Blocked black water gravity drain

mcanderson

Well-Known Member
Joined
24 Sep 2006
Messages
2,149
Location
London/SofF
Visit site
The title says it all. In Nice and no pump out. Ideas?

Do not want to disconnect the drain pipe from the bottom of the tank to discover the block and the contents of the tank.

St Laurent website says they have a pump out facility. Anyone used it?
 
the only real solution (not sure you'd like it though!) is to dive with a mask under the boat with a long screwdriver and poke it in the thruhull and enjoy the output...
mine blocked at some point a few years ago after leaving the boat for two seasons in the filthy port here. Diver wasn't v.impressed...
 
The gravity outflow pipe is usually pretty much in line with the deck pump out. A sewer rod or stiff cable might to the job. I once adapted an old fishing rod for a similar job by removing the rings. Good luck.
 
Unfortunately the seacock has a 90 degree bend so pushing something up is not easy. The solution was an outflow enema with me sealing the area between the hose and the outlet as best as I could then letting water pressure do its work. The fish appeared to enjoy it
 
Unfortunately the seacock has a 90 degree bend so pushing something up is not easy. The solution was an outflow enema with me sealing the area between the hose and the outlet as best as I could then letting water pressure do its work. The fish appeared to enjoy it
I've done similar (gently!) with a dinghy pump - improvise, adapt, overcome 👍
 
But not quite as bad as staying in a marina where everyone's shit is just discharged to the sea!
I was in the marina in Kos one time and their was an Israeli guy berthed next to me. I noticed a nasty pong a few times in the evening. In the morning I figured out where it was coming from. His tank was full and when he flushed the shit etc was spraying out of the tank vent. The side of my boat was streaked with it, as was his. I spoke to him and politely pointed out what was happening. Apparently he knew the tank was full, and was waiting until he left the marina to empty it. "Don't worry, I'm leaving tomorrow, he reassured me". I asked does that mean you won't flush the toilet again. Only at night, he said. I told him what I thought (I may have mentioned pigs and other animals) and went directly to the marina office to complain. He was gone within the hour but I don't know if they just moved him to another berth.
 
mind between the tank and the breather exit, there SHOULD be a smell thing filter (bloody expensive iirc!) if you overfill usually sh!t goes up there and blocks it completely, so if you're worried, I'd replace that first and then see if the vent is blocked
 
I
mind between the tank and the breather exit, there SHOULD be a smell thing filter (bloody expensive iirc!) if you overfill usually sh!t goes up there and blocks it completely, so if you're worried, I'd replace that first and then see if the vent is blocked
I do have a no smell filter, close to deck level. Blockage was in the tank elbow fitting and pipe, a white clay type sludge. I believe this builds up due to saltwater mixing with the tank contents. I switched to fresh flushing a couple of months ago, so hopefully won't happen again
 
I

I do have a no smell filter, close to deck level. Blockage was in the tank elbow fitting and pipe, a white clay type sludge. I believe this builds up due to saltwater mixing with the tank contents. I switched to fresh flushing a couple of months ago, so hopefully won't happen again
I'm on fresh water flush now for the fifth season (iirc) and touch wood black tank is behaving itself :cool:
coming to think, I've not replaced the smell filter for three seasons as there's no smell or anything coming out of the whole system. Vent is near the port cabin portholes, no one has complained so far!
 
We have acsmall pump action sink unblocker. It sucks and blows, and clear most blockages. An in the water job for you, we just unblocked our sink drain with it. Tried it on the bog recently, but in the end we pressurised that with a paddleboard pump. You’d want to be certain you’d done your double jubilee clips up tight though🤣
 
Top