Bargebuilder

Most definitely, you would only choose a 4 blade if 3 didn't offer the 'grip' on the water that was needed.

To increase the disc area ratio: a common trick where a bigger diameter is not possible because of clearances or maybe desirable if picking up rubbish from the bottom is a concern.

Ah, that's why I wasn't aware of pro oil propaganda, I don't take a newspaper and I've never been on Facebook. They won't be aiming their investment at me anyway, as I won't be swapping my diesel car or boat for electric any time soon.

I'm not questioning you, but you've mentioned the billions that oil companies are spending on pro oil propaganda many times, but what are they spending it on? Perhaps my life is a sheltered one, but I can't think of an occasion when I've been aware of being influenced to keep using or to use more oil.

I'm guessing that most of us are not thinking as far forward as 2050; if only! As for the availability of diesel, nobody knows, but if nobody is using oil for vehicles or heating then it could be that the remaining reserves will last pretty well. Supply and demand is a huge driver of fuel costs and who knows what will happen when none of us are using much of it any more.

That's what you would expect, but it doesn't mean that going big is better for the engine or its fuel consumption or even for the noise level in the cockpit if proper noise attenuating methods and materials are used.

Silence is indeed golden, in more ways than one. It must be lovely to hear nothing but the gurgling of the prop in the water from an electric powered boat, but in comparison to installing a 25Hp diesel, a diesel electric setup with super silent generator, lithium batteries, running gear, control gear, solar panels plus their charge controllers, doesn't come cheap unless you are confident to go second hand. In fact, a new super silent generator alone would be of similar cost to a 25Hp inboard diesel. The diesel inboard wouldn't be as silent as the electric, but properly silenced, it could be made quieter than most narrowboats today with 43Hp diesels run at very low revs to their detriment. I'm not sure how relevant fuel economy is between a small diesel inboard and a diesel electric given the huge installation cost disparity. If a 25Hp inboard diesel burns 3 litres of diesel in a 6 hour cruising day, just how much money can you save by going diesel electric and would the payback time have been reached before the diesel electric equipment needs replacing? We know the inboard diesel should be good for 30, 40 or even 50 years, but an electric motor in the bowels of a boat?

You are spot on of course, and yes, why wouldn't engine manufacturers push the bigger engines in their range. When buying a new boat, I understand why people think bigger must be better, but is it? A modern 25Hp diesel, I know from personal experience only consumes an average of 1/2 litre per hour when run at 1600rpm with the prop only needing 4 or 5 Hp in order to achieve canal cruising speeds; a fuel consumption figure that includes time at tickover past moored boats and in locks. Surely, before we consider investing huge sums of money into going fully electric, we should consider a smaller diesel, running it more efficiently and burning less fuel and using sound attenuation techniques to achieve the silent cruising that we all crave.

I come from a lumpy water background where it seems to be much more common to look after ones diesel engine by routinely running at around 2/3 throttle, both because that's where the engine is more efficient and also because it is much better for it. Endless hours running a big engine outputting just a few horses to achieve 3mph or just to charge batteries will long term risk cylinder glazing and poor compression. I don't understand why many narrowboaters would rather abuse an engine of twice the necessary Hp by running it at a tiny fraction of its capability just for a 'quiet life', when lumpy water boaters often install a correctly sized engine, run it at an output that's good for it and use sound attenuating multi density, 'lead' lined foams for blissfully silent cruising. I know it's possible to 'silence' a narrowboat engine because I often remark on very quiet boats and am often told about sound insulation and hospital silencers etc. If even for emergency stopping and pushing against a current only a 25Hp diesel is needed, why not save a bundle on the installation, buy a smaller lump, fit modern sound insulation, run it at an output that's good for it, match a nice bid grippy propeller via an appropriate gearbox and save money on fuel as well.

Thanks for that, very interesting. So given that a 9Hp engine of old was thought to be sufficient in a narrowboat, what Hp rating would be sufficient in a modern engine given the correct gearbox and big grippy propeller to effect an emergency stop if needed? It seems that as the years have gone by, what is deemed as an appropriate number of Hp has risen and risen; perhaps too far?

So, if you have a modern high revving diesel with relatively low torque and swap it's gearbox for one that has a lower gear ratio, at the shaft the torque increases and the revs. reduce and a big grippy propeller like the ones used on low Hp vintage engines can be swung; is that correct?

Ah, but weren't the Hp developed by 'vintage' engines magic Hp, being much more useful than modern Hp, even where a modern engine is gearboxed so it can swing a prop of a similar diameter, pitch and DAR to that of the 'vintage' engine?

That looks really good. I wonder if it could be adapted for use with a urine separator, as you might have hit upon a good looking, portable and cheap idea for anyone thinking of trying 'composting'

The users of separating loos may find the results of that survey really encouraging, if only 2% of boaters use separating toilets, but between 25% and 45% of boaters either support or aren't bothered by the practice of bagging and binning. That might imply that there are far more than 2% of boaters who might in the future give serious thought to using separating toilets themselves. Just imagine the increase in popularity and acceptance of the use of separating toilets if a properly organised 'humanure' collection service were to be laid on.

Short of the C&RT saying 'please, please put your toilet waste in our bins' they couldn't have done much more to encourage such misuse. With all the other advantages of separating loos over pump-outs and Elsans, the C&RT solved for many the only barrier to 'composting', what to do with the product. Of course the C&RT are in part responsible for the jump in popularity of separating toilets.

By offering the free and hassle free removal of uncomposted toilet waste, of course the C&RT were encouraging the proliferation of the use of separating toilets. I'm sure that wasn't their intention, but it was certainly the effect. Now it's time to look at composting and decide if it has advantages over the alternatives and if so, devise a way of making it work safely for all.

I don't think even committed composters/separators would disagree with the points you make. As most people are unable or unwilling to complete the composting process on board, the only acceptable solution is for a collection system for all. The annual increase in licence fee would have to be about £7 higher than it otherwise would, but would we notice? The question is, is the 'dry' collection of toilet waste a better system than either pump-out or cassette and so worth pursuing? There have been listed a host of reasons why separating might be better than pump-out or cassette, but very little for the reverse position, apart from a chorus of 'why should we pay'! IF it is such, should we persist with an inferior system just because the transition poses problems that need solving?

It is also possible, but I accept extremely unlikely, that boat owners with pump-outs and cassette toilets will discover how much more pleasant separating toilets are to live with than either, and want to enjoy the many benefits to them and of course to the environment. Yes, if the cost of collection were spread across all licence payers it would amount to an increase of about £7 each, but that represents perhaps 1/2 or 1/3 of the cost of a single pump-out. Cassette toilet users, who's toilet choice is currently subsidised, would of course be about £7 a year worse off, but even they, having made the change to composting, I'm sure would never want to change back.

Indeed you do. Having lived on a barge with a pump-out and then changed over to a composter and been delighted that I did, I'm sure that there will be readers who are looking for information and an insight into the experience of others before they choose what to install in whatever boat they own.

I think that you are right, but there won't be a demand if separating toilets are banned: I hear a huge chorus, GOOD! But what if separating toilets have advantages over pump-outs and cassettes, and maybe are overall better, both for the user and for the environment, with the only unsolved issue being the arrangement to collect and process the waste? If the waste is commercially composted for use as a soil conditioner and fertilizer, then the use of manufactured artificial fertilizer could be reduced. Such fertilizers being neither environmentally friendly to manufacture or to spread onto our fields with the resulting run-off into water courses. If the waste was sent to a digester, the gas produced could generate electricity and waste heat could heat glasshouses for the production of crops. Not just the humanure from boats of course, but in 2010, composting toilets were given official approval by 'Building Control' for use in domestic dwellings as an alternative to flushing toilets. If you'll excuse the pun, there is a movement towards composting loos, and for good reason. I understand of course that nobody wants to pay, and I see no reason at all why they should, but: Separating loos: 1. cost a tiny fraction to Instal; perhaps 1/10 or less of the cost of a macerator, tank and all the associated cabling and plumbing. And: Lower input of raw material and energy in the manufacture of a composter compared to the ceramics, pumps, plumbing and storage tanks of pump-outs. 2. Cannot block; ever. 3. Cannot smell within the boat and usually hardly noticeably outside. 4. Require you to store two or three small buckets (10Kg each) of maturing compost, instead of hundreds of litres of the most foul smelling slurry. 5. Avoid the often unpleasant nature of macerator toilet repairs and maintenance tasks. 6. Avoid the regular carting of heavy toilet cassettes and those splashes in the eye! 7. Vastly reduce the amount of water you need on board and so the frequency of fill-ups compared to a boat with a flushing macerator loo. 8. Avoid the need to contaminate highly processed and valuable, pure drinking water and the subsequent processing of liquid sewage, some of the processes being consumers of energy and chemicals. 9. Avoid the need to use 'blue' chemicals that may be toxic to the environment. 10. Have almost zero maintenance costs: no macerator pump or control box failures, no flexible hose replacement, no aggressive 'black' water eating away at steel or even stainless steel tanks from the inside. 11. For static live-aboards, means no more trips to the pump-out in mid-winter when the canal might be frozen. 12. The compost produced is an excellent soil conditioner and useful fertiliser, reducing the need for energy hungry, industrially produced inorganic chemical fertilizers.

We don't know how may people compost, we don't know who they are and the equipment they use is lightweight, need have little or no fixed pipework and is pretty much portable: good luck with enforcing a charge specific to just them.