Overboard Discharge

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MikeDH
Posts: 22
Joined: Mon Aug 22, 2016 7:55 pm

Overboard Discharge

Post by MikeDH »

Is there a sea cock at the through hull for the overboard discharge? I can't get to the boat for a while and need to answer this inquiry from a contractor who is going to look into some issues we're having with the head, one of which is that opening the overboard discharge valve underneath the blackwater holding tank doesn't result in gravity removing the contents (off shore, of course). I can't recall seeing a sea cock for that purpose although I didn't specifically look for one when the issue first arose.

Any advice would be appreciated.
wolfe10
Posts: 587
Joined: Mon Dec 11, 2006 2:58 pm
Location: Ft Myers Florida

Re: Overboard Discharge

Post by wolfe10 »

There is a fiberglass tube glassed into the hull.
Between that tube and the black tank is a ball valve. My recollection is that it is ABOVE the water line.
Brett Wolfe
C350 #180
"Vindaloo"
Ft Myers FL
MikeDH
Posts: 22
Joined: Mon Aug 22, 2016 7:55 pm

Re: Overboard Discharge

Post by MikeDH »

Thanks Brett. I would have been surprised to hear there's a seacock I hadn't noticed before. My guess is the ball valve is no longer working, that is it's not opening even when the red handle is moved to the open position.
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russp
Posts: 189
Joined: Fri Apr 01, 2011 5:31 am
Location: Paynesville, Australia

Re: Overboard Discharge

Post by russp »

I am pretty (very) sure that the black water tank discharge is below the water line, but not far below, I would guess the valve position on the upstand is above the water line. It is also possible your outlet drain is blocked at the bottom of the tank and not at the valve. Not fun cleaning out or fixing either!
Russ Peel
Avalon #150
MikeDH
Posts: 22
Joined: Mon Aug 22, 2016 7:55 pm

Re: Overboard Discharge

Post by MikeDH »

Thanks Russ. Now that I've confirmed there's no seacock where the discharge exits the boat, I think I'll let the contractor figure out whether the hang up is at the ball valve, the bottom of the tank (or elsewhere).
Triumph
Posts: 256
Joined: Thu Nov 03, 2005 7:34 am
Location: Tampa, Fl

Re: Overboard Discharge

Post by Triumph »

I've had this happen twice. If the boat sits for a while, sludge settles across the bottom of the holding tank and completely blocks the drain. I opened the valve, got a thin rod, swan to the through hull and poked it and then swan like hell to get out of the way of the brown cloud. I suggest you do not do this in a marina.

So it may very well be this issue. After doing this, I went to the RV store and bought some tank cleaner. I've also read about using fabric softener and hot water to loosen any sludge.

Bill
TRIUMPH
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digitalvillager
Posts: 36
Joined: Mon May 14, 2012 1:23 pm

Re: Overboard Discharge

Post by digitalvillager »

I talked to the manufacturer of the ball valve and they gave me some good information: The red handle will slide off with just a little resistance (no screw or bolt holding it on). The only thing that can happen is that the keyway on the handle or the key on the shaft could get stripped. If you can rotate the handle and pull the handle off and the key/keyway are intact and rotated, then the valve is operating correctly.
There is a 45 degree angle at the hull that a shaft will have to pass before the tube goes vertical, so be careful not to shove a stiff rod through the side of the tube trying to get it to make the turn as the 45 is below the water line.
I had the tank pumped and plan to send up a hose with a small jet nozzle on it to blow the blockage loose. I'll report the result after this weekend.
Charlie & Jeanne Monroe
PO Hull #285
Amelia Island, Florida
MikeDH
Posts: 22
Joined: Mon Aug 22, 2016 7:55 pm

Re: Overboard Discharge

Post by MikeDH »

Thanks to both for the additional info. I'll slip off the red handle to see if the ball valve is working next time I'm at the boat. If so, it seems a pretty good bet sludge is clogging the bottom of the tank. I read in another thread some have had success with septic cleaner from Walmart in resolving that issue.
JohnNorton
Posts: 59
Joined: Thu Oct 13, 2011 12:27 pm

Re: Overboard Discharge

Post by JohnNorton »

Mike: On C350 the discharge from the holding tank does get blocked up easily (even non-boat specific TP will do it). If you do not haul out the boat to solve this you can go out to sea 3+ miles and shove heavy gage, stiff wire up the discharge to eventuially loosen the blockage. I'd sure pump out the tank a few times, refill with water only- and repeat, repeat, then try this. You'll have to have the red ball valve in the open position- and be ready to get upstream quickly. Have perhaps 5 gallons of hopefully only water in the holding take before you do this. You'll know when the blockage is cleared !
MikeDH
Posts: 22
Joined: Mon Aug 22, 2016 7:55 pm

Re: Overboard Discharge

Post by MikeDH »

Thanks John. Good advice. If I go that route I think I'll try a plumber's snake and/or heavy gauge wire. I'll be hauling the boat briefly in August so I can try it while on the hard.
wolfe10
Posts: 587
Joined: Mon Dec 11, 2006 2:58 pm
Location: Ft Myers Florida

Re: Overboard Discharge

Post by wolfe10 »

I think I would try a hose (scrap, not one you will use for potable water). Stick it through the deck pump out plate. Turn on the hose after working it around until it feeds into the drain area.

Were that not to work, insert the hose from below/the thru hull and "blast it".
Last edited by wolfe10 on Fri Jun 21, 2019 6:48 pm, edited 1 time in total.
Brett Wolfe
C350 #180
"Vindaloo"
Ft Myers FL
MikeDH
Posts: 22
Joined: Mon Aug 22, 2016 7:55 pm

Re: Overboard Discharge

Post by MikeDH »

Another good suggestion. Thanks. I can try that one before the haul out to at least see if I can get the hose to feed into the drain area. My plan now leading up to haul out is: use some septic tank cleaner to try to soften/disolve sludge; confirm ball valve is operating by removing handle; feed old hose through deck plate into draIn area to confirm I can find it; decide on next steps based on results.

I'll report back with results as I go along. Thanks again to all for the suggestions.
nybor
Posts: 248
Joined: Sun Jan 06, 2013 7:55 am

Re: Overboard Discharge

Post by nybor »

Been there, done that. We sailed to Cuba in December and while the red valve was open, it wasn't discharging. At the marina, I opened the access and.......ever seen a S_ _ _ volcano?

Anyway, got back to Venice and tried the plumber's snake, etc. etc. Finally, I covered the toilet bowl with a plastic sheet and opened the discharge valve and had a pump-out. After a couple of minutes all of a sudden clean saltwater came up through the pump-out hose. So far it has been fine. However, as suggested I did fill and empty the tank multiple times with fresh water.

dave
Nybor

ps before sealing the toilet, the pump-out sucked air thru it, so it killed the pump vacuum.
MikeDH
Posts: 22
Joined: Mon Aug 22, 2016 7:55 pm

Re: Overboard Discharge

Post by MikeDH »

Interesting. Thanks. Seems like many of us have experienced this issue at one time or another. I may try the plastic seal approach once I confirm the ball valve is operating properly and after letting the septic cleaner loosen up the sludge. I'm also curious to see if I can find the drain opening at the bottom of the tank with an old hose fed through the deck plate, but a clear advantage to the plastic sheet/pump-out approach is it doesn't involve anything pouring out of the underwater discharge.
rrdimattia
Posts: 5
Joined: Tue Aug 15, 2006 8:34 pm

Re: Overboard Discharge

Post by rrdimattia »

I was able to clear this bye hooking up to the vacuum anything to take in a normal fashion. And then have someone put their finger over at the air vent on the side of the hull
Then open and close the red valve which is the discharge to overboard and it should suck sea water backwards to that valve and clear the blockage and in the process you should not really leak any sewage into the sea water
Ralph R. DiMattia
2005 Catalina 350
"EGINDA II"
York River Yacht Haven
Sarah's Creek
Gloucester Point, VA
zman18
Posts: 60
Joined: Mon Sep 30, 2013 11:37 am

Re: Overboard Discharge

Post by zman18 »

We had the same issue and using a plumbers snake while in our dingy alongside to dump the tank. We then bought a box of septic tank cleaner and filled the tank part way with water and a little of the cleaner. Left this for a couple of weeks then did a discharge. Worked fine and has been good for the past couple of years.
John Zoda
Compass Rose
Hull# 484
cuthbert
Posts: 86
Joined: Fri Apr 27, 2012 1:20 pm

Re: Overboard Discharge

Post by cuthbert »

I too ran into this problem. I think it was caused by non marine TP, but the gravity discharge stopped working.

Steps to resolve:

1) Pump out to empty tank.
2) Fill tank with water, leave the valve open.
3) Take a standard wash down hose with a good nozzle that can give a tight jet with some good pressure and insert into the discharge (which is just a few inches below water line)
4) Blast the water up the discharge tube and you will know the second it clears (and it took about a second) as all the water drops out and bits of tp also. Really easy to resolve and having pumped out and filled with clean water I didn't have concerns about the problem being resolved insitu.

Prior to that I had tried a few pump outs and pushing water in through the deck pump out, also a few attempts at various products that disolve RV/marine head contents. I had also tried a thin metal rod about 3 ft long which pushed past the obstruction ok but did not clear it. I climbed onto a kayak next to the boat to reach the discharge pipe but in a slip I think that pulling the boat back 3ft and then tie tighter to the port side would allow the pipe to be reached from lying down on the slip finger.

But in summary, if the tank is filling and the valve moves through 90 degrees ok but without the reassuring whoosh of emptying, then the water jet up the pipe seemed to me to be an instant cure.
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