Dog, I have to disagree with you on this one. Condensate would be pure water if it wasn't mixed with the air inside the boat, but it is.
The air that mixes with the water will contain minute bits of whatever is drifting around in the air, including dead skin cells, mold spores, etc. What you have is a pre-made mix of biological debris that will quickly turn into a 'science project' in the drip pan of an A/C unit.
Getting the condensate overboard is a must if you don't want a sour smell.
Cap'n Dave, I don't know how your a/c unit is mounted, but if you have a bit of drop from the drain pan, you might do what I did on Breeze. I had a very small plexiglass box made up at the local plastics shop. It has a removable top for access inside it. Inside the box is a small, very cheap bilge pump
and an electronic bilge pump
switch. the plumbing was pretty straight forward. I put a cheap plastic thru-hull fitting high on the box and attached a hose from there to the drip pan of the a/c unit. The outlet from the pump
goes out through a piece of hose that I used 5200 to hold in place. Then I put one of the small, very lightweight check valves just outside of the box (from Whale. They're made for bilge pumps
) and tied the other end of the hose into the downhill side of another bilge pump's output.
This made a huge difference inside the boat. It got rid of a high percentage of the musty smell from the a/c.
The other thing you can do is throw a bromide tablet, one of the small ones used for Jacuzzi tubs, into the condensate catch box. This will kill the critters that might otherwise start growing in there. They last quite a while, since they're really designed for hot water. They leech enough stuff out to kill what grows and the concentration isn't high enough to damage anything inside the box.