I am guilty of sticking my head in the sand about freezing the tank. I
didn't think it was going to be that cold. A few days later the tank
thawed out (I had removed the drain cap to allow the melt to drain), I
knew it was thawed completely when, by good luck, i was in the van and
suddenly an unexpected noise started - it was the pump. I have an
Eurovan faucet that does not have a spring loaded valve, so I guess I
had the water turned on by accident. I think I will go out now and
check it.

The calculation on heat loss from water tank is beyond me. Heat flow
etc, argh.

I have the tank insulated with closed cell foam where it rests against
angled engine compartment wall and the floor. The other sides are left
bare (pic here: http://shufti.files.wordpress.com/2010/08/
img_2020.jpg). I really should have done all walls. I think I will
when I take out the cabinets (again!) this spring. And why not
insulate the water lines.

Having a tank water warmer for winter camping would be a good thing,
just to keep above freezing, not to culture bugs :)

alistair

On 13-Mar-11, at 2:00 PM, David Beierl wrote:

> At 01:47 PM 3/13/2011, Alistair Bell wrote:
>> was windy, if that makes an difference :)
>
> Big difference to the cooling rate, none of course to the ultimate
> temperature.
>
> The little centrifugal pump hanging in the bottom of the tank in the
> later ones can definitely burst if it freezes.  Dunno about the
> external one.  The P-trap could be a problem too, as well as the
> lines themselves.
>
> Personally I'd put water-system antifreeze in the lines and not have
> to worry about them.  Carry water in gallon jugs inside boxes with
> newspaper, stick one or more hand warmers in the box overnight.
>
> Alistair, shall we expect a graph showing number of handwarmers vs
> outside temp vs inches of newspaper, with correction factors for air
> supply to the handwarmers?
>
> On Scamp we always carried a Sunshower(TM) on deck - clear front,
> black back; on a sunny day you could get a hot shower and
> surprisingly often it was at least warmish.  Was set up for maximum
> economy of showering though, not for getting a glass of water from.
> Should have worked, though - and you could sleep with it if you put
> a pillow case over it.
>
> Yrs,
> d