400: Adding a holding tank

[Mixman1]

I have a 2011 Lagoon 400 owners version. The owners hull does not have a holding tank. Just discharges to the through hull. The other hull has one head and a holding tank. Has anyone added a holding tank? Any info would be appreciated. I am not confused about the plumbing process at all, just location of the tank, where to source a tank that will specifically fit, other details that might be of use.

Finally, I can obviously use the port hull when in a no discharge zone in the US. Do you think it is worth the trouble to install a holding tank at all?

[a64pilot]

With all the work required or install a three way valve and deck fitting etc, I wouldn’t do it, I’d have to want the use of that head pretty bad.

[Cheechako]

The simplest legal tank is just a vertical tank that gravity drains through a seacock. You can use that just like the tank is not there in a Discharge Zone. Or close and lock the seacock when in a No Discharge Zone.
I have no idea about where in your boat though.

[feebs]

L400 owners version normally has a holding tank fitted behind panel ( about chest height) on port side of owners shower stall. Bottom of tank can just be seen by removing inspection port below this panel or by looking up to your right with your head in cupboard below basin. - In this cupboard is where 2 inch valve is located to empty holding tank. There is also an overflow for holding tank, which discharges above waterline on port side of starboard hull about level with shower stall.

I hope it is installed & just been bypassed for whatever reason .....

[Mixman1]

Originally Posted by feebs

L400 owners version normally has a holding tank fitted behind panel ( about chest height) on port side of owners shower stall. Bottom of tank can just be seen by removing inspection port below this panel or by looking up to your right with your head in cupboard below basin. - In this cupboard is where 2 inch valve is located to empty holding tank. There is also an overflow for holding tank, which discharges above waterline on port side of starboard hull about level with shower stall.

I hope it is installed & just been bypassed for whatever reason .....

As odd as it seems, a holding tank in the owners hull was an OPTION in the Lagoon 400. And a standard item in the port hull. I will double check when I get to the boat today, but I am sure there is no holding tank there. There is no thru hull for pump out on that side. That's a pretty good indicator.

[peghall]

If you decide it's worth it to install a tank in the stbd hull, Ronco Plastics (no relation to the VegoMatic Ronco) is your best source. They make TOP quality thick-walled water and waste tanks for a very reasonable price and have more than 400 shapes and sizes, over 100 of which are non-rectangular, and they install fittings in the sizes and locations specified by the customer when they make the tank. There are retailers who sell Ronco tanks, but Ronco sells direct for a much lower price...and they're great to work with. Their current catalog is here Ronco Plastics marine Tanks but so many people find their previous catalog easier to search that they've left it available too Ronco Plastics old marine catalog



--Peggie

[cal40john]

I bought a tank from Ronco. They have a variety of different shaped tanks. In my case a V-bottom tank that tapers front to back to fit under the v-berth.
https://ronco-plastics.com/product/w...-holding-tank/

There's another company that also sells shaped tanks, but I can't recall its name.

[peghall]

Originally Posted by a64pilot

With all the work required or install a three way valve and deck fitting etc, I wouldn’t do it, I’d have to want the use of that head pretty bad.

He has a catamaran...I don't think he'll need all that plumbing to add a tank to the toilet in the other hull, and I suspect guests would find it very inconvenient to have to use the toilet in the owners head in the other hull in waters where they can't flush the guest toilet directly overboard


--Peggie

[meirriba]

We have a factory installed HT in an owner version of L400.
The location was described in a post above so I would not repeat.
But to add: If you install a HT in the shower stall, be aware that the new hose that will discharge the toilet into the HT goes a long distance from the toilet, under the sink into the stall, and the up to be connected at the top of the tank. So, ensure to make at least two inspection ports in the stall's wall at this location. This will allow inspection of this end if the hose, plus option of dismantling and reattaching the hose.
The standard inspection port as installed by Lagoon is useless as it shows only the middle of the HT.
The very long path if the discharging hose makes sure that it will be stuck after 3-4 years of use and then the suggested ports will be very useful.
You will also need a breething vent for the tank and if you want to be able to pump it out at a service station, you will need an access from the deck to the HT.

[chris mac]

We had the same issue on our (older) lagoon 42 tpi. Po had removed the holding tank and left it direct discharge. Then the most recent po removed the toilet and turned it into a pantry.
We installed a nature's head, cheaper and easier than installing a tank and all plumbing. And truthfully, I prefer it to the jabsco with holding tank that's in the owner's hull

[svsonora]

I know this is off topic, a taboo one at that, but I built my own composting seat thats basically a bucket, trash bag, and kitty litter in a bag and I have never looked back. no smell, no fuss, more storage room. The hardest part of that project was getting the holding tank out. the commercially available composting heads work even better.