How far is your holding tank from the toilet?

[Chill]

We need to install a holding tank I have been doing some research and was wondering if there is a limit on how far the tank can be from the toilet. As we will be on the Thames we will not require a pump system and will have to pay to pump out so the bigger the tank the better. The place where similar boats have their tanks will only allow an 80ltr tank. There is a large space in at the rear of the starboard cabin which we could fit in approx 150 to 200lts but this is about a 10' run.

Your thoughts please

Chill

 

[jfm]

A ten foot run is fine. I've installed with 10 foot; no problems. The Tecma literature says the tank can be 90 feet away, but that's a bit much imho!

Below is pic of my boat in build. The master cabin WC goes just to left of centre of this pic, and 1/3rd down from top of pic (see the end of the 38mm white pipe) and the pipe runs forward (the straight white pipe that passes under and perpendicular to the yellow pipe) to the black tank which is left foreground of pic. That's about a 12 foot run

You should obviusly arrange it if poss so the pipe is always running a bit downhill to the tank, and if you can't quite do that then imho it makes sense to fit a 1.5 inch valve close to the WC, which you can shut before removing the WC for maintenance, without the contents of 10 foot of pipe pouring out. You can also fit a duckbill non return valve in-line in the pipe

 

[Andrew_Fanner]

Worth doing some checking on diy pump running times for pumpout unless you will always be paying someone to do it. If our tank is full, and its not small but not, I suspect, 200l, the pumpout at Molesey Lock just gets it empty with a bit of a rinse in the available running time. If you are looking for a really big tank it makes sense to need to fund two full pumpouts if you are diy on a timer. I know that Thames Ditton pumpout for you if you ask nicely, as does Chertsey Meads but otherwise I've only used token/card machines with a time limit.

 

[Chill]

A ten foot run is fine. I've installed with 10 foot; no problems. The Tecma literature says the tank can be 90 feet away, but that's a bit much imho!

Below is pic of my boat in build. The master cabin WC goes just to left of centre of this pic, and 1/3rd down from top of pic (see the end of the 38mm white pipe) and the pipe runs forward (the straight white pipe that passes under and perpendicular to the yellow pipe) to the black tank which is left foreground of pic. That's about a 12 foot run

You should obviusly arrange it if poss so the pipe is always running a bit downhill to the tank, and if you can't quite do that then imho it makes sense to fit a 1.5 inch valve close to the WC, which you can shut before removing the WC for maintenance, without the contents of 10 foot of pipe pouring out. You can also fit a duckbill non return valve in-line in the pipe

Thats a good tip fitting a valve close to the WC,

Do you think its worth fitting a fume filter on the tank vent?

Chill

 

[SteveE]

On our F43 the holding tank was near the bow head, and so the aft head must have been a good 25+ foot away, and we never had an issue

 

[jfm]

Do you think its worth fitting a fume filter on the tank vent?

Chill

Definitely. I use the Leesan charcoal ones and I've found they definitely work. I reckon you need them if the vent outlet is somewhere on the hull topsides as it has been on all the boats I've had, but some builders put the vent high in the radar tower* or somewhere and maybe then you don't need them.

I use the Leesan ones. I just looked back at that pic and they don't seem to be installed yet but they will be

*TCM's old Leopard had this feature. There was a hilarious incident, written up on here back in 2003 iirc, where the tank filled right up to the vent and a hosepipe was connected or something and it all sprayed out from the top of the radar tower, in St Tropez.