Friday, 31 July 2009

Hot Towels Sir ?

There are two types of canal boating; soft boating and camping on water.

Personally speaking, my days of sleeping on camp beds and wearing fleeces indoors are far behind me.

Sometimes, I see people cruise by in sailaway narrowboats. The inside of the boat is just one corridor, with a plywood floor, no partition bulkheads and a Black and Decker Workmate for a table.

I appreciate that people need time to fit out their sailaways and often the temptation for a cruise on a sunny day is too much. However, I'm talking about that small band of hardened souls who are continuously cruising whilst barn-camping inside. You know who you are !!

Power to their elbow - I'm too old, soft and southern for such boating.

I like my creature comforts and one of my top priorities, especially in the damp of, well, every month except possibly August and September, is the hot towel.

I absolutely abhor reaching for a damp towel when I get out of the shower.

Willawaw has a large calorifier (the boaty term for a water immersion tank). This can be heated by the engine coolant, the Eberspacher diesel heater or an electric immersion heater when we are on shore mains.

Our interior boat heating is by radiator and these are heated by the Eberspacher. We also have an independent solid fuel stove, which burns coal or logs.

We have just finished our refit in drydock and the boat is looking pretty good. She was getting a bit tired and she now has a nice new paint job, new fenders, all her woodwork varnished or painted and so on.

The canals get a bit manic for us during the school holidays, so we tend to do repairs in the summer and start cruising in earnest just as the kids are going back to school. September and October are some of the best boating months, in our humble opinion.

Anyhow, I digress yet again.

Now, sorry to talk about those colder, damp, autumnal evenings in the middle of your summer holidays, but you have to think ahead on boats and it's not really that far away.

When we cruise in the darker, colder months, it can get quite chilly inside the boat during the day and we have to run our Eberspacher or solid fuel stove at the same time as the main diesel engine.

The former provides the heat and the latter is driving the boat forward. This is a bit wasteful, as it burns two lots of fuel, but it is necessary to stop the boat cooling down inside.   

However, this week I was given an idea by another boater.

In essence, what he was advocating, was a modification to the pump within the Eberspacher heater.

When we are cruising, the water in our calorifier gets heated by the engine and the heat will naturally transfer from the engine coil in the calorifier through the calorifier itself into the second dedicated coil for the switched off diesel heater.

As the radiators are connected to this second coil, if we could pump the water round, with the heater still OFF, we would effectively get hot radiators from the conducted engine heat, even though there is no direct connection between the two circuits.

This means there would be no need to use extra fuel for heating when cruising in the cold weather.

Whilst I applaud the notion, I'm not keen on modifying the internal pump circuitry in my Eber, BUT it would be easy to fit a second 12V pump into the pipe circuit !!

With this is mind, I plan to fit a new pump in parallel to the Eberspacher, together with some one-way check valves in the HEP plastic piping, so that the pumping pressure of the Eber when thats running can't short circuit through the stationary new pump and miss the radiators out completely.

I have ordered the HEP parts and a Jabsco 59520-0000 ecocirc pump. The pump is designed for hot water use and has a brushless motor with a magnetic drive, so it should run forever and as it has no seals, it shouldn't leak this side of doomsday.

I have also found a 12V supply on my alternator controller which will automatically run the pump only when the engine is running.

This is necessary because if you have the pump manually switched and you forget to turn it off when you stop cruising for the day, all the heat from the radiators will flow back in the reverse direction and keep the engine warm when it gets switched off, which is  counter-productive.

Anyway, bottom line is that it gives us warm rads whilst winter cruising, without burning extra diesel and just as importantly, it means that I can have just the towel rail on whilst summer cruising.

So, thanks to a bright idea from a fellow boater, I can now pat myself on the back for being eco-friendly and use a fluffy, hot towel to do it !!


  1. Sounds good... where there's a will there's a way. I'm guessing the cost of a new pump isn't that expensive?

  2. I have often wondered about this myself, but have never even been as close as thinking about how to do it never mind doing it. You are to be congratulated on your enterprise and resourcefulness.

  3. Hmm, its a take on a plan I have been hatching for Wand'ring Barks hower room refit this winter. My plan is to take a spur off the heat exchanger to calorifier pipe and then feed this through a radiator which is robust enough to withstand the pressure of the cooling system. WB does not have central heating beyond the solid fuel stove and an eco fan, which simplifies integration with a pre existing central heating system. My question is: what sort of radiator do I need!

  4. There are many pumps that could work. I went for an expensive one as I don't want it leaking after a year or two. No idea about the radiator. There is a discussion thread about this on the Just Canals forum. Just post the question on there and I'm sure somebody will know.

  5. I have a Johnson pump taking water from the top coil in the calorifier and pumping it through a radiator. The location of the pump is critical so that it self bleeds, it must not run dry. Also I find it a bit noisy with quite a loud wheeeesss


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