Holding tanks

[Guest]

I hate them, never used one, never will. (Did that sound like Denny crane?)

 

Have a read of this

 

http://www.raritaneng.com/information/n ... _Neale.htm

[Elenya 33]

We have a 50 liter tank on our current yacht. This lasts two of us up to a week if we are carefull (ie use shore facilities and ionly flush till out of sight). The tank is a gravity discharge and works fine. Cheap and easy to fit and use. We have a 40 foot boat (although the tank on our 32 foot boat was 150 litres! in the bilge). This type of tanks helps when you spend an overnight or few days in a bay. We do have deck pump out but have only used this a few times.

 

I have wathched the move to no discharge areas with some interest. It is I believe being looked at in Northland for the Bay of Islands, but cannot confirm this. I'm sure some proactive and sensible use of tanks by boaties would help in stopping a large hammer being used to crack this problem. No one likes swimming in s..t.

 

Mind you the amount of sewarage from vessels may be small compared to the amount that flows out into the Harbour during periods of high rain in Auckland.

[Guest]

Or if there is an outgoing tide at 3 am in Whangarei river. That is when they let it go if there is too much to process.

[wheels 543]

I don't have an issue with having a Holding tank. I have one, I like it, I would fit one again.

I do agree with much of the article too though. There is always something wrong with the pump out facility. Having to suck out the tank is a pain and if not careful, can be a little messy.

We simply discharge to sea when we are far enough away from the shore and in deep watr and no where near a marine farm or other boats. The advantage of ours is that the stuff is macerated before going into the tank and macerated when pumping out. All our sinks and showers drain to the same holding tank. So a lot of fresh water goes in as well. When the pump is discharging, all that comes out is a liquid like dark Tea. No solids or paper to be seen. If we have guests on board and have sat for a few days, we can hold a fair amount of waste. The tank is 2000ltrs for a starter and we have probably had maybe 1000ltrs at most. The problem with that is when we discharge, that is a 1000ltrs being discharged as against a toilet bowl being discharged. The problem with the toilet bowl being discharged is that it often is a little more 'concentrated" than the 1000ltrs was in our holding tank.

I think boats should have a holding tank, just so as you can discharge when you are away from the shore and hold it all when rafted up or close to a beach or farm or what ever. But I don't think we need to get as carried away as the US with having to get so many miles off shore and have 1,2 & 3 categories for treatment processes.

[Guest]

I'm thinking of pumping all my waste to the holding tank Wheels. Do you have any problems with smells/other things getting back up any of the plumbing?

Do you use water traps or other methods to stop this?

 

I like this idea as the chance of back syphoning seawater to the shower tray etc is eliminated, and quite a few less skin fittings.

[wheels 543]

Yep S traps on every basin. The shower sump pumps up to a S trap and then down the same Basin drain. The Toilets use a small amount of water in the bowl to seal off.

The breather has a carbon filter.

[Guest]

That is what I was thinking of doing, but it better to know it works before trying.

[wal 27]

I think the technology has advanced, as has the availability of good tanks, that it's not all that scary anymore.

 

The (solely) pump out variety doesn't turn me on much - the empty at sea gravity option being rather more attractive

 

"turned on" "attractive" talking about holding tanks?!?

 

 

Gad - it's the heat......

[Guest]

I definitely want to try the composting airhead thingy a la Bogan, and not because it is environmentally friendly, I honestly think it is a better solution.

[wheels 543]

Yeah squid, I am keen at looking at that sort of thing too, but I still can't get my head around how it works efficiently on a boat.

the empty at sea gravity option being rather more attractive

Wal it depends on the situation. I have a big live aboardable type boat with Aft cabin/Ensuite one end and the other Toilet and shower the other end and Galley in the middle. If we were cruising, we would be much much more energy and water efficient. But at the mo, lots of water goes into that big cavern of a holding tank each day. Dawn also has a Saltwater tap at the galley sink and that equates to a lot heading for the tank as well. Then add to that, the tank is below water line. So we have to pump out. But the Gravity idea works brilliantly, especially in smaller boats. Certainly the old KISS approach is best when it comes to waste disposal. The more complex, the more that can go wrong and it always goes wrong at the worst possible time.

[Fusion 0]

I have a simple option that happened by coincidence. The toilet flushing water is picked up from a T into the grey water out, This is just at the skin fitting valve. If I close the skin fitting I can pump all grey water through the toilet in to the holding tank.

[wal 27]

Yeah squid, I am keen at looking at that sort of thing too, but I still can't get my head around how it works efficiently on a boat.

the empty at sea gravity option being rather more attractive

Wal it depends on the situation. I have a big live aboardable type boat with Aft cabin/Ensuite one end and the other Toilet and shower the other end and Galley in the middle. If we were cruising, we would be much much more energy and water efficient. But at the mo, lots of water goes into that big cavern of a holding tank each day. Dawn also has a Saltwater tap at the galley sink and that equates to a lot heading for the tank as well. Then add to that, the tank is below water line. So we have to pump out. But the Gravity idea works brilliantly, especially in smaller boats. Certainly the old KISS approach is best when it comes to waste disposal. The more complex, the more that can go wrong and it always goes wrong at the worst possible time.

 

 

Yeah - owning 30' race/camping boat I tend to think for my situation

[Guest]

The water from the shower is what is making me think putting the grey water into the holding tank is a good idea.

The suction from the tray is obviously below the waterline. This fact, combined with my low freeboard makes the chance of syphoning back into the showertray a when not if situation I think.

Not too keen on using a check valve in this situation either with all the soap gunge that builds up in grey water lines.

I'm not going to manage 1000L though wheels. My boat displacement is 6 tons not 16.

[Murky 1]

I'm not going to manage 1000L though wheels.

1000L = one cubic metre, is that right? I am not sure what is harder to imagine - having that much interior space to spare, or that much...contents.

[Guest]

Yep, that's quite a few poo's!

[Murky 1]

Although well diluted and twice macerated as Wheels has pointed out above.

 

It was just the capacity that suddenly struck me. If we had a spare cubic metre I think we would be calling that the owner's cabin.

[Guest]

The 60fter I brought back from Aussie had 2 x 1000lt fuel tanks, 3 x 1000lt water tanks and 2 x 1000 iky water tanks.

 

Hard case pulling up the the dock and asking for 2 tonnes of fuel and 3 tonnes of water please.

 

We don't have a holding tank so are careful what's done where but I'll stick one in when she comes out. Due to space it'll be 10lts max so no curries for us while aboard Tank up on a wall, knot a wal, and gravity feed out.

[Murky 1]

Normally I would let you make your own mistakes but I have to say that we have had a 20lt for the past couple of Christmase cruises and have very much had the experience that its capacity is dictating what we do i.e. with four of us (kids aged six and eight, who aren't really doing anything I wouldn't expect), if we were to come into a bay at 2pm, even with careful use we would be in marginal territory by nightfall.

 

This has required us to go out at times or in conditions that we would otherwise have avoided. Not to mention the overflow situation on to the kite sheets.

 

I spent a lot of time measuring up while we were away this Christmas and think we could get up to 40-60lt, although unfortunately not in an off-the-shelf model. The original was installed in the most obvious position on a bulkhead but finding a way to get more space has not been overly hard. I also have two other hard-won lessons which I would share with you.

 

I guess in your case it will not be being pushed anywhere near its capacity for 98% of the time but now my advice would be always go bigger bigger bigger.

[Guest]

Guess they are still new here, just wait till they start to leak/split/dribble sh*t into your bilge to find three weeks later.

[Grinna 2]

We have a holding tank, but I haven't used it yet. Previous owner had it installed but he couldn't explain its use as he had never used it in the 4 years he'd had it in the boat (*cough useless bugger cough*).

 

Need to pull up floorboards, trace out pipes and valves and work out how to use it and if its all serviceable. Suspect its a double macerator system (macerated going into the tank and again going out) but unsure if holding tank pump works .... don't want to start filling it if there's no way to empty it.