Bargebuilder

Our 30' narrow beam GRP cruiser has a 25hp Vetus diesel which consumes 1/2 litre per hour at 1400 rpm at which we are traveling at our usual 4mph. If there were no locks or moored boats to slow down for, we would be doing approximately 8 miles per litre or 36 miles per gallon. We draw very little water and anyway our hull has a shallow 'V' profile so she doesn't notice shallow canals unless they are incredibly shallow, hence, water depth tends to make no difference to our fuel consumption or speed. Yoghurt pots are brilliant!

...and presumably, since a freezer has considerably more insulation, it will have less useable volume inside. Perhaps a mains fridge could have more external insulation added if there is space for such, making sure that any condenser is not covered.

Try this: https://www.12voltplanet.co.uk/voltage-drop-calculator.html?srsltid=AfmBOooSKBVwqThgMtczx4pDhVFLrIfEBsXCUIOUf5awZW0XKed15rUn

Just spotted this YouTube clip to remind the OP that Dutch Barges can be a bit 'tippy'

I installed a Morso Squirrel stove on our barge using the single skin then insulated flue design that I mentioned above. Its flue came from the stove's top, had two 45⁰ elbows in it, so it started vertical and ended vertical as it passed through the roof, with a 45⁰ angled section part way up. The entire height was 2.4m, it had no damper in it and it worked perfectly and continues to do so some 17 years since installation, despite the fact that the minimum flue height is meant to be 3m! Even with just a Coolie hat on the top it drew perfectly well in all conditions.

The best combination of heat utilisation and safety is to have ordinary single skin flue from the stove too to 6" or so beneath the ceiling, then a single skin to twin skin adaptor and continue through the grp with insulated flue, through a flexible flashing and rising to the desired height. Having single skin inside gives out more heat and having insulated above both protects the grp and keeps the flue gasses warm to maintain a good draw; important when the flue height is short. Alternatively, if you want to avoid lugging to the boat and storing wood and coal, you could consider a drip feed diesel heater. Like a wood burner, you can see the homely flame through the glass window and they too don't need electricity to operate. (Apart from a fan on start-up if you bother to use it).

You'll get a better draw from a top flue, particularly if the total flue height is at the minimum as recommended by the stove manufacturer. This stove is a small 'copy' of the Morso Squirrel stove and very good if space is limited and 4kW is sufficient for you. https://salamanderstoves.com/product/the-hobbit-stove/ Have a chat with them perhaps. There are lots of flexible pitched roof flue flashings that can be adapted for a boat. You'll need to use insulated twin wall pipe where you penetrate the ceiling of course. Internally, you can buy a sheet of copper for example and cut in it an oval shape to act as an internal trim around the pipe.

Quite so, but it's possible to live aboard with a much cheaper inverter, so the savings need to bridge the gap. My 'big' inverter was a bit more than £100, a quasi, and I'm guessing that a Victron, with the bells and whistles necessary would be many times that. We had a tiny Victron for sensitive bits of equipment, that wasted hardly any 12v and left that powered up most of the time.

We used propane as the only means of cooking and heating water and we only used about 3 x 13kg bottles of propane each year whilst we lived aboard; it goes further than one might think. Even the kit needed to divert excess solar generated power to an immersion heater might be hard to justify compared to just using a gas or diesel boiler all year round.

Ovens that run on propane, or can be converted, were certainly available when I fitted out our barge. We had a gas hob and oven mainly to keep 12v consumption to a minimum, plus the wife prefers cooking on gas. We only used chargers during daylight hours to soak up PV output and we had a very small output victron inverter that we used during the winter, that had a tiny quiescent current draw, only powering up the big inverter when it was needed for say the vacuum cleaner.

It's 15 years since I bought from Chemco, so you'd have to phone them for a price. I don't think they have a minimum order, because they sent me two 500g tins, one of the primer and one of the top coat. The carriage was a bit pricey, but worth it for such an excellent product. I understand that it was designed for use on ships water tanks, ballast water tanks, power station cooling water intakes and domestic water authority water storage facilities.

Use a surface tolerant primer and a really good top coat and you'll probably never need to paint the tank you've got ever again. I prepared my built-in tanks with a wire cup brush and then used this two pack coating. https://www.chemcoint.com/industries/marine/vessel-area/potable-water-tank-coatings/#solvent-free-wet-and-rust-tolerant-system The finish is a very light grey, shiny, and hard like enamel (but not that hard of course) and has lasted already for 15 years with no degradation. I'm confident it will be good for at least another 15 years. It is fully certified as safe for potable water. It is easy to apply thickly using a small roller or a big brush. It's got to be easier and cheaper than a new tank.

Just look at this: They have barge sailing races in Holland, as indeed they do with Thames barges in the UK. Coastal passages are common, now and when they were goods carriers.

Have you estimated how big the battery bank would need to be? We found November to be the most gloomy, misty month and often solar contributed almost nothing for almost two weeks at that time.

Very roughly, if your 3 panels produced about 3 kWh on a summer's day, then during the bleak winter months one might only expect 10% of that, so if 1 kWh is needed as a minimum, then 10 panels would be needed in December. Of course, one could run the engine or a generator, or as we did, turn off the freezer and anything else we could do without.