Our forward deck storage hatch is closed by a Lewmar GEBO hatch cover with a
very dark (almost black) acrylic window. There is always a lot of
condensation on the inside of the hatch dripping down in the storage area,
which does not have a drain. (over an average month almost a gallon of water
has to be pumped out).

Since we do not need to look through the hatch I am wondering if I could
reduce the condensation by either a) paint the hatch window with a glossy
white paint to reflect the incoming sun rays or b) glue a layer of aluminum
foil on the inside of the acrylic.

Any comments or advice will be most welcome.

Thanks
Claus

Why not leave it open or dry out the boat or both? The condensation
cycle is not a hard principle to come to terms with, Santa.

"cvj" wrote in
:

Since we do not need to look through the hatch I am wondering if I
could reduce the condensation by either a) paint the hatch window with
a glossy white paint to reflect the incoming sun rays or b) glue a
layer of aluminum foil on the inside of the acrylic.



The problem is that when the sun sets, the hatch gets colder than the air
in the boat, causing the same condensation problem you get sitting a
glass of a fine single malt Scotch and ice on a table. The air in a boat
is like a swamp, especially at night being all open like they are on the
surface of the water. So, instead of trying to regulate the sun, that
will do nothing constructive. Now, what we need to do is to keep the
warmer cabin air AWAY from the cold hatch so the condensation cycle and
the convection airflow feeding it (cold air from the hatch dropping,
replaced by warmer air sucked in across the overhead rising) more warm,
moist air.

A nice styrofoam block cut to fit tight into the hatch opening will
insulate the cold of the hatch from the warm of the boat. Costs almost
nothing and comes out easily so you can use the hatch when you want to
open it. If the boat has air conditioning, it also saves a few thousand
Btu blocking the hot sun in the daytime from heating up the air and
whatever the sunshine was cooking like the expensive woods if the hatch
is transparent. Go see the hobby department of any WalMart or one of
those hobby shops the women love. They have blocks in several
thicknesses cheap!

Don't feel bad, the swamp inside our Raymarine 2KW radome eats itself
from this condensation-at-night problem every year. The pot metal parts
corrode and white powder shorts out the PC boards exposed by holes in the
pot metal chassis. (I just put this in for my shadow Raymarine dealer
who loves for me to mention it on rec.boats.electronics.)...(c;

Don't forget to keep your fuel tank stored full. It rains in there, too!

Larry wrote:
"cvj" wrote in
:

Since we do not need to look through the hatch I am wondering if I
could reduce the condensation by either a) paint the hatch window
with a glossy white paint to reflect the incoming sun rays or b)
glue a layer of aluminum foil on the inside of the acrylic.



The problem is that when the sun sets, the hatch gets colder than the
air in the boat, causing the same condensation problem you get
sitting a glass of a fine single malt Scotch and ice on a table. The
air in a boat is like a swamp, especially at night being all open
like they are on the surface of the water. So, instead of trying to
regulate the sun, that will do nothing constructive. Now, what we
need to do is to keep the warmer cabin air AWAY from the cold hatch
so the condensation cycle and the convection airflow feeding it (cold
air from the hatch dropping, replaced by warmer air sucked in across
the overhead rising) more warm, moist air.

A nice styrofoam block cut to fit tight into the hatch opening will
insulate the cold of the hatch from the warm of the boat. Costs
almost nothing and comes out easily so you can use the hatch when you
want to open it. If the boat has air conditioning, it also saves a
few thousand Btu blocking the hot sun in the daytime from heating up
the air and whatever the sunshine was cooking like the expensive
woods if the hatch is transparent. Go see the hobby department of
any WalMart or one of those hobby shops the women love. They have
blocks in several thicknesses cheap!

Don't feel bad, the swamp inside our Raymarine 2KW radome eats itself
from this condensation-at-night problem every year. The pot metal
parts corrode and white powder shorts out the PC boards exposed by
holes in the pot metal chassis. (I just put this in for my shadow
Raymarine dealer who loves for me to mention it on
rec.boats.electronics.)...(c;

Don't forget to keep your fuel tank stored full. It rains in there,
too!

I find that a few dops of condensation in my fine single-malt Scotch tastes
a lot better than the stuff out of the water tanks, it must be the rubber or
plastic they are made from. Another way to ruin good Scotch is to use those
bloody awful water-purifying tablets in the tanks. Far better to risk death
by poisoning! Scotch is a great disinfectant anyway, it doesn't kill the
bugs, just makes them drunk beyond the point at which they can harm you.

Of course, being domiciled in Scotland for the past fifty years, I should
not be divulging that I add anything to the malt as I understand this is a
hanging offence over here. Even ice is regarded as a pollutant, and results
in a long jail sentence.

Perhaps some sort of funnel to catch the early morning dew from the hatch,
and brew the tea with it, would be a better idea than avoiding it.

PS- It's so goddam cold over here at the moment that condensation is no
problem at all. Our hatches have condensation only on the outside!

Dennis.

My canvas shop made some quilted insulating covers that installed on
the outside of the hatches. Stopped the condensation completely and
could be easily removed if needed.

Keith wrote:
My canvas shop made some quilted insulating covers that installed on
the outside of the hatches. Stopped the condensation completely and
could be easily removed if needed.

Brilliant idea!