2007 Phantom 40 Black Tank Problem

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2007 Phantom 40 Black Tank Problem

Postby Ged Hale » Wed Mar 01, 2017 7:18 pm

Hi,
this is my first post as a new yacht owner and I would like to congratulate Fairline on the superb build quality . Almost like New at 400 hrs.
After spending our first week on board we were perturbed to find the Black tank gauge on full as it had been emptied at sea a few weeks earlier and not used since. Suspecting water ingress it was emptied ( assuming gauge working correctly) depressing the pump for approx 2 minutes so there was a zero reading .
within hours with the main water pump turned off at the helm and water drained from the taps to remove any residual pressure, the gauge read as full again.
The process was repeated several times with the same result.
Has anyone had a similar experience. Can sea water find its way into the tank in any way? Tap water goes outside and the showers have not yet been used.
Many thanks for your assistance in advance. :)
Ged Hale " MARABU" Portals Nous, Mallorca
Ged Hale
 
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Re: 2007 Phantom 40 Black Tank Problem

Postby frandroid » Thu Mar 09, 2017 12:01 pm

Hi Ted
Congrats on getting a great boat! Mine is about the same age and we've had some 10 years of pleasure cruising the western Med including several trips to the Balearics.

I'm not on board at the moment, and I haven't experienced your particular problem, but I'll try to offer a few pointers. I think there are about 4 inlet/outlet pipes going into the black water tank (apart from a vent that should out above the water line anyway).

Two pipes come from each of the heads (via 2-way divert valves which offer a choice of head outlets going direct to sea or into the black tank). Even if these are set to the tank position, you've shut off the fresh water, so there's no possibility of water from a leaking head going to the tank.

Another connection is an outlet that goes to the port deck, for dock side pump out of black waste. As this is well above the waterline there's no possibility of sea water leaking back.

The next outlet from the tank goes to the black waste pump, which then goes via a shut off valve to an adjacent through hull fitting. When open, this allows you to pump out to sea. As this is all below the waterline I'm wondering if you are getting sea water feeding back. Be aware that this valve should normally be closed, and only opened when you choose to pump out the waste to sea (it's illegal in most countries to do this in port anyway, and should be done only 3 or 4 miles out to sea).

You probably already know where the tank can be found, under the hallway hatch outside the guest cabin door.

Let me know if you need any more info.

Francis

Cara Maria
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Boat: Phantom 40

Re: 2007 Phantom 40 Black Tank Problem

Postby Ged Hale » Sat Mar 11, 2017 9:20 am

Francis,
Thank you for your very helpful post.
I have been investigating the problem myself during a 2 day visit and took the top off to find exactly what
you describe.
I didn't dip my finger in to check but I'm pretty sure it's sea water.
I didn't find the waste outlet sea cock but will try next time, I am sure that's the problem as can't see any way it could happen if it is sea water.
I have not had the benefit of a " handover" from the FAIRLINE brokers thus far but will insist next time out as I
am a 1st time owner with a smattering of technical interest and much enthusiasm.
One or two sea cocks appear stuck through lack of use , not mentioned on the survey so fun to be had there too. Can freeing be done in the water?
Thanks for your help ,really appreciated.
Best wishes,
Ged
Ged Hale
 
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Re: 2007 Phantom 40 Black Tank Problem

Postby frandroid » Sun Mar 12, 2017 3:01 pm

Ged (apologies for mispelling in previous post - that's auto correct for you)

Just to the portside of the black tank there should be three adjacent through-hull sea-cock/ valve fittings all in a line from front to back. The front and middle one have larger flexible pipes fitted for the owner and guest WCs direct outlets to sea (they come via diversion valves located each side of the hatch so you have to kind of look up inside the floor hatch to see them!).

The third one has a slightly smaller diameter hose that comes from the pump (located nearby) that pumps black water out to sea. If the valve handle in pointing up (in line with the pipe) then it's open, and it's very likely that water is dribbling back through the pump into the tank. I'm not sure whether the top of the black water tank is just above or just below the water line, but it must be a close thing!! Either way it's not good and potentially dangerous, especially when pitching at sea.

As a matter of course these three valves should be in the off (perpendicular) position until you need them open. When I'm discharging to sea I'll open the valve to pump out then close it immediately afterwards so it's sealed off.

Sticking valves/sea-cocks are a real problem if they are not exercised frequently, which i found to my cost when the aircon valve seized and i broke the handle trying to free it. It's not normally rust, but more usually salt which hardens in the ball joint inside, and it normally seizes in the closed position as the ball is exposed to the sea. Definitely more of a problem in the salty Med.

Hopefully you can free it in the water by gently but firmly rocking the handle backwards and forwards beginning with small movements to get it started. Once it starts you can hear the salt crystals being crushed as the handle turns!

Having learned the hard way, I now make sure that I exercise all valves several times a year, or usually at every visit.

Good luck!

Francis
frandroid
 
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Boat: Phantom 40

Re: 2007 Phantom 40 Black Tank Problem

Postby Ged Hale » Sat Mar 18, 2017 6:15 pm

Francis,
Thanks again, i found the waste cock without realising it was the one that needs closing to confirm that it is sea water ingress. I strongly suspect the cocks have not been exercised for ages so will proceed with caution.
I also think the tank is at or below the waterline otherwise the problem could not occur.
I will be making some measurements when I return very shortly.
I believe that there may be a way to dissolve the salt in the sea-cocks and wonder whether you have any thoughts on this?
It will be problematic where they are stuck open ,I suspect, without an expensive lift out!
Your help is much appreciated.
Thanks,
Ged
Ps have ordered a new anti siphon valve ( £ 25 ) as that must also be faulty , I assume just need to trace the pipe back to fit it , it should be above the water line or there will be trouble!
Ged Hale
 
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Re: 2007 Phantom 40 Black Tank Problem

Postby Ged Hale » Mon Mar 27, 2017 4:48 pm

Now the new anti siphon part has arrived , I can see that the only operational part is a small rubber duckbilled valve the size of your little finger nail!
If this part fixes the problem I will be very happy and will report the outcome at the weekend.
Ged
Ged Hale
 
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Re: 2007 Phantom 40 Black Tank Problem

Postby Ged Hale » Fri Aug 04, 2017 7:06 am

Francis
Closing the outlet sea cock solved the ingress of water immediately.
Cannot presently see where the one way valve is located , any ideas to access it?
Thanks for all help thus far.
Ged
Ged Hale
 
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