The brown water blues - Can a sewage tank mess up my weight and balance?

[BigNickMontana]

Howdy everyone, I have a 66 Spencer 42 sloop.



I have been patiently awaiting my turn on the live-aboard list at my marina, and yesterday had some news dropped on me that in order to have anyone stay with me on the boat that I will have to get a bigger holding tank as my current tank is only 15 gallons, and they require 15 gallons per person.

I am going to be remodeling my head to contain a shower anyways, so the cabinets that are currently in the head are going to go away.



As you can see there is a sewage treatment unit that someone hacked into the cabinet face, it is supposed to be certified for discharge in a no discharge zone, to me it looks like a headache factory and thus I am going to remove it.

That leaves me with the cabinets that are hacked to death.

I am thinking of just cutting out the rest of the cabinet face, removing the drawers and building a custom sewage tank inside of the cabinet.

I ran some measurements over the weekend when I was down at the boat, and it would appear as though I can shoe horn a 40 gallon tank into that space if I build a custom tank.

The issue I am concerned with is that completely full this tank will weigh 344 lbs and my concern is that set on the outboard part of the hull like that it will cause the boat to heel hard over when sitting in port.

I was curious if anyone has any insight on this?

[Kelkara]

Originally Posted by BigNickMontana

The issue I am concerned with is that completely full this tank will weigh 344 lbs and my concern is that set on the outboard part of the hull like that it will cause the boat to heel hard over when sitting in port.

1) Sit two people on the rail of your boat and see how much it heels - That will be your answer.

2) The marina may require you to have a big tank, but they don't require you to fill it.

[Adelie]

It'll heel you over noticeably but not way over.

Preload the other side a bit and it will be a lot less noticeable.

Also find a way to up the tank to 45gal then you won't get gigged for having 2 guests.

Which direction is forward or aft? Hacked up cabinet top right in photo is foreward?

[markpierce]

Obviously, your boat was designed and built without a holding tank as such wasn't required then. Wonder what the owner was thinking that such a small tank (15 gallons) was adequate beyond meeting a new regulation. ... Anyway, a hundred pounds or less (30 versus 15 gallons) shouldn't have much effect on the boat's vertical alignment; nothing a little movement of internal contents couldn't correct if you're bothered. Also, removal of the sewage-treatment unit would save weight too.

[peghall]

The tank itself won't weigh that much, but water and waste weight 8.333 lbs/gal, so a full 30 gal tank can weigh upwards of 250 lbs.

Btw...Ronco Plastics (no relation to the VegoMatic Ronco) Ronco Plastics Marine Catalog is your best source for a tank. 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 several retailers who carry Ronco tanks--Plastic Mart and Raritan are two--but you can buy direct from Ronco for a lot less.

Peggie
"If you can't explain it to a six year old, you don't completely understand it yourself." --Albert Einstein
http://www.amazon.com/New-Get-Rid-Bo...dp/1892399784/

[leftbrainstuff]

We hav a 40 gallon holding tank port forward on our Liberty 458. It has no noticable impact on performance.

The racing purists will disagree but on a cruising boat / liveaboard it's certainly not a first order issue.

[ranger58sb]

Originally Posted by BigNickMontana

As you can see there is a sewage treatment unit that someone hacked into the cabinet face, it is supposed to be certified for discharge in a no discharge zone, to me it looks like a headache factory and thus I am going to remove it.

More likely, that should mean: certified for discharge in inland or near-shore waters EXCEPT in marked no-discharge zones. Something like that. No discharge is no discharge.

Anyway, you could ask Peggie for more opinion about your treatment system, before you decide to remove.

-Chris

[aquestaer]

Another option to consider is a composting toilet. When I signed up at my marina there was a requirement for "No Black Water Discharge". My boat didn't have a holding tank. I asked if a composting toilet would be acceptable and they had no issue. It was certainly a lot easier to install and weight is not an problem at all.

[a64pilot]

Lord don't try to build your own. No real savings and a real issue if it fails.
I couldn't find a Ronco tank that would fit, so I had a custom tank made by Triple M and am very happy with it, don't go aluminum either.

[LakeSuperior]

Your classic hull will list accordingly with the holding tank starts to fill. It is really annoying. In fact on my yawl the water tanks are star'b and the holding tank is port. When cruising the fresh water tanks empty and the holding tank fills. It is tough to move ballast on my boat so I tend to pump the tank on every opportunity.

[markpierce]

Not paying attention on balancing fuel between starboard and port fuel tanks resulted in this:

[Cheechako]

Install another 15 gal token tank wherever it fits. Don't use it. Whether you have 100 gal or 15 gal sooner or later you need to empty it, or alternatively, not use it.

[Dirk Williams]

Different direction, how about a composting toilet, would that work, short term, long term.

Dirk

[wrwakefield]

Hi Nick,

I agree re: Composting head. We replaced one of our two Lavac heads with one a couple years ago. [Lavacs are great heads- I just wanted to eliminate the need for a second holding tank... It can be quite limiting when you need to empty them...]

It has been great, and our guests think so too... [Even though they can use either head, one being a Lavac flush toilet, they always choose the Nature's Head '...because they don't have to pump it...'

If you are interested in learning more about how we made our decision, including photos and links to additional information and resources, here is the link to my page on this topic.

Best wishes with your new boat and head remodel.

Cheers! Bill

[BigNickMontana]

Originally Posted by peghall

The tank itself won't weigh that much, but water and waste weight 8.333 lbs/gal, so a full 30 gal tank can weigh upwards of 250 lbs.

Btw...Ronco Plastics (no relation to the VegoMatic Ronco) Ronco Plastics Marine Catalog is your best source for a tank. 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 several retailers who carry Ronco tanks--Plastic Mart and Raritan are two--but you can buy direct from Ronco for a lot less.

Peggie
"If you can't explain it to a six year old, you don't completely understand it yourself." --Albert Einstein
http://www.amazon.com/New-Get-Rid-Bo...dp/1892399784/

Great resource, just spent about 45 minutes going through the catalogue getting ideas.

They do have an under the floor tank that would work really well, but id have to pull up my floor to install it, that is a bit daunting as right now my floor is in great shape.

Next time I am at the boat I am going to break out the tape measure and see what I can fit where. Perhaps there is a solution yet to present its self.