gray water storage and reuse for flushing

[jfm]

Well, when I fitted Tecma WCs and black water tank (which the boat originally didn't have), I also got rid of sea water flush, fwiw. And I'm glad I did.
I accept it's not a compelling reason, but not a caprice, either.
My WCs, T-valves, pumps, tank are now in MUCH better shape, after almost 10 years, compared to how the original equipment looked like after just 4.
If I would/could spec my dream boat, I would get rid of ANY sea water:
1) just two sea chests, interconnected for redundancy;
2) engines, gensets, a/c, anchor chains wash - all feeded from the chests;
3) some mean of deviating the chests intakes (electric valves?), in order to fill them from the fresh water tanks rather than from the sea;
4) upon arrival in a marina, just switch the chests intakes, and run every equipment for a minute.
Job done, the boat when not used would have ZERO sea water inside her.

I love that system MapisM. You should patent that. Brilliant. This is going on the list for my next boat.

One tiny detail: I would have two anchor wash pumps: one seawater and one fresh. Then if I knew I had plenty of freshwater in my tanks and I was going back to the marina that night, or if it was my last anchor retrieval before leaving the boat for several weeks, I would use freshwater to wash the anchor chain

 

[EME]

Okay okay I give in . I cannot think of a rational argument not to have sea-water flush, at least in clean seas. I still don't like the idea though, and will stick with my freshwater flushing, but I accept that the reasons for this are capriciousness not science!

Unlike you JFM.!

Fish P and c*** in the sea. You just dont want to introduce the stuff for exactly the purpose you want to use water for in the first place. QED

 

[BartW]

I would use freshwater to wash the anchor chain

agree,
again something I would have expected on a Canados (fresh water in stead of salt water anchor shower)



its 26°C right now here in Belgium,
lets go outside and do some boating .....
I will.

 

[MrB]

Wouldn't it just pay to have a water maker onboard? I guess the Sqn.78 has one?

 

[MapisM]

One tiny detail: I would have two anchor wash pumps: one seawater and one fresh. Then if I knew I had plenty of freshwater in my tanks and I was going back to the marina that night, or if it was my last anchor retrieval before leaving the boat for several weeks, I would use freshwater to wash the anchor chain

Good point. And there's no need to use two pumps, either - redundancy aside, of course.
Just think of "my" system above (apropos, thanks for the appreciation. You don't seriously think it could be patented, do you? ):
If the pump sucks water from the chest, it normally works with sea water. Upon arrival, at least the pump circuit will be flushed with fresh water anyway, but not the whole chain of course.
For the "last anchor retrieval" case, it would be sufficient to connect the pump hose to the chest with a T valve, allowing the pump to be feeded either from the chest or directly from the fresh water tank.

 

[MapisM]

something I would have expected on a Canados (fresh water in stead of salt water anchor shower)

Bart, the major drawback of a chain wash circuit working ONLY with fresh water is the huge consumption of course.
Just think of spending one week along the Croatian coast, possibly mooring in two or three different places every day.
Unless you have a w/maker, rather sooner than later you will have clean chain(s) but no more water for a shower...

 

[jfm]

Wouldn't it just pay to have a water maker onboard? I guess the Sqn.78 has one?

Yes, sq78 has 150litres/hour of w/maker and it gets used plenty.

 

[jfm]

For the "last anchor retrieval" case, it would be sufficient to connect the pump hose to the chest with a T valve, allowing the pump to be feeded either from the chest or directly from the fresh water tank.

Agreed. So long as the T valve is electric with a switch on the flybridge, so you can select raw or fresh water on that last evening without having to go down to the e/room. [/Lazy git]

 

[vas]

thanks to all contributions I'm up to plumbing layout, v.5 (or six, not sure...)

A. gray water underfloor tank under the corridor to the cabins that hopefully works with no pumping about for the two showers + aircon condensation + possibly small front bilge pumps (it's a wooden hull, so seems that one frontal pump is not an option with the frame and keel as it stands). No treatment, just dumps overboard when full with a pump on a float switch.
B. two washbasins dump straight to sea from separate holes [thanks for the pointer jfm]
C. two heads to a holding tank aft flushed using freshwater from a pressurised system through a secondary tank that is fed from the primary water circuit with a one-way valve in between to avoid contamination
D. kitchen sink fitted with food waste disposer and straight out to sea using existing routing [check possibility to convert the motor on these to 24V]
E. keep the 2X250lt inox fresh water tanks aft and at a later stage (and when I wont be as skint as I'll be by easter when project is going to be ready) add a watermaker

[ott]
F. fit 3way electrovalves on engines seacocks and run engines on freshwater for a few mins when about to store (MapisM TM) [expensive ev needed for engines though (what, 1 1/4 inch?) ]
when I get on with all the repairs and install a BMS system, will use it to turn the valves back to sea possition once engines are off to avoid starting engines and running off through freshwater and seizing engines when half a ton of water is used after 20mins or so... Ideally should have ev (on-off) on the seacocks, followed by the 3way ev (sea-fresh)

[and now getting slightly silly...]
G. seacock in the bow with pump on timer to spray the new teak deck to the bow with sea water to keep it cool and nice during the summer [need to integrate a dozen or so irrigation nozzles with 180deg spraying pattern...] Same seacock, different pump will clean chain and a third pickup will provide cool water to the aircon.

thanks for all ideas, will spend whole day tomorrow in Athens on the boat, checking things, servicing and understanding how subassemblies work, replacing burnt bulbs, checking electrical contacts, checking the autopilot and upper helm and generally preparing for the 190nm delivery trip that should be done during the next 10days.

cheers

V.