Black Liquid 1991 220 Dancer aft cabin floor

[ag220DA]

I have a black liquid coming up through my aft cabin floor, I think the Black water tank is under the aft cabin, I don't use the Black water tank I have had the boat 6 years and have never used it, I just empty the Tank on the portable toilet.
this just started this year, I'm not sure if there is some sealant coming up through the wood floor above the Black water tank? wanted to see if anyone saw this before I start pulling up the floor.

 

[Lazy Daze]

I have a black liquid coming up through my aft cabin floor, I think the Black water tank is under the aft cabin, I don't use the Black water tank I have had the boat 6 years and have never used it, I just empty the Tank on the portable toilet.
this just started this year, I'm not sure if there is some sealant coming up through the wood floor above the Black water tank? wanted to see if anyone saw this before I start pulling up the floor.

Let's start by clarifying some things, to be sure we know what you have and are working with. A 22' boat is pretty small to have a black water holding tank. Typically, the "holding tank" is just the porta-potty base. That could be either a manual empty or a pump-out. Unless someone made some changes over the years. Please clarify. Plus, tanks don't typically leak UPWARDS - due to that whole gravity thing, you know

It "may" be possible that you have a grey water system. Again, please clarify.

The gas tank would be under the middle section of the mid-cabin.

My first guess would be water/moisture reacting with the wood in the cabin floor panels... the wood is swelling and expelling water. Water will definitely take on a much darker appearance after being "filtered" through rotting wood.

 

[ag220DA]

Let's start by clarifying some things, to be sure we know what you have and are working with. A 22' boat is pretty small to have a black water holding tank. Typically, the "holding tank" is just the porta-potty base. That could be either a manual empty or a pump-out. Unless someone made some changes over the years. Please clarify. Plus, tanks don't typically leak UPWARDS - due to that whole gravity thing, you know

It "may" be possible that you have a grey water system. Again, please clarify.

The gas tank would be under the middle section of the mid-cabin.

My first guess would be water/moisture reacting with the wood in the cabin floor panels... the wood is swelling and expelling water. Water will definitely take on a much darker appearance after being "filtered" through rotting wood.

Lazy Daze, the 1991 220 Sundancer there was an option for a blackwater tank
I do not have a grey water tank all my grey water goes overboard.
it's not water, or dark water the liquid is actually rather thick, it is absolutely coming up through the floor in the aft cabin. maybe it's some type of old Glue used around the fuel tank, or the black water tank behind the fuel tank? I honestly have never seen another 91 220DA with all the options this one has so not sure if anyone has had this issue before. Also the floor wood is not rotten, it's covered in a quite think grey "paint" that seams to have plastic in it, or maybe the floor is actually glassed and there is another filling over that? This really only happens when it's warm out and the Black liquid becomes more fluid when its' cold it is actually quit thick and wont flow.
I'm going to pull the floor up where I can unscrew it and I'll update the post Was just trying to see if anyone had seen this issue before I started.

 

[Lazy Daze]

Hmm. Interesting about the black water tank. I was curious, myself, so I went back and looked through the archives, but didn't see this mentioned anywhere. You mentioned you've only had the boat for 6 years, so maybe a previous owner installed it for a little extra "storage"? Does the porta-potti just gravity drain to this tank?

The paint you are seeing may be a "bilge" gelcoat - it's gelcoat with a wax additive. It's not really necessary in the mid-cabin, but when building the boat it was probably easier to shoot that area along with the bilge before putting the deck on.

But, back to your original question... if it's not liquidy, then yeah, it may be some type of mastik-type material used to seal the panel edges from bilge fumes. Why it's squeezing up - I don't know. Maybe it's at the end of it's life and it's breaking down and oozing out?

There's no glue used around the fuel tank - it's held mechanically. And there wouldn't be anything on the top of the tank - no need for it there. Same should go for the black tank.

 

[BillK2632]

Seems if it was black water it would smell.