How about a shower sump installation (I believe the stock setup drains into the bilge) ?
at the transient dock you can go ashore for a shower. So why add the moisture to the inside of the boat?
Guy
We liveaboard our E-39B and our shower drains into the bilge. There is a 1" line that goes all the way back aft to the deepest part of the bilge, which is under the engine. We shower on shore when they are available. I will put in a seperate sump someday, but for now the water goes straight to the bottom of the bilge, so as not get get any other area of the bilge wet. Except for the tiny bit of water under the bilge pump, our bilge is clean and dry. We also keep a strainer in the shower drain so nothing gets in the bilge.
The good news for us Oregonians is that we have nice tie-ups available at concrete floats up and down the Columbia River and on many larger lakes, all built with our boating registration $$ and at zero cost to the state general fund...
OTOH, those docks never have showers unless located adjacent to a city waterfront with their own shower building, like the one at St Helens, OR.
Every boating area probably has its plusses and minuses, though.
As to moisture, we really dislike the mess inside the boat from showering.
Loren