widely available, most stoves can burn it, and it emits far lower levels of PM2.5 than wood. I know you don't like reading numbers written by other people, but perhaps you should in this case, I posted a link in an earlier thread but a search should find it for you in a few seconds. Diesel fired heating emits fewer PM2.5 than smokeless fuel, and car tyres less than diesel engines in road vehicles -- and total PM2.5 emissions from UK transport (including from tyres) are 3x lower than from woodburners.

And some of them might turn into nice boaters and useful contributors to CWDF, if they're not put off by posts like yours... 😉 You don't have to be nice to them if you don't want to, but equally you don't have to make aggressive posts with no useful information or comment. Thumper had something to say about this. Hang on, I'm sure I already said that recently about another poster... 😞

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.