Until I read your post, I thought my NICRO solar powered vent fan in the hatch was pretty useless but now I see it as a fairly smart toy. The fan runs 24 hrs on its rechargeable NIMH "C" battery, charged by a small solar panel on top. My plexiglas hatch (Bomar, I think) has a section in the middle big enough to accommodate a 4" hole thru which the fan unit drops. To avoid drilling screw holes thru the plexi, we secured the fan with silicone caulk. Only once in the 10 years of operation did I have to reseal it.

I bought it to keep fresh air circulating and to pull out excess heat during our Chesapeake Bay broiler summer days. But that draw is fairly small and not very effective. The other use was for winter storage to keep moisture from being trapped in the cabin and creating mold/mildew.

For you (and now I see, for the rest of us), I think its value would be to reduce moisture around the hatch. Not eliminate it, but cut it way down. We still get some dew on the inside, but not enough to drip a lot. In addition to ventilating, consider turning down the heat to the lowest point of comfort.

I put in a solar Nicro vent too and it works great. The only problem I had was that my slip is pretty shady and the battery lost its ability to re-charge. The manufacturer replaced if for me and now I just run the fan as needed.

Fields

Here's a gauranteed fix: Remove the hatch, turn it upside down and fill it with spray foam. (Can't see out of it anyways.) Level the foam off, let it cure hard, then cover it with cloth glued in place with contact cement.

Jeff

That's a cheap solution. Put some insulating material in a waterproof cover and lay it over the hatch, securing it with a weight, Another one inside, secured as cleverly as you can imagine.

If insulating from the interior, the panel of sunbrella and insulation would have to be sealed or the worm moist air would still creep through any openings and since the space between the insulated panel and cause even more condensation. It would almost seem that the insulation would need to be on the exterior including around the frame ... much the same concept as insulated windows or storm windows in a home. Remember when we used the insulated curtains on the interior of our home and had the old single pane windows, the condensation between the curtains and the window was severe and froze on the inside of the glass when cold enough.

This condition only occurs when staying on the boat because of moisture created by the body and any use of the water systems. I never notice condensation when I check on the boat in real cold weather and I always keep the cabin at 50 to 55 degees throughout the winter.

I plan on staying on the boat New Years (river levels permiting) so I will try to put some temporary insulation on the exterior to see if it helps. Will let you know if successfull, or not.

Max

I cut a piece from those car window shades and put in between the screen and hatch. Haven't had a problem with dripping & can remove if need to.

Roger

Line it with saran wrap so it doesn't stick, if you get some on you, Hoppes gun cleaning solvent will disolve it.
The whole proplem is you have high humidity and it will condense at the coldest spot first. So, lower the humidity or warm the hull and the interior. Neither easily done. If you insulate the hatch the moisture will still condense somewhere else. Maybe on the inside of the hull where you don't see it, but it might do damage, or might not. Do you have insulation there that will soak up the water? You might also try some of the de-humidifier crystals. Good luck, I have a wet boat too, so I know what you mean. --Ed

Thanks all. The hatch is alluminum not plastic, I think I am going to try the foam board with the tape so I can take it out for the summer so as to open the hatch.Might also use a snap on piece of sunbrella,some small pieces left over, to cover and catch any small drips.

Mike

I was at the boat this afternoon getting it ready for New Years party and installed a panel of extruded polystyrene with foam tape around the edges. I installed it in the opening from the inside then pulled the screen under it. It seems to fit snug. The night with tell, its supposed to be in the teens tonight and we will be staying on the boat. I will report back if this worked.

Max

Good deal!

Jeff