Author Topic: A32 - macerator or gravity holding tank dumping?  (Read 544 times)

Holdech

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A32 - macerator or gravity holding tank dumping?
« on: December 22, 2019, 11:53:37 AM »
Prepping our A32 for its trip south.

Curious what others have done for offshore dumping of their holding tank?
It appears our tank is high enough for gravity to do the trick. Or I could add a macerator between the tank and thru-hull?
The third option is an electric head that macerates what goes into the tank.

Curious what others have done?

Chris
Chris, Teliki, A32

Bruce

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Re: A32 - macerator or gravity holding tank dumping?
« Reply #1 on: December 24, 2019, 10:13:13 AM »
Sorry, no relevant experience, but it seems to me that the liquid is the greatest tank filler that needs to be dealt with.  Bruce
Bruce,  OKAGA, A32

Jeff.

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Re: A32 - macerator or gravity holding tank dumping?
« Reply #2 on: January 08, 2020, 10:22:03 AM »
Hey Chris,
We installed a seacock and macerator plumbed into a Y valve in the pump out hose.
This setup worked great as we could pump out normally when in inland waters and switch to pump overboard while out in deep water.with the exception of composting head this was the default setup we encountered. And yes people often talk about their waste setup.. for some reason..

I have seen gravity dump on charter boats before it appeared to work well, the tank was quite high in the hull however.

Jeff
Aloha 32 Elixir V

Bruce

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Re: A32 - macerator or gravity holding tank dumping?
« Reply #3 on: January 09, 2020, 10:47:04 AM »
Speaking from personal experience,  if you still have the original aluminum holding tank , check for soft or corroded pipe in the outflow line to which the hose attaches. I developed leaking there while on cruise in the North Channel and after a quick return south to my marina, we found that entire pipe area to be disintegrating.  This would be catastrophic while off shore as you plan.   Bruce
Bruce,  OKAGA, A32

Holdech

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Re: A32 - macerator or gravity holding tank dumping?
« Reply #4 on: January 09, 2020, 11:06:26 AM »
Ours came with a rotted out holding tank "free of charge" lol. The entire bottom and pipe was paper-thin and riddled with holes.

We replaced it with a 30-gallon rectangular plastic tank (see pic).

I think "catastrophic" would be an understatement for a holding tank failure.

Chris
Chris, Teliki, A32

Bill Hutton

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Re: A32 - macerator or gravity holding tank dumping?
« Reply #5 on: January 09, 2020, 01:09:15 PM »
Hey Jeff,


I'm interested in the position of your Y-valve with respect to the height above the waterline and whether there is a vented loop (I could picture a siphon starting if the tank is below the waterline like mine).


What I'd like to ask is how strong is the motor on a macerator? How high can it pump above the level of the tank?


When in Bahamas a friend of mine used a big manual bilge pump attached to a 2x4. The pump had a long hose that he dropped into the water and a short hose that he attached to the waste deck fitting.  In a harbour he'd fill up his holding tank, and then when offshore he'd bring his pump on deck and then empty the tank.  In a pinch, do you think a macerator would be able to replace the bilge pump on the deck with a long hose?.


As you can guess my boat is in the water and we hope to head to the Bahamas in a few weeks..... I'll create a proper thru-hull next fall, but I'm looking for a cheap and cheerful solution for the next couple of months.


Regards, Bill
Bill Hutton

Holdech

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Re: A32 - macerator or gravity holding tank dumping?
« Reply #6 on: January 09, 2020, 06:20:07 PM »
Hey Bill.

Thought I'd mention the setup on my friends Beneteau 37 that we sailed from Bermuda to St Martin last fall.
The macerator (Jabsco) was initially located about a foot above the holding tank. If the tank was completely full, it would prime in about 20 seconds.
If the tank was half full it would run until the impellor heated up which slowed the motor and tripped it's thermal switch. A week of this killed the macerator.
Thinking it was a defective macerator we repaced it but it died the same death.
Lowering the macerator to tank top level solved the problem. So I guess it would reliably pull "stuff" from about 15 inches below it. Two feet? nope.

We also had to rewire the macerator with proper gauge wire for the current it drew. The installer used one-way distance instead of the total trip in his calculations and undersized the wire.

In November we sailed a 47 foot cat from Panama to Puerto Rico. It had a gravity dump arrangement that seemed to work well, hence my initial question. He didn't allow toilet paper to be flushed which to me (us) is pretty gross.

Hope this helps,

Chris

PS - if you ever need crew....
Chris, Teliki, A32

Jeff.

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Re: A32 - macerator or gravity holding tank dumping?
« Reply #7 on: January 14, 2020, 08:25:07 PM »
Bill,

I too first thought of the side deck manual pump. A boat in my club used one in the Bahamas. Seemed to work fine for them.
I thought of using an electric pump in the same way but im guessing the priming height was to great for those pumps and that's why I didint try it.
Currently my tank, y-valve, pump and through hull are all below the waterline.
When you pump out, even at six knots, you can really smell it. I would guess a manual method would be.. less elegant.

I don't have a siphon break, I only open the seacock to pump out and then I close it right away.

Hope those helps your decision.
There really are no pump outs over there.

Fair winds
Jeff
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Bill Hutton

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Re: A32 - macerator or gravity holding tank dumping?
« Reply #8 on: January 23, 2020, 09:10:15 PM »
Great responses guys.  Thanks very much.
Bill Hutton