Getting hotwater on board

[Becky]

I have hot air heating, which was fitted by the previous owner, blocking the entrance to the cockpit locker and filling one of the lockers beneath the port saloon berth with the pipe work. Very effective, but heavy on the stowage space, and I want hot water on board. My engine is raw-water cooled, and still very good after twenty years. A friend has changed his to fresh-water cooling to get domestic hot water and had a lot of over-heating problems. So I propose fitting a diesel heater for the water, with a circuit to matrix radiators to heat the boat ( with little elecric fans to blow the air), and this will enable me to have a calorifier which will suply the hot water for a shower etc. Moody's do the Webasto system, (my boat is Moody) and I am buying it from them and hopefully fitting it myself. Has anyone got experience of this type of heating and are there any pitfalls or problems I should be aware of?

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[Gunfleet]

I looked into this. The trouble is not the spondulicks (a swift course of bridgework would pay for it!) but the power.Your boat is about the same size as mine and I expect, like me, you don't have an infinite budget for electricity or space for batteries. If you compare the smallest of each webasto, the air version going part load is 9W. The water version is 27. Now I know the water version is putting out more heat, but that doesn't help on a little sailing boat when you want a little bit of warmth. You still have to find the 27W to power the wretched thing. I'd be interested in what you decide in the end. Keep us posted.

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[Becky]

Thank you to JohnM's response. It is the electricity that is the bother with the Mikuni hot air system; it uses 10 amps or so to light up, heats the saloon in five minutes, cuts out, and then starts up again a few minutes later, presumably using another 10 amps. Advice from Webasto in the form of Keto who supply the kit, is that I will use less power this way- my brochure quotes 18/23 watts low running, and I 'can use it all the time' according to them. I have concerns about battery survival, as I have loads of power-hungry equipment; fridge, autohelm, radar, chart-plotter and so on. The batteries are two 110 amp for domestic and engine starting. I fitted a battery management thingy which keeps the batteries fully charged when I am plugged into the pontoon supply, and recently added a Sterling smart regulator, which has resulted in the alternator packing up, as far as I can tell. Trouble is, being a now-single lady sailor, everyone seems compelled to give me advice, much of which disagrees with what I have been already told. And the books/mags are not much help on this subject. But I will keep posting on my progress if it is of interest.

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[roger]

Virtues of an electric kettle.

My boat is in Sweden so I can afford to use marinas hence the comment. A small electric kettle provides hot water in harbour, saves an enormous amount of gas and costs very little.
A raw water cooled engine operates at a lower temp than fresh water cooled to get corrosion levels down to an acceptable level so it makes a calorifier less effective - though some people reckon its adequate.

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[PeterGibbs]

I know that Moodys are not so easy to accommodate hot air heating - hence the space lost syndrome you describe. But since it is installed, there is a powerful argument for leaving it and using it in situ. Installing thin bore pipes and rads, with or without blowers, is costly and a further drain on battery power. It also takes a lot longer to warm the boat

For your hot water may I suggest another approach: may we assume you spend most overnights on a pontoon? If so, an electric (240v shore-powered) immersion heater will do a good job; perhaps you already have powered water delivery? I find I get a full tank in about 20 mins. Pretty easy to fit, assuming you already have good shorepower connections? When you amortise the cost of taking a power line, which also charges your batteries etc - it is worth it.

Retro fitting a hot water takeoff from the engine works in some cases - in others it can abstract too much heat to run the engine at the right temperature - thus leading to other problems. Check with the supplier.

Final point - you talk of DIY installation. There are quite a lot of snags with this kind of installation, diesel pipe runs, drilling holes (no mistakes please!) etc. When I got down to it, I decided it was worth paying a professional - now totally convinced this was correct. And I love to do as much about the boat as I possibly can!

PWG

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[chippie]

It sounds like your heater system is pretty good so I wouldnt advocate changing it.
Here in NZ lots of boats use gas califonts that work well and are relatively inexpensive .[NZ $ 269] they seem to be trouble free and there arent boats blowing up all over the place. Worth considering IMHO.

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[Talbot]

The new eberspacher heaters use a lot less electricity to maintain the temp, than the web.

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[Chris_Robb]

Only 25 watts???? my ancient Webasto takes at least 40 amps on start up! so much so it won't start unless the engine is running!

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