I am wondering if your late model Posts have a Sealand odor filter installed. I cannot find one on my 56 and was wondering if the 50's or any other late model Posts had them installed from the factory.
If you have vacuflush heads, they should have one. Follow the vent line from the tank to wherever it goes.
I did that. My holding tank is in the bow so I would suspect the vent is up there too. There is a panel in the back of a closet in the forward stateroom that I might be able to remove, maybe it's behind that.
I am wondering if your late model Posts have a Sealand odor filter installed. My 1998 50 does not, that I know of - but maybe I will learn something from another 50 owner??
Just follow the vent line from the tank to where it exits the hull. If your tank is in the bow, the filter and vent should be close to it. If you have vaccuflush toilets, you need a sealand filter. I removed it on a 58' Azimut that only had a full idiot light that the owners didn't pay attention to, MAN when you flushed a head, you'd have to run for about 75 yards because the smell on the dock was unreal.
Actually, I was surprised to learn some time ago that not all Vacu-Flush heads have filters: RB480Senior Member "Generally most carvers did not have the filters. 20 years on mine without filters. No smell, nothing."
Mine is under the master bed. It lifts up for storage and under that is an access panel to change the filter.
Per Sealand/Dometic rules, they are all to have the in-line filter. Not sure if the Post factory followed the guidelines or not. I hope they did.
Sealand with 3/4" fittings. Boat is Cabo although I think most vacuflush use the same filter. Good luck.