In the bilge, I always have about half an inch of water or so. The pump is mounted directly to the bottom (I used 4000UV to adhere the pump base directly to the bilge bottom) but it can't pump it completely dry.
I am not sure where the water is coming from. I had the pump out for a few weeks, and I would clean the bilge with a sponge, but it seemed that about half an inch would always come back. That's all, it didn't get any higher. We had quite a bit of rain, and I have some very small leaks yet to fix, but if the water was leaking in why does it not get higher than half an inch over time?
If the humidity inside the boat is the same as out side, is this an indication that more air flow won't make a difference?