Winterisation - cabin heating by spare solar power?

[Scholar Gypsy]

So for the last 40 odd years we have

• drained the water system, including the calorifier
• left all the windows open
• left the curtains hanging loose

 

... and have had no problems with condensation or mould (though the boat can get a bit cold!). 

 

I am toying with the idea of connecting the dump/load terminals on my solar system to a 12V heater, eg a greenhouse heater. Such things do seem to exist, and I think if they are a pure resistive load they will cope with whatever power the controller can deliver to them.  (which in the depths of winter is unlikely to be more than 50W,  I have 200W of solar panels lying flat on the roof).

 

Has anyone tried this? Did it make a blind bit of difference, or work any better than a night light underneath a flowerpot?

[DaveR]

After so many years of successful layup why change? Why do you think it is needed?

 

I too do as you have done for so many years, we are away from the boat October to March (other than an odd visit to make sure all is OK ) and like yourselves had no problems. It doesn't take too long to empty the boat of water & left over groceries, which if still in date go to the food bank, and It is also good to make sure the boat doesn't slowly fill up with accumulated. "stuff".

 

It just takes about 2 days to warm the boat up in the Spring.

[Scholar Gypsy]

11 minutes ago, DaveR said:

After so many years of successful layup why change? Why do you think it is needed?

 

I too do as you have done for so many years, we are away from the boat October to March (other than an odd visit to make sure all is OK ) and like yourselves had no problems. It doesn't take too long to empty the boat of water & left over groceries, which if still in date go to the food bank, and It is also good to make sure the boat doesn't slowly fill up with accumulated. "stuff".

 

It just takes about 2 days to warm the boat up in the Spring.

It's a fair question - though I do go cruising all year round. I have a complex system of valves and pumps so draining the water takes only five minutes, and ditto filling it up at the start of a cruise.  I guess I like gadgets ....

[frangar]

I have 240w of solar flat on the roof…I’m lucky to get a max of 70w output and about 25-30ah on an average winters day…if it’s bright sun it’s more obviously. I wouldn’t think you will get enough to make a heater produce any meaningful heat. I’d stick with what you have been doing. 

[blackrose]

Even if you could get some heat out of the greenhouse heaters from your solar panels, it's not going to raise the temperature very much if the windows are left open.

 

My boat is on shore power at my mooring and if I'm away in for a few weeks in winter an electric oil filter rad is left on at 5C with the windows closed. I've never had any damp or condensation issues. I assume the boat's fixed ventilation provides all the air flow it needs to stay dry.

Edited November 12, 2021 by blackrose

[Bee]

Solar electric probably would not work too well. Solar water panels (matt black radiator things) would be better but need a small pump but I wonder if the most effective use of solar would be to just cover the boat in a black plastic sheet with a few holes in the right places?

[ditchcrawler]

1 hour ago, Scholar Gypsy said:

So for the last 40 odd years we have

• drained the water system, including the calorifier
• left all the windows open
• left the curtains hanging loose

 

... and have had no problems with condensation or mould (though the boat can get a bit cold!). 

 

I am toying with the idea of connecting the dump/load terminals on my solar system to a 12V heater, eg a greenhouse heater. Such things do seem to exist, and I think if they are a pure resistive load they will cope with whatever power the controller can deliver to them.  (which in the depths of winter is unlikely to be more than 50W,  I have 200W of solar panels lying flat on the roof).

 

Has anyone tried this? Did it make a blind bit of difference, or work any better than a night light underneath a flowerpot?

What if there is a sprinkling of snow on the panels for a week 

[Jen-in-Wellies]

55 minutes ago, ditchcrawler said:

What if there is a sprinkling of snow on the panels for a week 

And if it is snowing, it is also cold. If the temperature drops further the snow will stay there and not melt; it will go below freezing inside the boat and the solar panels will be producing nothing. It takes a while for snow to melt on a boat roof with a stove inside, with decent insulation. Again, with a stove on and multi kilowatts of heat, the panels take even longer to clear as rigids are mounted above the roof. Some greenhouse heaters are going to do next to nothing to clear the snow from the panels.

It might reduce condensation, but wouldn't remove the need to drain the water system. You'd need something to disconnect the panels if the battery draw became too great. A couple of hundred watts of heater would be a big drain on the batteries if there is next to nothing going in from the solar.

Jen

Edited November 12, 2021 by Jen-in-Wellies

[OldGoat]

When we started boating ('a generation ago') I did the usual winterization (!) process and fitted an 800W oil radioator with a thermostat and time switch. It achieved little or nothing -  I tested that by visiting the boat at a time when the radiator would be on. The boat was cold! The only casualty was a tap in the rear loo facing North that froze.

 

Later a fellow boater on the Thames fitted his cruiser (not steel) with  digital thermometers and recorded the fluctuations. In the engine bay the temperature never fell below 4 degrees C - even though the temoeratur externally was much less. The boat was in a marina where there is little flow (if any), the surface of which did freeze.

The conclusion was that heating  / not heating made no difference to frost damage.

What is worth doing - IMHO - is as mentioned above, turn off the water pumps, open all the taps, flush the loo(s) and turn off the flush supply.

The theory is that if the water expands > 4 degrees, then the denser water has somewhere to go.

It's worked for me ever since - but it's warmer here darn sarf....

[ditchcrawler]

I had a pipe joint go in the toilet on a bit I failed to drain also had the pipe from the cold water tank pop on the share boat we use to have.

[Slim]

I've always done much the same as Scholar Gypsy but with portholes I rely on mushroom vents for ventilation. I do however empty the Squirrel and leave the door open with chimney left in place. Never had an issue to date. 

I've often wondered what the temperature falls to over the winter and have just bought two temperature data loggers to leave on the boat. I'll be interested to see what the temperature drops to compared with weather forecasts for the area. 

[system 4-50]

Leave the boat on a dry day.  Before you leave the boat, run the stove hard and get the temperature inside the boat hot.  This will get any dampness in the boat into the air.  Shut down the stove and open the doors fully.  The hot "damp" air will leave the boat and be replaced with cold dry air from outside.  Close all windows & vents including your Morco flue.  When this is complete, shut the doors smartly (with yourself outside).  There is now no dampness in the boat and no way for it to get in, so no mould/condensation will occur.  This method is not tried and not tested but I'm applying for a patent at the Bizzard Patent Office.

[GUMPY]

9 hours ago, Slim said:

 

I've often wondered what the temperature falls to over the winter and have just bought two temperature data loggers to leave on the boat. I'll be interested to see what the temperature drops to compared with weather forecasts for the area. 

Even last week when it wasn't very cold my boat sent me a txt saying it was below 6deg C inside the boat at 04.17 one morning in Northamptonshire.

Have reset the trigger point to 4C and we will see when that triggers.

 

ETA it certainly doesnt seem as cold in winter as it was 30 years ago.

Edited November 12, 2021 by Loddon

[ditchcrawler]

31 minutes ago, Loddon said:

Even last week when it wasn't very cold my boat sent me a txt saying it was below 6deg C inside the boat at 04.17 one morning in Northamptonshire.

Have reset the trigger point to 4C and we will see when that triggers.

 

ETA it certainly doesnt seem as cold in winter as it was 30 years ago.

Coo I am glad I don't have one of them. Its bad enough getting up for the loo but then a couple of hours later to have the phone call  you to tell you boat is a bit chilly.

[TheBiscuits]

14 hours ago, Scholar Gypsy said:

I am toying with the idea of connecting the dump/load terminals on my solar system to a 12V heater, eg a greenhouse heater

 

In winter the only times you'll have spare solar is on the odd few very clear bright days.  Direct solar heating of your boat (sunshine on the hull/cabin) will make a lot more difference than dump load heaters in these conditions.

 

 

Edited November 12, 2021 by TheBiscuits
clarity

[Scholar Gypsy]

12 hours ago, Jen-in-Wellies said:

And if it is snowing, it is also cold. If the temperature drops further the snow will stay there and not melt; it will go below freezing inside the boat and the solar panels will be producing nothing. It takes a while for snow to melt on a boat roof with a stove inside, with decent insulation. Again, with a stove on and multi kilowatts of heat, the panels take even longer to clear as rigids are mounted above the roof. Some greenhouse heaters are going to do next to nothing to clear the snow from the panels.

It might reduce condensation, but wouldn't remove the need to drain the water system. You'd need something to disconnect the panels if the battery draw became too great. A couple of hundred watts of heater would be a big drain on the batteries if there is next to nothing going in from the solar.

Jen

On the last point, that's why the heater would be connected to the dump terminals, not direct to the batteries.  I think I will stick with plan A.

[GUMPY]

1 hour ago, ditchcrawler said:

Coo I am glad I don't have one of them. Its bad enough getting up for the loo but then a couple of hours later to have the phone call  you to tell you boat is a bit chilly.

Phone is on slient now so it doesnt happen again. I slept through it C didn't

 

[blackrose]

12 hours ago, OldGoat said:

The conclusion was that heating  / not heating made no difference to frost damage.

 

I really think that depends on how cold it gets and also what level of winterisation one does.

 

My oil filled rad is set at 5C on the 1kW setting and it certainly lifts the temperature in the boat by a few degrees. I'm only away from the boat for a few weeks at a time so I don't do the full winterisation drain down. All I do is switch off the pump, isolate the tank and open a couple of taps. So in my case the heater does make a difference.

Edited November 12, 2021 by blackrose

[Machpoint005]

I haven't done the calculations but it seems to me that if you are seeking to use energy from the sun to heat the boat, it's unnecessarily wasteful to convert it into electricity and then back into thermal energy.

[MtB]

2 hours ago, Loddon said:

ETA it certainly doesnt seem as cold in winter as it was 30 years ago.

 

I notice this too.

 

Back in the day I recall periods of weeks on end in most winters when the temperature stayed below zero, even down here in the south. Not noticed this happen for at least a decade now. 

[Machpoint005]

Perhaps we should tell those folk who are currently meeting in Glasgow?

 

[MtB]

Just now, Machpoint005 said:

Perhaps we should tell those folk who are currently meeting in Glasgow?

 

 

I think they've noticed, which is why they are having a meet-up, Shirley! 

[Briss]

Are these type of condensation traps effective?

[Tony Brooks]

37 minutes ago, Briss said:

Are these type of condensation traps effective?

 

In a cupboard or small confined space, maybe. for a whole boat I would say no chance,  especially if you leave windows open to let damp air back in.

[GUMPY]

9 hours ago, MtB said:

 

I notice this too.

 

Back in the day I recall periods of weeks on end in most winters when the temperature stayed below zero, even down here in the south. Not noticed this happen for at least a decade now. 

I spent the whole of January one year, 1997?, frozen in down the Aylesbury arm the temperature rarely got above freezing during the day and the ice on the canal was eight inches thick. Even the pound with the sewage outfall at Bourne End froze that year.