Pump Out ... SM

Gary Wells

Feeling like a total newbie, we cannot seem to get suction started to empty either holding tank. The tanks ate nearly full as we can look in and see slurry but I'm not sure if there's a drop-in stanchion pipe or some other item I might be missing. There's just a big air gap to look at, and while the pumpout hose does apply suction, it won't draw anything but air. We primed the pumpout hose, made sure there's a good fit but nothing happens. I have to be missing something basic but have had a few other dockmates helping out to no avail. Thoughts?

amelliahona <no_reply@...>


I am surprised you weren't able to pump out your holding tanks in the usual fashion.  The tank and pump out situation was a bit of a mystery to me but I finally figured it out and have posted this diagram in the files section that is "anatomically correct"  as far as I can determine.  

I am glad to update it and repost it if anyone else finds it in error.  

The pump out standpipe goes from the deck fitting to nearly the bottom of the tank.  A vent on the aft face of the black plastic deck mounting fitting allows air to enter the tank (and also acts as an overflow if the tank is overfilled).  So, applying a good seal at the deck fitting with the pump out hose should suck the contents out.  The only reason I can see that this wouldn't work is if there is a leak in the suction standpipe that allows air to enter the standpipe (I believe that standpipe is metal and thus corrosion could have penetrated it), thus breaking the seal and preventing pump out. The suggestion by Alexander is elegant and would overcome this issue.

I have successfully pumped out numerous times using the standard procedure but time will tell if my system will some day suffer a similar fate.

To slow the problems with corrosion and scale deposits in the heads, tanks, and valves; for many years now we have flushed our toilets with fresh water only.  We do this by filling the toilets using the shower head.  I have been reticent to cross connect the fresh water system physically with the toilets.  Every few months I flush the toilet sea water circuits and pumps with fresh water by turning off the sea chest to sea water, filling numerous times with fresh water and rinsing all the sea water circuits with fresh water. 

Just a few thoughts, 


Gary Silver  
s/v Liahona   Amel SM #335 

Gary Wells

Thanks Gary,

I was super puzzled by this one. It appears at first glance that there are no standpipes to draw from. The on deck caps are vented themselves. I am studying the schematics but now that we got the emptied and flushed I'll drop an inspection camera down in there and see if they may have broken. Not a huge deal; just gotta figure out how things work. One of those near-vertical learning curve things :)

Sent from my Verizon Wireless 4G LTE smartphone

Gary Wells

Thanks Joel, 
Much appreciated!  Being new to the boat, and coming from all U.S. breeds prior, it was a puzzler. Solved with a couple of feet of hose and the ever venerable duct tape.  Now we know and now we can adapt :). 

Sent from my Verizon Wireless 4G LTE smartphone

Jim Anderson

Just to add an additional pumpout tip for the SM's that are equipped with the standpipe: Just like on the water and diesel tanks, on the holding tank caps there is a cable attached so that they don't go overboard. When attaching the pumpout suction hose and pressing it firmly into the opening, this little cable coming up and out through the hole will sometimes be enough of an obstruction so as to cause an air leak and prevent the pumpout hose from getting enough suction to empty the tank. To solve this just use a cup and pour a little water around the opening as the hose is sucking. This will stop the hose from sucking air long enough to get the suction hose to start sucking from the tank. Hopefully this is helpful.