Waste holding tank question

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thethrillisgone

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Hello,
New boat owner here but with years of RV experience. Waste holding tank is a Tektank 277 liter and was installed by previous owner. It never seems to empty all the way, the vent is clear and connected with proper reinforced hose. Had a look at it today and the pump out hose is fitted to the top of the tank as are the others. Inlet, vent.
There is no extension pipe on the pump out fitting that extends into the tank. It is essentially top surface mounted.
Seems to me the pump out hose should be near, or at the bottom of the tank, and that is my question folks.
Should the pump out hose be located at the bottom of the tank?
Thank you in advance for help on this!
Phil
 
thethrillisgone said:
Hello,
New boat owner here but with years of RV experience. Waste holding tank is a Tektank 277 liter and was installed by previous owner. It never seems to empty all the way, the vent is clear and connected with proper reinforced hose. Had a look at it today and the pump out hose is fitted to the top of the tank as are the others. Inlet, vent.
There is no extension pipe on the pump out fitting that extends into the tank. It is essentially top surface mounted.
Seems to me the pump out hose should be near, or at the bottom of the tank, and that is my question folks.
Should the pump out hose be located at the bottom of the tank?
Thank you in advance for help on this!
Phil
Click to expand...
Yes perhaps it has fallen off
Got the Pee shirt
 
The tel tank I have has a dip pipe nearly to the bottom of the tank on both the macerator and the pump out connections.
Tek tanks probably have details if you send them boat type and name and previous owner details.
Perhaps yours has been installed incorrectly. You could take the fittings off and have a look.
 
My tank, when it arrived, had a push in section which extended to the bottom, to pick up the, er, stuff, I realisedthat push in might easily mean drop out. So it’s glued in. I daresay, as others have said, that is your issue. Theres only one way to deal with it. It’s gonna be grim, but the results will be gratifying.
 
I did remove the fittings on the top of the tank which are 1.5". A bit surprised as I checked on Tektanks website and they show dip tubes for 2" only and not 1.5" threads. In my opinion a 1.5" fitting will have a dip tube pretty small for the job it is supposed to do.
Will contact Tektanks for their advice.
Can't really see if a dip tube has fallen in because the tank never really empties out but agree that if it is a push in then it can just as easily fall out.
Thanks again all!
 
Chiara’s slave said:
Personally, don’t we all, but most tanks pump out from the top, at sea or at a pump out facility.
Click to expand...
Really? I’d say most tanks (except for inland boats) only ever empty by gravity into the sea from the bottom drain. The percentage who ever use a pump out facility or even ever open the top hatch must be small.
 
RupertW said:
Really? I’d say most tanks (except for inland boats) only ever empty by gravity into the sea from the bottom drain. The percentage who ever use a pump out facility or even ever open the top hatch must be small.
Click to expand...
Our tank has no provision for a bottom drain. The shore pump out and overboard pump out share the same internal pickup. Opening the top hatch clearly is the nuclear option, especially on Chiara. It’s under the front double berth, where we sleep?
 
RupertW said:
Really? I’d say most tanks (except for inland boats) only ever empty by gravity into the sea from the bottom drain. The percentage who ever use a pump out facility or even ever open the top hatch must be small.
Click to expand...
Disagree, all boats I know of use a pump to empty the waste tank overboard. The exit pipe in the tank is located at the bottom, connected to a 2" hose with an anti siphon loop, a pump somewhere along the pipe and a sea cock. A dump system without a pump would not empty at all underway and possibly fill up.
 
Our boat is equipped with a Tektank and both the ocean pump out line, and the marina pump out line, are on the top of the tank. The ocean line is fitted with a pump on a separate switch and of course, has the sea cock in the center bilge.
She was re-fitted extensively in 2018 and the waste tank was installed under the bed in the main cabin. I have checked both pump out fittings on the tank and there are no dip tubes. Will contact Tektanks once they re-open in January.
I'm told the boat is a Flybridge 43 designed by John Askham and built by Knox marine in 1972 along with Bourne plastics. There isn't a lot of information on the internet about her at least, not that I have found.
 
harvey38 said:
Disagree, all boats I know of use a pump to empty the waste tank overboard. The exit pipe in the tank is located at the bottom, connected to a 2" hose with an anti siphon loop, a pump somewhere along the pipe and a sea cock. A dump system without a pump would not empty at all underway and possibly fill up.
Click to expand...
Ah, that does show my ignorance as a sailing boat person. I thought we’d have loo arrangements in common with motor boats but hadn’t considered that underway the tank wouldn’t just drain to to the sea at motoring speeds.

A typical sailing boat arrangement has the loo outlet going to the top of the tank and and simple bottom pipe going via a seacock to the water. The only control is that seacock and no pump needed as gravity does the work. Seacock open is flush straight to sea, seacock shut means store in tank.
 
thethrillisgone said:
I did remove the fittings on the top of the tank which are 1.5". A bit surprised as I checked on Tektanks website and they show dip tubes for 2" only and not 1.5" threads. In my opinion a 1.5" fitting will have a dip tube pretty small for the job it is supposed to do.
Will contact Tektanks for their advice.
Can't really see if a dip tube has fallen in because the tank never really empties out but agree that if it is a push in then it can just as easily fall out.
Thanks again all!
Click to expand...

This page: Holding Tank Plumbing and Layouts | Tek-Tanks says that fittings are 1.5" which should be fine for pumping out.

Sounds like the dip tube has fallen out, or maybe even left out from the original installation. I wouldn't go looking for it in a full tank, just fit a new one (stick it in). If you can fish the dropped tube out when the tank is empty and had a flush or three, all well and good.
 
RupertW said:
Ah, that does show my ignorance as a sailing boat person. I thought we’d have loo arrangements in common with motor boats but hadn’t considered that underway the tank wouldn’t just drain to to the sea at motoring speeds.

A typical sailing boat arrangement has the loo outlet going to the top of the tank and and simple bottom pipe going via a seacock to the water. The only control is that seacock and no pump needed as gravity does the work. Seacock open is flush straight to sea, seacock shut means store in tank.
Click to expand...
There is no typical system. my mate has a 10 year old Bene Oceanis and that was part of the build - a tank with an open or shut gravity discharge. Mine is a retro fit where a suitable location has to be found and options chosen. On mine the tank location would have meant that a gravity discharge would have been in a position where there was no access to the bottom of the tank or the seacock. So I opted for a pumped discharge and the fittings are all on the top of the tank with dip pipes for the discharge and a separate fitting and pipe for the deck pump out. Tek Tanks website used to have several planning schematics. Edit: see Paul’s post above.
 
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MoodySabre said:
There is no typical system. my mate has a 10 year old Bene Oceanis and that was part of the build - a tank with an open or shut gravity discharge. Mine is a retro fit where a suitable location has to be found and options chosen. On mine the tank location would have meant that a gravity discharge would have been in a position where there was no access to the bottom of the tank or the seacock. So I opted for a pumped discharge and the fittings are all on the top of the tank with dip pipes for the discharge and a separate fitting and pipe for the deck pump out. Tek Tanks website used to have several planning schematics. Edit: see Paul’s post above.
Click to expand...
Ah yours is atypical then
 
PaulRainbow said:
This page: Holding Tank Plumbing and Layouts | Tek-Tanks says that fittings are 1.5" which should be fine for pumping out.

Sounds like the dip tube has fallen out, or maybe even left out from the original installation. I wouldn't go looking for it in a full tank, just fit a new one (stick it in). If you can fish the dropped tube out when the tank is empty and had a flush or three, all well and good.
Click to expand...
This is what I’d do too. Find the dip tube later after a deliberate flush through with as much sea water as possible. Fishing for a drop pipe in a tank full of crap does not bear thinking about.
 
RupertW said:
A typical sailing boat arrangement has the loo outlet going to the top of the tank and and simple bottom pipe going via a seacock to the water. The only control is that seacock and no pump needed as gravity does the work. Seacock open is flush straight to sea, seacock shut means store in tank.
Click to expand...
Mine is like that having fitted it to a mid 1970's boat.
I am wondering about installing a pump out using a tee piece in the outlet to the seacock and then up to deck level, etc. Another project to add to my list ....
 
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