Looking for tank discharge valve

dgadee

dgadee

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Installing a black water tank and don't have too much space between bottom of tank and the outlet seacock so looking for a discharge valve which can be fitted directly to the waste tank. I've perused various retailers but can't see what I want (most 1 1/2" tank outlets are 90 degree bends). The highlighted valve is what I am looking for:

Capture.jpg

Any suggestions?
 
Just use a standard 1 1/2" DZR ball valve with a skin fitting through the tank and a spigot hose tail. That is what I did, but you will find the total assembly rather long and you may not have space.

It is common not to have a valve at that point now but rely on the seacock. That is what I have had on 2 Bavarias. The downside of the valve on the tank is that it is more prone to blockages and I made sure the inspection hatch on both tanks I had made (one for a Bavaria 37 and the other for an old wooden boat) was immediately above the outlet.
 
Tranona said:
It is common not to have a valve at that point now but rely on the seacock. That is what I have had on 2 Bavarias. The downside of the valve on the tank is that it is more prone to blockages and I made sure the inspection hatch on both tanks I had made (one for a Bavaria 37 and the other for an old wooden boat) was immediately above the outlet.
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That surely won't let you discharge without going through the tank? Or am I misunderstanding? I can understand why you wouldn't want a valve on the the tank but wouldn't you then need two diverter valves, giving the same problem?
 
dgadee said:
That surely won't let you discharge without going through the tank? Or am I misunderstanding? I can understand why you wouldn't want a valve on the the tank but wouldn't you then need two diverter valves, giving the same problem?
Click to expand...

You don't have a pump to empty the tank, so presumably it empties by gravity ? If that's the case, you don't need the valve at the bottom of the tank or the Y diverter. You just pump to the tank and if at sea leave the seacock open, close it when in the marina/river.
 
PaulRainbow said:
You don't have a pump to empty the tank, so presumably it empties by gravity ? If that's the case, you don't need the valve at the bottom of the tank or the Y diverter. You just pump to the tank and if at sea leave the seacock open, close it when in the marina/river.
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Exactly. A common and simple arrangement where tanks are installed above sea-level.
 
I used an expensive plastic discharge valve from Tek Tanks precisely because I didn't want the holding tank waste backing up against the seacock, which on our boat is in a difficult to access location (the logic being that I'd rather deal with a blockage where I can get at the pipework easily than one where I'd have to make like a contortionist)

It's also lockable thus meeting the requirements I understand to exist in some Furrin Parts

It was, however, about £90 :0
 
dgadee said:
Am I being anti social in flushing out my widdle in a marina? At that age ....
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You don't = just close the seacock so everything stays in the tank until you get to sea or the pumpout station.

Just think of the tank as an enlarged hose. It is the simplest system and it is clearly best if the seacock is easily accessible. You could put in a Y valve system to give the option of pumping either to the tank or direct to the seacock but you need either two valves or a dedicated seacock for the tank. Extra complication and rarely enough room particularly on a retrofit.

So, keep it simple - just make sure you place your inspection hatch over the outlet and have a decent size vent.
 
My tank is in fore peak bellow sea level. Originally only discharge om tank was via on deck pump out.
The whole system was blocked with calcium scale.
I replaced all the hoses an valves and added a 2nd Y valve and pump to OB on discharge side.
one advantage of not having a valve in bottom of holding tank, Its in the bottom of aft side. The hose fitting is straight and screws in. I was able to blank it, After getting the tank pumped out. without a nasty mess.
While changing all the hoses and connections.
 
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Tranona said:
So, keep it simple - just make sure you place your inspection hatch over the outlet and have a decent size vent.
Click to expand...

I think I might well have to do this - that was my original plan but it seemed such a simple step to implement the switchover system. It's beginning to look not so simple.
 
If you are happy with a plastic fitting you can get 45 degree plastic hosetails and then fit the valve or seacock to that ( if indeed you want a valve at that point)
 
Well, I kept it simple. In at top and out of bottom of tank. Disaster.

Three days use and it turned out nothing was leaving the tank. No way to empty it except by removing pipe from seacock, putting wire up and holding a bucket underneath. Not pleasant.

Seems to be my partner has a high paper to pump ratio. I have told her before ...

I thought this was supposed to be the trouble free solution?
 
dgadee said:
Well, I kept it simple. In at top and out of bottom of tank. Disaster.

Three days use and it turned out nothing was leaving the tank. No way to empty it except by removing pipe from seacock, putting wire up and holding a bucket underneath. Not pleasant.

Seems to be my partner has a high paper to pump ratio. I have told her before ...

I thought this was supposed to be the trouble free solution?
Click to expand...

Strange. Our straight through gravity system is working perfectly. Was the blockage in the tank or the pipe?

I ask because I fitted a (rather expensive it must be said) discharge valve on the tank outlet precisely to avoid a build up of loo paper and, er, stuff, backing up the hose from the seacock
 
Bru said:
Strange. Our straight through gravity system is working perfectly. Was the blockage in the tank or the pipe?

I ask because I fitted a (rather expensive it must be said) discharge valve on the tank outlet precisely to avoid a build up of loo paper and, er, stuff, backing up the hose from the seacock
Click to expand...

In the tank, it seems. Simple vetus 40l tank with vetus fittings.
 
We have the simple vertical system from pump-out opening at the top down through holding tank to seacock at the bottom with no other valves. We've never used a pump-out but that means we could rod straight through from the top.

But also we use the Greek way of small lined pedal bins in each heads so no paper goes in and after nearly a decade no blockages either.
 
dgadee said:
Well, I kept it simple. In at top and out of bottom of tank. Disaster.

Three days use and it turned out nothing was leaving the tank. No way to empty it except by removing pipe from seacock, putting wire up and holding a bucket underneath. Not pleasant.

Seems to be my partner has a high paper to pump ratio. I have told her before ...

I thought this was supposed to be the trouble free solution?
Click to expand...

We have the same system and the only times we have ever had any problems was when the boat had been out on charter and the rules were not followed:

a) Only soft multiply toilet tissue to be used in the toilet. No other paper of any sort whatsoever.

b) One separate sheet to be used at a time. If in real difficulty, then two sheets folder over each other. Never any more.

Richard
 
Ah, we strictly forbid "fancy" toilet tissue (Andrex and the like). Cheapest supermarket own brand stuff, preferably, if available, recycled.

Unlike the fancy tissue it dissolves away to nothing in the tank within hours

Never had to impose a limitation on how much tissue is used, other than "not too much"

(My golden rule of "if you block it, I'll hand you the tools and tell you how to unblock it" might also be a factor!!!)
 
RichardS said:
We have the same system and the only times we have ever had any problems was when the boat had been out on charter and the rules were not followed:

a) Only soft multiply toilet tissue to be used in the toilet. No other paper of any sort whatsoever.

b) One separate sheet to be used at a time. If in real difficulty, then two sheets folder over each other. Never any more.

Richard
Click to expand...

Ha! I'll give you her mobile number and you can break the news to her.
 
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