Coming back to the marina Saturday evening about 30 minutes before sunset the outside temp was about 80 degrees and it was very humid. We had several thunderstorms during the day. I had the cockpit and cabin air on and set around 70 degrees. The windshield vents were open and the back curtain was off and open air. All of the sudden the windshield fogged over inside and out and visibility was almost zero through the glass. We tried the washer on the outside, wiping down both the inside and out and nothing seemed to clear the fog and condensation.. I put a fan in the windshield to help and crawled back to our slip very slowly looking through the vents. I noticed about 2 hours later the window was finally clear. Has anyone else had this issue and is there a quick solution? Should i turn off the air before moving in a humid situation? I was almost dead in the water and if i had not been so close i probably would have had to sit out the evening on the hook.
48da windshield fogging/condensation
- Thread starter bwehby
- Start date
missnmountains
Active Member
Every early morning departure we deal with this issue as we idle out our canal. We never run the A/C that early. There is just too much moisture inside and out which fogs up the inside and outside of the windshield.
Once up to cruise speed, with the vents open, it clears up.
Unfortunately, it is a case of the 1st mate keeping a mop and shammy running.
Once up to cruise speed, with the vents open, it clears up.
Unfortunately, it is a case of the 1st mate keeping a mop and shammy running.
sbw1
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- Oct 10, 2006
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We run with our drop curtain installed to keep the humid air on the outside. Seems to work for us.
Perhaps if you understood the science behind this strange phenomenon you would be able to better control it.
Your glass is cold. The air is dry. The air is clear. Nothing happens.
Your cold glass enters air holding moisture, the air still looks clear, the mosture condenses on the glass.
Try putting a cold glass in the freezer for an hour on a hot muggy day. Take it outside and see what happens.
The air over a body of water can change rapidly in both temperature and water density. You can't control that.
What you can control is the temperature of your glass, at least in the 48DA. If you are running the AC at 70 deg with the vents blowing on the windshield, of course it is going to fog up if you go from relative low humidity to high humidity.
If the glass is at the same temperature or warmer than the air, water will not easily condense on it. Running the reverse cycle heat with the windshield vents open while idling out the canal should prevent the condensation.
Your glass is cold. The air is dry. The air is clear. Nothing happens.
Your cold glass enters air holding moisture, the air still looks clear, the mosture condenses on the glass.
Try putting a cold glass in the freezer for an hour on a hot muggy day. Take it outside and see what happens.
The air over a body of water can change rapidly in both temperature and water density. You can't control that.
What you can control is the temperature of your glass, at least in the 48DA. If you are running the AC at 70 deg with the vents blowing on the windshield, of course it is going to fog up if you go from relative low humidity to high humidity.
If the glass is at the same temperature or warmer than the air, water will not easily condense on it. Running the reverse cycle heat with the windshield vents open while idling out the canal should prevent the condensation.
Robski97
Well-Known Member
AS mike said u should turn on the heat. Thats what i do in the am to defog and go.
Rob
Rob
missnmountains
Active Member
Julia & Rob,
Unfortunately, the vent up front does not blow on the windshield. I agree this would work for him (and us), but only if you kept the curtains on and heated up the cockpit area enough to heat up the windshield.
This might work in Tennessee for Bwehby, but I doubt it would work in southwest, fl.
It would have been nice if the vent for the cockpit air vented onto the windshield.
Ken
Unfortunately, the vent up front does not blow on the windshield. I agree this would work for him (and us), but only if you kept the curtains on and heated up the cockpit area enough to heat up the windshield.
This might work in Tennessee for Bwehby, but I doubt it would work in southwest, fl.
It would have been nice if the vent for the cockpit air vented onto the windshield.
Ken
tobnpr
New Member
Unfortunately, I don't have cockpit air...but I don't see how it's different then a car, assuming it's enclosure is relatively "tight".
Once the air has been running long enough to dehumidify the interior, any fogging on the interior side should disappear. The problem is that the windshield vents were open and the back cover was off. Seal it up tight, and let the A/C dehumidify the cockpit. You might still get condensation on the outside because of the cooler glass, but your wipers will take care of that.
Once the air has been running long enough to dehumidify the interior, any fogging on the interior side should disappear. The problem is that the windshield vents were open and the back cover was off. Seal it up tight, and let the A/C dehumidify the cockpit. You might still get condensation on the outside because of the cooler glass, but your wipers will take care of that.
Robski97
Well-Known Member
Ken,
Im up in NY . Ur set up is much better then mine. All my vents face the helm seats. But anyway Ive used the heat in the morning to defog the winshield from morning dew. Its not instant for sure but stops it from getting worse. Was just a suggestion .
Rob
Im up in NY . Ur set up is much better then mine. All my vents face the helm seats. But anyway Ive used the heat in the morning to defog the winshield from morning dew. Its not instant for sure but stops it from getting worse. Was just a suggestion .
Rob
All my vents face the helm seats as well. (Even the one under the windshield.) i will chalk this up to design flaw. it reminded me of my first car a 1971 ford maverick that fogged over all the time, but at least in it i could hang my head out the window to see. I will try the heat next time and be mindful on humid days to cut off or bring upthe cockpit and cabin air to the outside temp before getting under way. I guess what was so unnerving about the situation was that it happened instantly while coming down in speed so dropping curtains and turning the heat up and so forth isn't something that can be done quickly.
Robski97
Well-Known Member
I thought the Under the window vent was well for the window... Silly me ...
Just another in the long lists of WTF where they thinking ?
Anyway So love the 48!! Wish u the best
Rob
Just another in the long lists of WTF where they thinking ?
Anyway So love the 48!! Wish u the best
Rob
LifeisGood
Member
Has anyone ever used a 12v defogger before? I found one on West Marine's site for $34, but I am not sure how sell it would work.
Rich122
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- Aug 7, 2007
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Using the heat works,
Although the "windshield" vents do face forward they are very close the the bottom of the "raked" windsheild and as the heat rises it clears the fog. I leave the A/C on many nights and come out to a comofrtable cockpit for morning coffee, and yes the windsheild is fogged over. If I know i'm leaving early for a trip i leave the A/C off until well under way.
Rich
Although the "windshield" vents do face forward they are very close the the bottom of the "raked" windsheild and as the heat rises it clears the fog. I leave the A/C on many nights and come out to a comofrtable cockpit for morning coffee, and yes the windsheild is fogged over. If I know i'm leaving early for a trip i leave the A/C off until well under way.
Rich
