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Electric Boats


peterboat

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6 minutes ago, Thames Bhaji said:

I’m thinking about this because a) diesel is so expensive now and b) most people seem to want to be greener, even if they don’t agree on the best way to do it. But unless I’m missing something, couldn’t cruising a bit slower halve both a boater’s fuel costs and carbon footprint?

Most boats use between 1.0 and 1.5 litres per hour, my own Beta 43 habitually around the 1.2 mark. I suggest were in the area of diminishing returns here, even at well over £1 per litre, certainly in trying to cut costs further by changing the power plant. However, 3 mph cruising is probably why I see 1.2lph.  With a displacement narrowboat hull, particularly in the shallow water on canals, every incremental increase in speed has a disproportionately ruinous effect on fuel consumption. Add that to the effect of the wake on the environment and the number of poorly moored boaters shouting at you to slow down, being more cognisant of cruising speed is a win-win-win situation.

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12 hours ago, peterboat said:

I am going to Castleford on Monday, single handed through those big locks is a challenge especially with a dodgy knee and elbow. I expect to cruise 3 hours daily which is enough for me. 

I expect to get to castleford in a couple of weeks which is quick enough for a holiday, I have stuff to do onboard which will take a couple of hours daily and I have a puppy to walk twice a day. Will I need my genny I have no idea? But I will probably run it to heat water for a shower every other day as well as powering the washer/dishwasher and 2 chargers how long? Under an hour gets me hot water easy enough. Once there its blacking and other work for a week in the dry dock happy days 🤣🤣🤣

CASTLEFORD for a holiday!! :o If you dropped an atom bomb on Cas it would do fifty pence worth of damage!!

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8 minutes ago, Sea Dog said:

being more cognisant of cruising speed is a win-win-win situation.


That’s what I’d have thought. I’m aware of the Environment Agency raising the issue of wash damage as a reason to keep speed down (CRT may do too but I’m only on the Thames). But if reducing speed also has a dramatic effect on fuel consumption (and subsequent cost to both boater and planet) then this seems ripe for an awareness campaign IMO. A sign at each lock with a simple (fact-checked) fact about x speed drop giving x reduction in fuel and carbon? I bet a lot of boaters don’t realise, and it wouldn’t take many to slow down a bit to make a difference. 

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37 minutes ago, peterboat said:

I built my system myself it wasn't hard or expensive, the genny is a late addition bought with 4 hours on the clock hopefully it will hardly be used as I would like my HVO to last until I give up boating.  Savings don't just stop at diesel, servicing and 25% reduced license all add up rapidly. My system including the genny cost less than a engine gearbox for the boat. Solar is extra but was so cheap why wouldn't you have it? Especially in summer when the drive solar heats water when not moving 

That was exactly why I wrote: "unless you buy everything pre-used and are competent to design and install everything yourself"

 

You are too modest, you are in a tiny minority of the boating fraternity who would think about designing, obtaining second hand and installing an electric system from scratch.

 

You compare the cost of your second hand electric setup to the price of a brand new diesel engine and gearbox which isn't really fair. If you want to go second hand, you need to compare your electric installation to a used diesel of which there are dozens available, in great condition, and with a very long life ahead of them for a few hundred pounds. Like for like I'm sure the diesel direct drive wins on price and you can travel at 4mph all day and more on rivers where the speed limit permits.

 

I say again, a slightly higher fuel bill for a diesel boat over an electric boat for a  few weeks of summer cruising is such a tiny proportion of the cost of ownership of a narrowboat that it's hardly significant.

 

 

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31 minutes ago, Thames Bhaji said:

This is a general observation / question, not in response to any particular post. 

 

I’ve seen quite a lot of discussion about how the efficiency of electric boats varies with speed. There is debate about the exact figures, but is generally agreed that a small change in speed (eg from 3 to 4 mph) makes a big difference in power needed (not far off double?). 

I haven’t seen much discussion about this in regards to conventional boats. If the above it true for electric drive, presumably the same difference in speed with a diesel drive will result in a roughly similar jump in fuel consumption?

 

I’m thinking about this because a) diesel is so expensive now and b) most people seem to want to be greener, even if they don’t agree on the best way to do it. But unless I’m missing something, couldn’t cruising a bit slower halve both a boater’s fuel costs and carbon footprint?

 

As this is an inland forum we need to consider three things.

The energy used in:

 

1. wave making

2. overcoming hull friction

3. pushing water up in front of the boat because of severely restricted  waterways.

 

Add to that the energy wasted when you try to drive a displacement boat at above its hull design  speed

 

All three increase with speed and some increase to the square of speed so a small reduction in speed can make a larger difference to fuel consumption.

 

It is unlikely that a typical narrow boat will have enough installed power to reach its hull design speed but at higher speeds you can see how the stern dips, so you are trying to drive the boat go uphill. This effect will become worse the more restricted the waterway.

 

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16 hours ago, IanD said:

If you take the boat I'm having built as an example, it will run at full power (15kW/20hp) for something over 2 hours without running the generator (or allowing for any solar) -- and though 3kW is "normal cruising power" on a still canal,

Given these figures, perhaps one answer is to reverse the trend towards ever bigger diesel engines.

 

I suspect that a 20hp diesel engine pushing a boat at 3mph might we'll only require 4hp of its maximum. If one then compares the cost of diesel consumed with the cost of running an electric boat, the difference would be even smaller.

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12 hours ago, Bargebuilder said:

Sure, there are plenty of noisy diesels out there, but some of them are wonderfully quiet. Of course not as silent as may be possible with electric, but a gentle 'purrrrr' that is not intrusive at all.

 

Electric will give you a slightly quieter experience than with a well silenced direct diesel driven NB and it may save on fuel consumption, but unless you buy everything pre-used and are competent to design and install everything yourself, how much more will it cost than a simple diesel driven boat? 

 

How does the price of a cocooned super silent diesel generator compare to that of a propulsion diesel engine?

 

That aside, the main reason why I wouldn't consider an electric narrowboat is the thought of having to go slowly everywhere. People who can only manage a few weeks each year on their boat and who want to experience as much of the canal network as possible during that time, want to travel at 4mph when it's appropriate to do so and over a months motoring, any saving made by going electric would be inconsequential when compared to the other costs of ownership.

 

For people with deep pockets who spend most of the year aboard and have the time to pootle slowly and silently everywhere I can see the attraction, but that's not me I'm afraid.

 

I really don't understand where you're getting the idea from that (properly designed) electric/series hybrid boats are slow...

 

15kW/20hp is what a Beta 43 (into a matched prop) puts out at 2200rpm, which is an engine speed I suspect very few narrowboats ever cruise at -- even on rivers -- since it makes big waves and plenty of noise and vibration to boot.

 

As I've said many times, a hybrid boat makes no *financial* sense because the fuel savings are swamped by the much higher installation cost, largely due to the generator. Right now it's a luxury purchase for people with deep pockets who are willing to pay a premium to have a much nicer boating experience, it probably adds about 15% to the cost of a new high-end boat which is less than the cost adder for such a boat over lower-quality ones from less reputable builders.

 

If they're also concerned about being "green" then there is a big CO2 saving, maybe 50% if you cruise for long hours every day, 100% in summer of you cruise much less and can rely on solar.

 

This will only change (and make financial sense for most people) in the distant future when the cost of batteries has dropped further and charging points mean the generator isn't needed -- exactly the same position as for BEV vs. hybrid cars.

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I remember reading some years ago that the optimum speed in a canal is the speed of a wave in the canal. Travelling at the same speed as your bow wave results in a sort of resonance where you effectively surf your bow wave. I don't know if this is strictly correct, but have used this as a rule of thumb unless circumstances dictate otherwise, such as where there is a very strong cross-wind needing high revs to stop getting blown into the bank. 

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17 minutes ago, Bargebuilder said:

Given these figures, perhaps one answer is to reverse the trend towards ever bigger diesel engines.

 

I suspect that a 20hp diesel engine pushing a boat at 3mph might we'll only require 4hp of its maximum. If one then compares the cost of diesel consumed with the cost of running an electric boat, the difference would be even smaller.

 

The real reason such big engines are installed is probably because -- unlike the old low-speed traditional engines -- they don't like running close to maximum rpm/power all the time, so oversizing them keep wear/noise/vibration down. As you say typical canal cruising uses about 3kW/4hp (this is backed up by lots of measurement data), you only need a lot more than this in emergencies or on fast-flowing rivers. A Beta 43 (42hp/2800rpm) will typically cruise around 1400rpm (3hp), and is unlikely to ever run faster than 2200rpm (20hp) even on rivers -- which non-coincidentally is what a lot of the trad engines put out, and there were never seen as underpowered.

 

There's also the "market expectation" -- everyone expects engine sizes to follow the manufacturer's recommendations, so any boat with a smaller engine is seen as "underpowered" even if it isn't really...

 

The biggest fuel savings with a hybrid boat are not just from the higher efficiency but also even bigger savings when going more slowly past moored boats and when stationary in locks, this is where the ~50% fuel saving comes from even ignoring solar. This isn't justified by cost (given the higher boat cost) but it is greener, especially if you cruise less (a few hours per day) when at least in summer solar can provide all the power needed.

 

(but not with heavy cruising or in winter, which is why an expensive generator is needed).

1 minute ago, Ronaldo47 said:

I remember reading some years ago that the optimum speed in a canal is the speed of a wave in the canal. Travelling at the same speed as your bow wave results in a sort of resonance where you effectively surf your bow wave. I don't know if this is strictly correct, but have used this as a rule of thumb unless circumstances dictate otherwise, such as where there is a very strong cross-wind needing high revs to stop getting blown into the bank. 

 

It's not really correct, a canal boat is not a bulk carrier -- power always increases rapidly (at least cube law) with speed, and even faster when you start to make a breaking wash -- which is really what limits speed on canals.

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4 minutes ago, Ronaldo47 said:

I remember reading some years ago that the optimum speed in a canal is the speed of a wave in the canal. Travelling at the same speed as your bow wave results in a sort of resonance where you effectively surf your bow wave. I don't know if this is strictly correct, but have used this as a rule of thumb unless circumstances dictate otherwise, such as where there is a very strong cross-wind needing high revs to stop getting blown into the bank. 

Soliton wave effect. 

 

They did experiments years ago with high speed horse drawn boats but it does need a sensibly shaped channel. A good breakfast bowl shape would probably be okay but a saucer shape is not all that useful. 

 

 

ETA mentioned in this Fred 

 

 

Edited by magnetman
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5 minutes ago, magnetman said:

Soliton wave effect. 

 

They did experiments years ago with high speed horse drawn boats but it does need a sensibly shaped channel. A good breakfast bowl shape would probably be okay but a saucer shape is not all that useful. 

 

 

ETA mentioned in this Fred 

 

 

 

Also note how damn fast you have to travel, even if you can make the soliton wave happen -- *way* faster than 4mph... 😉

Edited by IanD
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2 minutes ago, magnetman said:

Indeed. Slightly annoying for anyone tied up ! 

 

Must be pretty wicked doing 9mph on a narrow boat though. 

Also needs a hull which is narrower and has shallower draught and much finer lines than any narrowboat -- otherwise there's no chance of getting it up to the speed where the soliton effect happens...

 

I've done well over 9mph in a big-engined (Bolinder 1043) trad boat (Kate Snow's "Baron", downstream on the River Lea at 2am... 😉

Edited by IanD
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59 minutes ago, Bargebuilder said:

 

 

I say again, a slightly higher fuel bill for a diesel boat over an electric boat for a  few weeks of summer cruising is such a tiny proportion of the cost of ownership of a narrowboat that it's hardly significant.

 

 

You are not wrong but for many it isn't about that.  It is about silent cruising for one thing so I think you are comparing apples to oranges.

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6 minutes ago, PD1964 said:

Even tick over is annoying to some malnourished looking boaters, living on wrecks, moored right next to bridge holes on the North Oxford. 

On the western part of the K&A a couple of weeks ago I had spent at least 30 mins on tick over because of the huge numbers of boats moored up and as I went past one broad beam I was asked to slow down! I told her that I was on tick over and maybe she should put a spring on it. Wow, the fuse was lit, she then suggested I put into N. She can fcuk off.  I am amazed that even boats on permanent moorings don't put a spring on the lines.  So much better.  

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1 hour ago, IanD said:

Also needs a hull which is narrower and has shallower draught and much finer lines than any narrowboat -- otherwise there's no chance of getting it up to the speed where the soliton effect happens...

 

I've done well over 9mph in a big-engined (Bolinder 1043) trad boat (Kate Snow's "Baron", downstream on the River Lea at 2am... 😉

I thought Baron belonged to Pete Wakeham at Denham. Josher with 3 pot Bolinders engine. 

 

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1 hour ago, Markblox said:

On the western part of the K&A a couple of weeks ago I had spent at least 30 mins on tick over because of the huge numbers of boats moored up and as I went past one broad beam I was asked to slow down! I told her that I was on tick over and maybe she should put a spring on it. Wow, the fuse was lit, she then suggested I put into N. She can fcuk off.  I am amazed that even boats on permanent moorings don't put a spring on the lines.  So much better.  

Lots of parts of the system have the same problem, Nantwich and Braunston come to mind from recent trips. I had exactly the same complaint and gave exactly the same response a couple of weeks ago... 😞

 

Lots of boats don't know how to moor properly (especially using spikes) even without springs, and wouldn't know what one was if you hung them with it -- they use single lines almost at right-angles to the bank with single spikes, and then they wonder why these get pulled out as the boat is pulled backwards and forwards by boats passing at tickover...

 

It doesn't help that few canal boats have spring line fixings, so you need four spikes (or eight if doubled) and people don't bother.

Edited by IanD
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1 minute ago, IanD said:

 - they use single lines almost at right-angles to the bank with single spikes, and then they wonder why these get pulled out as the boat is pulled backwards and forwards by boats passing at tickover...

And so much slack it dangles in the water

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1 minute ago, ditchcrawler said:

And so much slack it dangles in the water

At least then there's less force to pull the spike out than with a tight right-angled line, which has a huge force multiplier (basic trigonometry)...

 

I'm having spring line anchor points fitted 😉

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Ratchet strap onto the foredeck drains is quite a good way to do it. Tie up normally them have a pin several feet back from the foredeck and pull boat back against that pin with the strap. Usefully ratchet straps have little metal hooks on them. 

 

Proper 2 inch ones not the mickey mouse type. 

Edited by magnetman
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1 hour ago, IanD said:

At least then there's less force to pull the spike out than with a tight right-angled line, which has a huge force multiplier (basic trigonometry)...

 

I'm having spring line anchor points fitted 😉

Its easier to stop 14 tones moving from a standstill than to stop it once its doing 1mph. Consider laying a hammer on your thumb, even a lump hammer, now lift it a foot and drop it on your thumb.

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3 minutes ago, ditchcrawler said:

Its easier to stop 14 tones moving from a standstill than to stop it once its doing 1mph. Consider laying a hammer on your thumb, even a lump hammer, now lift it a foot and drop it on your thumb.

Also true. Either way, it's a crap way of mooring, and if people do it they can't justifiably complain to boats passing on tickover (or slowly)...

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