toilets

The watery and smelly sides of life.
44c
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Location: Hervey Bay, Qld

toilets

Post by 44c » Mon Aug 11, 2008 9:47 pm

mahnamahna wrote:Just one more thought. All the airlines in the world use vacuum toilets, there must be a reason they prefer them over pumps and macerators.


Yes there is. Water is heavy, vacuum weighs nothing. In boats we have an unlimited supply of seawater right under us. Aircraft have to burn fuel to carry water. At high altitude aircraft are surrounded by near vacuum, just as our boats are surrounded by water. In both cases it seems logical to use what's freely available, just outside the hull, to flush the toilet.



Do Lavac guarantee that tampons won't block their toilets? They certainly can block block the usual 1 3/4" line when they are saturated. Do they specify bigger plumbing?



If you don't have either a sign or verbally ask people not to flush tampons, I would say you can look forward to a lot of extremely unpleasant tasks.

mahnamahna
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Location: Gosford NSW

toilets

Post by mahnamahna » Mon Aug 11, 2008 10:23 pm

Do airlines really expel waste instantly overboard? I thought that was an urban myth. Its a wonder we dont hear more of matter falling from the sky. Or perhaps I misunderstand how airlines take advantage of the vacuum up there. Nonetheless I take your point. And I also take your point on letting female guests know the etiquette on board, I am kinda hoping my wife will take that one on. Catholic guilt really has messed with me in delicate areas like that!! We visited friends on board their cat in Auckland and they had no compunction telling Jo not to flush even toilet paper in their toilet. I don't know what system they had on board, but it was a cheap Sth African production boat so I dont think it was a vacuum. It may also have been because they were sneakily expelling overboard in a non discharge environment! I dont know. Just one other percieved advantage that I forgot to mention about using fresh water, it is just one less through hull to possibly fail. Call me paranoid but the less chance of outside getting in is fine by me. I want a deck hose to wash my anchor chain in muddy anchorages but am not thrilled about having a salt water intake near the front. I will have one at the stern but the take in for that can be in the outboard well that is flooded at the through hull anyway, not ideal as so near the motors I might get oily water and it means I will have to run the hose through the sole to the front, not a big issue and the likely path I will take on this, but that is a another thread topic I guess. One thing is for sure, I would rather be chatting about boats than working!

mahnamahna
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toilets

Post by mahnamahna » Tue Aug 12, 2008 2:46 am

After some further research I found this http://www.marine-surveyor.com/newsletters/9910.html It is an archive on a marine surveyor sight all about holding tanks and heads. The interesting stuff is about halfway down and onwards all about how most builders build breathers to be as far away from humans (ie up a mast etc) and in effect this lack of real air movement due to the distance air ingress has to travel is the actual cause of bad smells, aerobic v anaerobic bacteria. It seems counter intuitive to have airflow through the tank, but I am no scientist.

northerncat
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toilets

Post by northerncat » Tue Aug 12, 2008 5:39 am

mahnamahna wrote: I would rather be chatting about boats than working!
as would we all sadly when we do this it looks at us forlornly as if we have sold out

sean

mahnamahna
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toilets

Post by mahnamahna » Tue Aug 12, 2008 6:06 am

Oh no Sean, I didnt mean working on the boat I meant selling stuff, keying orders, boring work work!

Smooth Cruiser
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toilets

Post by Smooth Cruiser » Tue Aug 12, 2008 4:54 pm

With regards macerators etc - for anyone interested, below is section 38J of the Queensland Marine Pollution Regulations. I am perhaps one of the few people who actually read the act and regulations cover to cover. Everyone else that I have talked to has relied on heresay printed in questionable publications. I was headed full tilt down the path of fitting a holding tank, because of all of the sensationalist stories I was reading about $75,000 fines for even someone canoeing around who took a leak off the boat.



Then I paused and read the regs and found that I didn't require a holding tank at all. I have had this confirmed in writing from the Manager of the Marine Pollution Unit of Maritime Safety Queensland. (And I have his letter printed out and laminated on board ready to show any overzealous official). A macerating device is required for any vessel in survey or any commercial ship. IT DOES NOT APPLY TO US!!.



Section 38J Sewage discharges in coastal waters, other than nil
discharge waters

(1) This section applies if a ship is operating in coastal waters,
other than the nil discharge waters for sections 47 to 49 of the
Act.42
(2) The master of the ship must not discharge, or allow any one
else on the ship to discharge, sewage from a toilet fixed
permanently on board the ship into the waters unless—
(a) the sewage first passes through a macerator; and
(b) the macerator effectively reduces, for example by
grinding, shredding or pulping, solid wastes in the
sewage into, at least, a fine slurry.
Maximum penalty—350 penalty units.

Hangtime
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toilets

Post by Hangtime » Tue Aug 12, 2008 5:57 pm

Smooth cruiser do you have a direct path from toilet to through hull fitting ?

I have tried QLD transport and the nsw Maritime over the phone and got vague and unclear replies

Smooth Cruiser
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toilets

Post by Smooth Cruiser » Tue Aug 12, 2008 10:12 pm

Hangtime wrote:Smooth cruiser do you have a direct path from toilet to through hull fitting ?
I have tried QLD transport and the nsw Maritime over the phone and got vague and unclear replies


Yes I do. And this is fine for everywhere except nil discharge areas. (Marinas, harbours or canal estates and some sections of Moreton Bay and Harvey Bay).



I would suggest emailing them rather than phoning, on the phone you don't know who you are talking to and they can be deliberately vague. If they put a response to you in writing then they can no longer be vague. I got a very polite, very comprehensive reply within a day or two of my email, which was only sent to the general contact address on the web site.

puremajek
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Post by puremajek » Wed Aug 13, 2008 7:35 am

Yes there is. Water is heavy, vacuum weighs nothing. In boats we have an unlimited supply of seawater right under us. Aircraft have to burn fuel to carry water. At high altitude aircraft are surrounded by near vacuum, just as our boats are surrounded by water
Nearly right here 44C, most Boeing aircraft use up to 1 liter of water and vacuum per flush. The vacuum is insufficient below 16000' and is provided by an electrically driven 28V vacuum pump, specific to the lavs only. Above 16000', a barometric pressure switch disengages the pump and differential pressure is used.



However, water is used on each flush and the water tank (same water that goes to the taps by the way), is replenished on each turnaround (about 250lt for this purpose on 737)...normally.



Talking about smell too, on aircraft, when the lav system is out of water, thats when you start getting the smell.
Last edited by puremajek on Wed Aug 13, 2008 8:12 am, edited 1 time in total.
James
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http://www.diycatamaran.com
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puremajek
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Post by puremajek » Wed Aug 13, 2008 8:11 am

Alasdair



I have been unable to locate data for operations outside ‘nil-discharge waters’ and can only assume that they are yet to dabble in that area. I received a letter in May from them, referring me to the Amended regulations http://www.legislation.qld.gov.au/LEGIS ... pMPA95.pdf.

> Here in Part 7 ( page 32/3), they talk only about ‘nil-discharge waters’ again.

> Section 49 (1) pg 36, starts to get close.

> I can only find section 51 (pg 37) that pertains to us.
51 Shipboard sewage management plan
(1) This section applies to a ship declared under a regulation for
this section.
(2) If a ship does not have on board a shipboard sewage
management plan, the ship’s owner and master each commit
an offence.
Maximum penalty—850 penalty units.
(3) If a ship has on board a shipboard sewage management plan
but is not fitted with any equipment that may be required to
implement the plan, the ship’s owner and master each commit
an offence.
Maximum penalty—850 penalty units.
(4) A regulation may prescribe minimum requirements for a
shipboard sewage management plan.
The way I read the document is that if I remain clear of all ‘nil-discharge waters’, a holding tank and/or macerator are not required.



However, if I choose to enter ‘nil-discharge waters’, I need both purely because I have a fixed toilet only.
Last edited by puremajek on Wed Aug 13, 2008 6:41 pm, edited 1 time in total.
James
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