Gravity discharge holding tank

[NYSail]

Hello all,
So completed holding tank co version. Beneteau has such a tight under the sink area plus used an over complicated amount of hoses and thru hulls. So I removed the macerator pump and reconfigured to gravity fed holding tank. Now bottom of tank fitting (original deck pump out) goes directly to a thru-hull fitting about two feet away. Then I connected the deck pumpout to the old macerator fitting that has a pvc pipe running to bottom of tank. I oriented the pvc pipe directly above the bottom of the tank gravity fitting so if there is ever a blockage I can put a hose into the deck pump out port and flush it out. Also with this upgrade I was able to eliminate 1 thruhull fitting and get some additional under sink storage space (have to relocate shower pump next). 1 project down......

Greg

 

[StargazerP303]

That looks great!! Love how clean it looks too!

 

[Gunni]

I have contemplated that method and reached the conclusion that; 1) the droptube does not completely evacuate the tank, leaving solids in the tank bottom, and 2) Solids will fill the tank-bottom gravity feed overboard discharge and clog it. I would be interested how this works out for you.

 

[NYSail]

My tube fits right into the now gravity drain just enough to get over 99% of the “crap” out if not more. Also as I said it is positioned right over the bottom fitting so it ever gets plugged I can flush with hose from deck and clear. I have electric macerating toilets so holding tank is liquid..... and hose from tank to thru hull is less than 2 feet and nicely downhill. I wish I could post a video (to large)...... I am happy with results and will do aft tank as well!

Greg

 

[Bob S]

Looks great, I will be doing my forward head soon. I have not used it yet but Peggie's recommended Norflex should help with any sludge buildup.

 

[Peggie Hall HeadMistress]

No-Flex does digest sludge, but it doesn't relieve you of the need to thoroughly flush out the tank and any overboard discharge plumbing a couple of times a season, and especially in prepping for winter or other extended layup.
--Peggie

 

[Gunni]

Good reason to go out a few miles and into the blue.

 

[NYSail]

That is the joy of this set up.... the pick up for deck discharge sits in the small sump for the bottom discharge. If I put hose in deck fitting water will go directly into bottom discharge hose giving a good flush.

Greg

 

[NYSail]

When putting on the hard I will go below the fitting with a bucket and have wife open, then I’ll bring last dribbles into the bathroom and flush. Hose is less than 2 feet so not much will be in there......

Greg

 

[TimFromLI]

How do you pump out since you can't discharge into the Long Island Sound?

 

[NYSail]

I didn’t eliminate deck pump out. As I said I only removed the macerator and all hoses and converted to gravity discharge. All tanks (at least that I have seen) have both options. Look at the pictures I posted and you can see what I did

Greg

 

[TimFromLI]

My boat can't discharge direct from the tank overboard, neither could my last boat. I never had a need to since it is illegal to dump raw sewage into Port Jeff Harbor and Mount Sinai Harbor or the Sound.

 

[Peggie Hall HeadMistress]

That is the joy of this set up.... the pick up for deck discharge sits in the small sump for the bottom discharge. If I put hose in deck fitting water will go directly into bottom discharge hose giving a good flush. Greg

But that hose is the only thing that will get rinsed out unless you close the seacock and put enough water into the tank to cover the bottom to a depth of about 4" twice. 'Cuz you'll be using the tank with a closed thru-hull when you're inside the "3 mile limit"...and while No-Flex will prevent a buildup, "dirt" and bits of TP can stick to the bottom of the tank if it's not flushed out occasionally. Not that hard to do just 2-3x/season and a part of prep to haul out for the winter.
--Peggie

 

[NYSail]

But that hose is the only thing that will get rinsed out unless you close the seacock and put enough water into the tank to cover the bottom to a depth of about 4" twice. 'Cuz you'll be using the tank with a closed thru-hull when you're inside the "3 mile limit"...and while No-Flex will prevent a buildup, "dirt" and bits of TP can stick to the bottom of the tank if it's not flushed out occasionally. Not that hard to do just 2-3x/season and a part of prep to haul out for the winter.
--Peggie

Yes..... sounds like excellent stuff.and have it on my list. when I go to pump out dock here in my harbor I always do a full pump out then fill the tank half way with fresh water and he pumps me again...... try and keep it clean as possible!

Thanks!

Greg

 

[NYSail]

My boat can't discharge direct from the tank overboard, neither could my last boat. I never had a need to since it is illegal to dump raw sewage into Port Jeff Harbor and Mount Sinai Harbor or the Sound.

Without a doubt it’s illegal and I never do. I get pumped out every weekend even though I have 50 gallon capacity over two tanks...... why not it’s free (other than tip) and takes a couple of minutes.. However when I go off shore there is no problem as long as you are outside of the discharge zone. I have discharged overboard only a few times. But every boat I ever had and actually every one of my friends boats that I have been on was designed from the factory with this feature. Figure the gravity is the way to go and eliminate the pump.

 

[All U Get]

Since I helped a friend with a clogged tank in the Exuma’s, I would not be comfortable removing the macerator for the sake of a gravity dump. Besides reducing the size of any solids for quicker biodegrading, it reduces the time it takes to discharge by forcing effluent out. Then the slight change in operating sound lets you know it’s empty. With just a gravity drain, how would you know?

 

[NYSail]

I can hear the level of my tanks when I flush.... Eventually could put a tank monitor on or just open the inspection port....access in about 2 minutes. see pictures above. Also my electric toilets have macerators built in so tank is essentially liquid. Macerators break also.... I was in the Atlantic last summer east of Block Island... could not get a pump out before I left due to weather and fact that I would have had to wait a couple of hours for the boat to arrive, so when I was about 7 miles east of block I went to empty tank and nothing... macerator pump broke.

 

[All U Get]

A cruising friend has a hand pump to discharge his tank while off shore. Our boat has the electric heads to the holding tank and an electric diaphragm pump to do the overboard discharge. Both work well and can be done regardless of sea conditions. I’m just not a fan of relying on gravity, besides look how many mechanical engineers would be put out of work. (Peggy don’t read this)

BTW why are you awake so early?

 

[NYSail]

Part of the reason for this also was the fact that Beneteau built the 423 maximizing living space and killed below sink storage in the bathrooms..... So by doing this and removing all hoses and pump I opened up an entire world of storage possibilities!!

Ha....... so early?? A self employed guy that has to get so quiet work time done (morning guy). Problem is I have two monitors on my desk (home office), one with work and one with sailing content..... I do not stray to far from my pleasures!!!!!

Greg