Holding Tanks

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evmars1

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Hi experts, me again!

We're wintering in SE Spain, with the intention of heading east in April. The boat is a 9 mtr Catalac.
I'm in the process of replacing the stbd water tank, so now is the time to think about fitting a waste holding tank.
Do I fit a holding tank, vent, changeover valve etc (costly and not easy) or can I legally get away with a porta potty?

Your thoughts please,

t.v.m

Da /forums/images/graemlins/blush.gifvid
 
Before you do, ask Jimi about holding tanks.
 
Look at the simple, 'straight through' variety. Rod Heikell recommends these in his Med cruising books and almanacs. Very simply speaking, you insert a tank with vent into the existing discharge pipework. When at anchor, close the outlet seacock. When sailing again, open the seacock and either let gravity empty it or use the toilet to pump it out. Plastimo and Vetus are now doing a variety of sizes of this type of tank. Saves fitting a diverter valve and extra skin fittings, very valuable savings on a smaller boat.

I have not seen any facilities for emptying a chemical toilet in Spanish or French Med marinas. Even if you empty it down a toilet it's not normal for there to be any fresh water tap that you can get the tank underneath for rinsing. Can be done, of course, but lots of hassle and possible embarrassment!
 
That's a good tip. Simple is always better. I have a conventional holding tank
but have never finished the installation since I want no more pumps or skin fittings.
 
When planning on the fit of a holding tank to my 9m Catalac. I finally decided on three options:

saddle tank on existing heads (used to be an option for Par Brydon loo)
Rectangular tank in the heads compartment between the loo and the aft bulkhead underneath the moulded sink unit (mk2 catalac)
V tank forward end of stbd engine compartment.

I had decided on a V tank at forward end of the engine compartment (I have an outboard so lots of space.

Never got round to the fit as plans changed.
 
I have the 'saddle tank' on an RM69. Only fitted due to absence of space to fit one anywhere else, apart from a custom one behind the loo that would have presented its own difficulties. I cannot say that ours is ideal. It's on the small side, not very easy to flush out and difficult to measure how much is in it. We use it as little as possible.

Interesting to note that when solid waste is pumped out close to shore in the Med, the whole lot is eaten by fish within seconds. So is the absence of fish in the North Sea caused by pollution control?
 
As there are no pump-out facilities, that I know of, in the Western Med and, I'm told, none in the Eastern Med fitting a holding tank (unless you're an anal obsessive) is redundant.

Your waste, as Vyv Cox, so succinctly explains is soon converted into piscine biomass.

Your PortaPotti is, however, definitely ecologically unfriendly as most additives used in them contain formaldehyde which is toxic to all life (marine or otherwise).

A case can be made for fitting a buffer tank (apparently in the jargon there is a difference from a holding tank) to avoid pumping your waste out in places where there are a lot of swimmers - that too founders in the Med where anchorage and swimming areas are rigourously demarcated.

I've got a saddle tank on an RM69 - the one time I tried to use the original, it was discovered that the down-pipe had come away and I had to disconnect it and manually empty it over the side in the Bonifacio Straits - an unpleasant and dangerous business.

I would strongly recommend ditching the PortaPotti and fitting a conventional marine toilet with a saddle tank for show (only).

PS I discovered about the difference between holding and buffer tanks the hard way when I had to the get the replacement (1st time WRONG) for the RM69 from Raske & van der Meyde. Tho' both were free the transport costs were about £25.
PPS Someone at Aberystwyth is apparently doing a PhD on the theory propounded by Vyv, ie organic waste being good for fish stocks. Certainly the catches in the Med are, contrary to "expert" theory, rising - tho' that may have more to do with the "inefficient" fishing methods being used.
 
Can't speak for the efficiency or otherwise of the fishing but I have seen the density of it on several occasions. At Palamos and Roses last season we were arriving just after sunrise as the fleets were leaving. Boats poured out for best part of 30 minutes and scattered in all directions. There never seems to be a shortage of good fish for sale along this coast so they are presumably all getting a reasonable living from it. Puts our fleets to shame, what remains of them.
 
Having cruised in the Med the last 4-5 years I'm still surprised by the attitude of cosailors considering themselves welldoers and fish feeders. Operating in tidal waters its understandable, but in the Med no tide clean up the anchorages every 6 hours. Or are those welldoers not enjoying a morning swim when most fishfeeding is done? Or swim at all? With a holding tank and a 3 way vent it should not bee too inconvenient to keep our stuff to deposit 3 miles out.

PS.
Look out for a holding tank of stainless steel. They last only a few years.
 
Mediterranean Fishing

Siracusa market is the one to go to - about 40 fish-stalls, all with a remarkable variety of fresh fish, about 80% of it from the Med.

Sole @ €8.50/kg, admittedly not our Dover sole, but equally good and about twice the size of the dwarf fish you may occasionally see in our near-extinct fishmongers.

Malta, by comparison, is a gastronomic disaster area.
 
Re Holding tanks

Thanks for the feedback so far.
I am told that holding tanks are compulsory in Greek and Turkish waters. Has anybody had their boat inspected, if so, how thorough was it?

t.v.m.

David
 
You confirm the point that I am making. "Everybody knows" that sewage kills fish and deposits itself on beaches. This is patently not true. I have been told that very little sewage treatment is carried out by the Spanish on the Med coast. It is common for raw sewage to be discharged into the sea all along the Costas Brava and Dorada and in the Balearics. But is there sewage on the beaches? No. Are there lots of fish about? Yes.

In fact I am a very keen swimmer and snorkeller and make a point of watching the fish feeding on a wide variety of foods. At a distance of a couple of metres from the boat there is very little chance of being contaminated - all food is eaten long before it can reach me.
 
Re: Re Holding tanks

In nearly ten years in Greek and Croatian waters I have never been asked for
a skippers licence or to see a holding tank. I have one but in practice officials
have no desire to leave their offices and board your boat.
I suspect the same is true in Turkey, BUT the penalties for harbour discharge
are draconian and only apply to foreigners!!
 
Re: Re Holding tanks

May I just add a couple of things?

1) in Italy local "Capitaneria di Porto" decide and issue orders preventing private craft sewage discharge witin the harbour(s) and within the SIX MILES distance from coastline. No national wide provision.

2) As I graduated in hydraulic engineering discussing a thesis on "Sewage disposal at sea", i can assure the Sea has a self-sanitation ability, greatly increased by dilution: fact is, pollution needs a time span to be naturally overcome (say 1 hour).

Cheers,
Gianenrico
 
Spanish law now requires all spanish registered 'pleasure craft' over a certain length (I think 7 mts but don't quote me) to have holding tanks of a size adequate for the normal number of people who use the boat. As you can imagine tghis is a very subjective figure. Doubtless this will soon be compulsory for all craft. The law is already in place to prevent you dumping waste overboard within a considerable distance from shore so as long as you don't need the loo there's no problem!!!

As the same law also requires marinas/ports to provide pump-out facilities and as someone has said there literally are none on the spanish Med coast you can see that as normal the continentals are treating the law as it suits.

However an upset Guardia Civil officer probably wouldn't accept this as a valid argument and doubtless it will cause trouble if you don't have one.

We fitted a 50Lt in-line gravity tank to avoid diverter valves etc. and this has worked very well indeen. Big enough for two of us for two to three days whilst in the nice anchorage and then we dump once out to sea on passage. I have details, diagrams, costs, suppliers etc from an owners association article. Please feel free to PM me if you want any more details.

Chas Roberts
 
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