Holding tank discharge pump question

  • Thread starter Thread starter Deleted User YDKXO
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Ah, yes now I remeber, Prin build it into the panel. It is Sealand stuff behind the scenes, Princess just (nicely) rip the Sealand stuff apart and build into the panel. You can still do what I have done though, becuase there isn't really much integration twixt the Prin stuff and the new stuff you'd be adding. In fact the only integration is to interupt the 24dc to the pump with the relay that I mentioned, which is controlled by the seacock open light. That's easy wiring, obviously. Beyond that, you dont disturb the Prin system.

Oh, also, you need to fit the seaccok open/shut switch but it is a carling so if you have a spare slot on the dash or somewhere put it there and buy a rocker to match your dash, then it'll look OEM

If I were you I'd fit the elec seaccok right above the manual one. You can't use the existing wire to your microswitch becuase you need 5 cores twixt elec seacock and its carling switch on the dash. So abandon the existing microswitch wire as that seacock will be open always. Or better still put the microswitch in series with the other seacock open sense wire, so that the pump only runs if BOTH seacocks are open

The elec seacocks are in the vetus catalogue. You'll almost certainly need the 1.5inch 38mm size. About £400. Other suppliers do smaller sizes, but only Vetus afaik do the 1.5inch-ers. You'll need 2 big stilsons to remove the hosetail off your current seacock and fit a nipple to connect it to the new elect seacock. A pair of big stilsons is essential gear for p67 anyway, to deal with seacock issues, I'd suggest. As you say, job for winter. Well worth doing though - I did it for same reason as you mention - I didn't want to lift floor hatches and muck about in the bilge, underway, just to open and shut a blimmin seacock!

Oh, incidentally, the new Aquafax online catalogue and stock list is much improved - they do oddball things like 5 core wire (I used 7 core trailer wire!)
 
Thanks for that

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A pair of big stilsons is essential gear for p67 anyway

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Funny - I had a problem with the engine seacocks sticking last week - both of them -

a pair of stilsons was the eventual answer /forums/images/graemlins/smile.gif

- no damage to the nuts so I've now invested in a big socket set and a long bar.

I've said before that I have to close the seacocks when we lift the boat so that the seawater system doesnt drain and beed repriming.
 
Silly question time, jfm but why do you bother with an auto electric seacock on the holding tank system? Is there a risk of sea water backing up into the tank? Or are all your seacocks auto electric?
 
jfm,

As you're clearly so knowledgeable about black water systems ("headmaster" perhaps), can you give me some advice on how to fix holding tank sensor lights. Mine simply aren't working, except one of the 'full' ones which is permanently on.

I suspect they simply need cleaning but I'm a bit crap ('scuse the pun) at plumbing so worried about ending up to my ankles in poo (I had an 'experience' on another boat, but that's another story).

TIA.
 
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Silly question time, jfm but why do you bother with an auto electric seacock on the holding tank system? Is there a risk of sea water backing up into the tank? Or are all your seacocks auto electric?

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Not a silly Q, but there is an answer! I have the holding tank discharge deliberately without a swan neck. The top of the holding tank is below waterline, so normal practice would be to take the discharge pipe and loop it up above the w/line. My h/tank is on centreline, so the swan neck would need to be taken to the edge of the boat and looped up behind a cabin wardrobe or something. That adds a full 5 metres of 1.5" pipe permanently lined in sh!t, and a source of smell. Whereas, if you go from tank to seacock directly, the pipe is only 1m long, but then you need a s/cock to stop the h/tank filling with sea

It's therefore quite important to keep the s/cock shut except when pumping, and so the 4th segment in my carling switch panel above is an ultra bright flashing blue LED (Roger would be proud) fed by the seacock open microswitch. It's v noticeable and should remind me if someone has accidentally opened the valve or something. Of course, a holding tank full of sea isn't a safety concern, just a nuisance. It stops filling with sea once the level in it has gone about a foot up the vent pipe, so the boat can't actually sink
 
No expert here but have got involved out of necessity (I have a new tecma macerator here in my bag to fit this weekend, urgh, I kid you not!)

If you have the 4-light sealand system it has 3 poles/probes sticking down into tthe tank with floats that slide up/down and trigger proximity switches. The sliding floats stick.

The floats slide up/down along 15mm dia metal tubes that are suspended vertically from the roof of the tank. You should have on the top of the tank a screw in fitting that holds all these tubes. To cure your prob:

1. check wiring is ok - the wires are quite fine
2. One at a time, loosen the black plastic collets that clamp the probe tubes. You'll see them at the top of the tank. Then slide the probe tube up and down quite vigourously, to loosen the stuck float. This works better if the tank is full, so you're sliding the flaot in fluid not air
3. If that doesn't work, you can unscrew the top of the tank fitting and take the assembly of 3 probes off (disconn the wires, obv) and clean it. Rubber gloves job, urgh
4. The wring logic is that when the full float is triggered the red light comes on and all the other lights go out. So it looks 99% certian that your "full" float is stuck. So in step 2 above concentrate on that one. It's the shortest probe, obviously, so there isn't much stroke to slide it up/down vigourously
5. If you have to do step 3 there is a throw money at it solution which is buy a new probe assembly (aquafax.co.uk or lots of places) and simply pull the old one out and fit the new. The benefit is you habve only limited personal contact with sh!t, but it's a rather daft extavagence (£100?), as steps 2/3 should cure!

Good luck, and if you get sprayed in sh!t we want a report here please. If there are guests dining on the boat remember to smear your face in shards of chocolate, etc, you know the drill :-).
 
Ah, OK. I do have a loop in my discharge pipe (which doesn't appear to be the source of any smell on my boat). Like your boat, my tank is low down in the bilges below the waterline but the discharge pipe exits the hull about 6" above the water line. The waste is funneled below the waterline by a sort of downpipe moulded onto the hull. I've taken the view that with this arrangement, seawater is unlikely to be drawn back into the holding tank and therefore I never close the seacock (although I move it occasionally)
 
OK
While we are on the subject of ?hit.
What is the best way to flush out the holding tank?
Indeed, is it necessary to flush it?

I have taken to going round all the toilets and flushing them several times whilst the pump is pumping out. Any other ideas?

I have always kept my discharge seacocks closed - just didnt like the idea of any seawater getting in and logically thinking, it would seem to me that if the boat is planing, there is a likely for water to surge over the swansneck into the tank - just didnt like the idea of an open seacock but no other reason. So would seawater in the tank be good for flushing?

Just dont know enough so I'll keep on flushing toilets whilst I'm emptying.
 
No I don't think seawater is good for flushing out toilets or holding tanks. AFAIK, it's the seawater which causes the 'bad eggs' smell in seawater flushed toilets when left for a few weeks. I guess seawater contains microbes and bacteria which can grow in stagnant conditions. Personally, I do what you do and flush the (fresh water) toilets several times and add some proprietary holding tank disinfectant before we leave the boat every time
 
Yep, i agree with Deleted User, keep seawater out as it must add more bugs that can makes smells. Headmistress advocates adding no chemicals but having a big vent, say 1.5inch, and the smell goes away on its own. Much as I respect her experience and views, I find her worng on this one - at least on a normal mobo the smell doesn't go, and btw I do have a 1.5inch vent fitted. Maybe it's a climate thing and it works ok in USA where she is based, and anyway i believe our european shiit is a richer higher quality connoiseur's shiit, unlike that cheap mass-produced american shiit :-)

So I do as you do. I flush the tank often with freshwater and a half bottle of tank cleaner chemical, and I find it eliminates smells

However I'de recommend you dont flush the tank by flushing the loos. The loos are all a bit crap engineering, flimsy cheap little motors and pressed components, you know what I mean. The extra running hours you inflict on them by flushing the tank via them seems like to cause an earlier failure imho. So I'd suggest emptying the tank at sea before you come back to your berth, then add some tank cleaner chemical thru the toilets, then 3/4 fill the tank with fresh water using the dock hosepipe thru the deck discharge. Much quicker, and no wear n tear on your WCs. Next day when you go to sea the motion of the boat will slosh the tank contents around, and you can then fully discharge the tank, and it'll be quite clean.

I also agree your theory that on a planing mobo the slamming can make seawater jump over the swan neck. I didn't mention that, but it's another reason I prefer my no-swan neck system with a positively shut sea cock

All imho
 
Ah, ok, haven't seen such a discharge arrnagement before. Yes, agreed, you wouldn't need to be so fussy about shutting the seacock with that system

Just imho, I wouldn't choose that set up if I had the choice. The shiit is at the surface of the water, yuk, and then might enter the spray around the aft 1/3rd of the boat as the boat is moving, and then get microscopically splattered onto the boat a bit - double yuk

I prefer the discharge down near the keel, amidships, then it will tend to be in the deeper part of the water and then gets nicely moulinexed by the propellers

Just imho - Ferretti might have better thinking...
 
Yup, the shite does exit at the surface but I always stop the boat at sea to make sure that the waste is actually discharging and to watch for air bubbles when it's empty, and therefore I don't get any skid marks on my hull. And it's surprisingly well moulinexed already without being mashed by the props. Oddly enough, it's always of major interest to any guests on board and seems to attract all sorts of wildlife too
 
Nope there are no pump out stations, and yes PV is literally dilute shite. The big s/yachts like carinthia 7 that dont move for literally a whole year must dump into the port, and I reckon lots of small boats do, or dont even have black tanks. I never do, and of course folks who own their own berths generally dont.

It's a shame really...
 
Yup, Palma is the same. It tends to collect in the north east corner where Pier 46 marina is which probably explains why it's easier to get berths there than any other marina in Palma. Don't worry, RCNP is not bad /forums/images/graemlins/smile.gif AFAIK
Theoretically, emptying holding tanks and toilets in ports is banned in Spain but, as you say, long term liveaboard boats which don't move have to do it. I've never heard of anyone being prosecuted for it though. Given the amount of development that's gone on in Spain in recent years and the huge influx of tourists in the summer, I would be surprised if sewage outfalls from the shore are a far greater environmental hazard than boats dumping their holding tanks into the harbour
 
We DO have a pump out station in Alcudia at the fuel berth. It's usually broken and when asked about it the marineros just shrug their shoulders.

Martyn
 
Thanks for the write-up. I think my sensors are horizontally mounted top and bottom so I'll have to dig a bit more (oops, there I go again). Will report results as long as they're not too embarrassing.
 
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then 3/4 fill the tank with fresh water using the dock hosepipe thru the deck discharge. Much quicker, and no wear n tear on your WCs.

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Aaargh - wouldn't want to be refilling my water tank after the hose has been stuffed down your discharge pipe (or do you stuff it up your discharge pipe?!)
 
I should have said, I click on a different hosepipe end, and my deck suck out has never been used for the transmission of shiit and never will be, so it's squeaky clean (except for airborne e-coli that have travelled 4m along the pipe, 5m on a p67, but those critters come out of the vent anyways...!

But yes, I agree with you that my suggestion above should NOT be followed if the deck suck out is actually used for the purpose intended!
 
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