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Pump out on Hunter

Apr 21, 2019
17
Hunter 37.6 Vancouver
In order to use a pump out station do you have to close the through haul valve after the Macerator , or can you leave the valve in the open position. Thanks for any advice
Thanks everybody for the advice. Emptied the tank and found the Macerator was not working.
Ordering a new pump. Also needed through hull closed
 
Last edited:
Oct 22, 2014
12,813
CAL 35 Cruiser Portland OR, moored EVERETT WA
ACE... Let's think this through. You have the Thru Hull open. The Macerator is open to the Holding tank. You open the pump out and start to suck out the contents. Seems to me that the contents will get sucked out and then the sea water will start to in flow and you'll soon be sucking marina water which is trying to fill the holding tank from beneath the boat.

I'd close the thru hull for the Macerator.
 
Feb 21, 2013
1,449
Hunter 46 Point Richmond, CA
Assuming your system looks like the diagram below, make sure the thru hull valve downstream of the macerator is closed. That is the same set up on each of my two sailboat holding tanks and the thru hull valves on the discharge of each macerator are kept closed.

Canadian Yachting Regs: Guide to Sewage Discharge Regs

1594744770552.png
 
Oct 22, 2014
12,813
CAL 35 Cruiser Portland OR, moored EVERETT WA
Of course you have a clean and large vent hole so that will be trying to compete by adding air into the holding tank.
 
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Feb 10, 2004
3,305
Hunter 40.5 East Greenwich, RI
The macerator is a positive-displacement pump with a rubber impeller that seals the pump chamber. IMHO if you can pull water through that pump then you need to rebuild the pump.
 
Dec 2, 1997
7,752
- - LIttle Rock
I hate to break it to you, Rich...but a macerator pump that doesn't need rebuilding installed below waterline won't block slow seepage. I've seen that fill a tank to the waterline on a boat left sitting with the thruhull open. If it can't block slow seepage, water CAN be pulled through it....slowly, and maybe not much during a pumpout, but it can happen.

--Peggie
 
Dec 19, 2006
5,656
Hunter 36 Punta Gorda
Keep thru hull closed always here in Florida unless out miles from shore but don’t want mistake dumping waste over board will be big fines.
Nick
 

jviss

.
Feb 5, 2004
4,597
Tartan 3800 Westport, MA
In most no-discharge zones that I am aware of it's the law that one not only close the seacock but that also that it be secured by padlocking it, removing the handle, or securing it with a non-reusable wire tie.
 
Last edited:
Jun 1, 2009
1,279
Hunter 49 toronto
Respectfully, I believe your drawing is somewhat incorrect technically.
To the best of my knowledge, holding tanks never have discharge fittings at the bottom of the tank.
these connections would be made via a dip tube through the top of the tank.
The reason for this is that you never want the possibility of a slightly leaky fitting dumping sewage into your bilge.
 

Mikem

.
Dec 20, 2009
709
Hunter 466 Bremerton
Respectfully, I believe your drawing is somewhat incorrect technically.
To the best of my knowledge, holding tanks never have discharge fittings at the bottom of the tank.
these connections would be made via a dip tube through the top of the tank.
The reason for this is that you never want the possibility of a slightly leaky fitting dumping sewage into your bilge.
Hmmm. On my daughter's previous 1982 C-30 the discharge line (the line to the deck pumpout fitting) was at the bottom of the tank. The "discharge" from the head to the holding tank was near the top of the tank. In other words the drawing referred to correctly mimicked the system on the C-30. That said, your description is a much better design for the reason you list.
 
Feb 21, 2013
1,449
Hunter 46 Point Richmond, CA
The schematic drawing is "conceptual" and may have a dip tube not shown on sailboat manual plumbing drawings.
 
Jul 6, 2017
140
Hunter H 41DS Hampton, VA
I hate to break it to you, Rich...but a macerator pump that doesn't need rebuilding installed below waterline won't block slow seepage. I've seen that fill a tank to the waterline on a boat left sitting with the thruhull open. If it can't block slow seepage, water CAN be pulled through it....slowly, and maybe not much during a pumpout, but it can happen.

--Peggie
Agreed. just try putting you boat on the hard for a repair with a full tank and leave the valve open. The boat will seep black water.
 
Dec 2, 1997
7,752
- - LIttle Rock
To the best of my knowledge, holding tanks never have discharge fittings at the bottom of the tank.
If you check marine catalogs, you'll find that the "standard location" for most off- the-shelf tanks and OEM tanks on production boats is all fittings in one end of the tank, inlet high, discharge low, and vent high in a corner for as long as holding tanks have been required (which has been 40 years now). Discharge on top with a dip-tube is actually a fairly recent innovation (I first head of it and began recommending it in the mid '90s) seldom used by OEMs 'cuz it costs a bit more and because additional clearance of up to 5" above the tank is needed for hose fittings--space that isn''t always available.

On top with a diptube is my favorite way to do it when there is enough clearance above the tank 'cuz it eliminates standing sewage in the tank discharge line...and whether the discharge fitting can go on the top or not, I also recommend putting TWO discharge fittings in a tank that's plumbed to dump at sea 'cuz it eliminates the need for a y-valve in the pumpout line.

--Peggie
 
Jun 1, 2009
1,279
Hunter 49 toronto
If you check marine catalogs, you'll find that the "standard location" for most off- the-shelf tanks and OEM tanks on production boats is all fittings in one end of the tank, inlet high, discharge low, and vent high in a corner for as long as holding tanks have been required (which has been 40 years now). Discharge on top with a dip-tube is actually a fairly recent innovation (I first head of it and began recommending it in the mid '90s) seldom used by OEMs 'cuz it costs a bit more and because additional clearance of up to 5" above the tank is needed for hose fittings--space that isn''t always available.

On top with a diptube is my favorite way to do it when there is enough clearance above the tank 'cuz it eliminates standing sewage in the tank discharge line...and whether the discharge fitting can go on the top or not, I also recommend putting TWO discharge fittings in a tank that's plumbed to dump at sea 'cuz it eliminates the need for a y-valve in the pumpout line.

--Peggie
Peggy
The only time I’ve seen (in recent production boats) drains at the bottom are on Beneteaus, jeanneaus, where they have gravity dump tanks. These are typically prettty small tanks compared to what you can fit under a floor or berth.
These tanks are found a lot on charter boats, and they instruct the “captain”, to open the lever when the tank guage reads full.
Well, guess what happens? They just open it, and leave it that way for the whole charter, irrespective if the boat is anchored in a tranquil bay, or offshore.
And the charter based love this, because the boats comeback with empty tanks, and no macerator pumps to ever repair.
On my CS 33, the drain was at the tank bottom. Complete disaster. (I won’t elaborate)
Thanks for your informative posts!!
 

jviss

.
Feb 5, 2004
4,597
Tartan 3800 Westport, MA
Respectfully, I believe your drawing is somewhat incorrect technically.
To the best of my knowledge, holding tanks never have discharge fittings at the bottom of the tank.
these connections would be made via a dip tube through the top of the tank.
The reason for this is that you never want the possibility of a slightly leaky fitting dumping sewage into your bilge.
My 1984 Catalina 36 had the holding discharge at the bottom.
 
Jan 12, 2011
882
Hunter 410 full time cruiser
my holding tank has both the "drain" for the macerator pump and the pump out at the bottom of the tank
 

Mikem

.
Dec 20, 2009
709
Hunter 466 Bremerton
Respectfully, I believe your drawing is somewhat incorrect technically.
To the best of my knowledge, holding tanks never have discharge fittings at the bottom of the tank.
these connections would be made via a dip tube through the top of the tank.
The reason for this is that you never want the possibility of a slightly leaky fitting dumping sewage into your bilge.
Both holding tanks on my 2003 H466 have the discharge at the bottom.
 
Feb 21, 2013
1,449
Hunter 46 Point Richmond, CA
Ditto Mikem..............both holding tanks on my 2005 Hunter 46 have the discharge at the bottom
 
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Jul 6, 2017
140
Hunter H 41DS Hampton, VA
All 5 connections on our 2006 H41DS tank are on the top of the tank:
1. macerater pump dip tube
2. drain/suction line dip tube
3. bow head discharge
4. master head discharge
5. air vent