Size of holding tank

[mako]

I recall my boat with 2 heads had a holding tank of about 50 gallons. Vacu-flush system so there were never any clogs. I lived aboard full time, and even with numerous guests it would last a week.

[BAD ORCA]

Originally Posted by ranger58sb

Well at least it sounds like yours is as efficient as you can get for a 22-gallon tank.




I've read "personal discharge" is usually approx 1 gal per person per day. (Might be worth checking that elsewhere.)

If true, though, 5 days and two persons would be about 10 gallons of effluent, slightly less than half of a 22 gallon tank. Space for another few days... and/or even an overnight guest or two. Probably just a matter of management.

And then there's that access to pump-out thing. We've usually been luck enough to encounter facilities en route while on longer trips. More management. Depends on area, I suppose...

-Chris

PHEW! ok great i just bought an 11 gallon poly tank (not installed yet) and was getting a little worried it might not be enough for weekends out to the islands by myself.

[David Mathis]

We usually spend only a couple days at a time at anchor, hardly ever more than four, then a few at a marina. Our 20 gallon holding tank is adequate for two people under these circumstances. The water tank">fresh water tank holds 100 gallons and the fuel tanks can hold 436 gallons. Since we're almost always inland where pump-out stations are common, the Y valve is sealed to prevent use of the macerator to pump overboard. As you probably know, the Y valve must be sealed when operating on many no discharge waterways. The size allows us to go about a week between pump-outs but we usually have the tank emptied when it gets to about half or a little over. With our cruising style, the holding tank size has never been an issue.

[peter loveridge]

15 gallons is a bit small but it is common. In Nova Scotia there are NO pump out facilities west of the LaHave river, and the one there is right at the top of the river. There are NO pump out facilities east of Halifax until you get to Cape Breton. The ones in Halifax and the Bras d'Or lakes usually work, the ones elsewhere often are out of order. I have seen in print , though I wouldn't like to attest to it in court, that you can empty your holding tank in any open water in an area with no pump out facilities as long as you are 1. on an ebb tide, 2 going at least 4 knots. And please bear in mind, there are many large open pen fish farms that discharge as much raw sewage as a 10,000 population small town, and every municipal sewage system discharges massive (compared to what comes out of boats) amounts of raw sewage every time there is a heavy rain. As far as I know, boat more than 30 years old are grandfathered and don't have to have MSDs. f there are "poop police " in Nova Scotia , in nearly 50 years of cruising, I have never seen one

[TrentePieds]

Dr.D said: "Hey, I am trying to investigate what is a reasonable size holding tank. Not meaning to create a standard. Geez, relax….."

If it ain't quantified, it don't count :-)!

Number of crew x number of bladder evacuations per man/woman per day x qty of liquid per evacuation x number of days elapsing twixt pump-outs. Add 12% for excreta.

There's yer minimum holding tank size.

Doesn't anybody know the volume of a "standard whizz" any more?

For them wot don't, measuring cups are cheap. Or just use an empty milk bottle. All done in the name of science.

TrentePieds

[goboatingnow]

My experience with a manual Jabsco , was 90 litres lasted 3-4 days of normal use. 2 people full time onboard.

[thinwater]

Originally Posted by Dr. D

My boat has a 22 gallon holding tank. When I found that out I thought that was on the small side. The diesel tank and fresh water tanks are each 34 gallon.

From what I now understand, my diesel tank is fine, but my fresh water tank is very limited.

OTOH, it seems many “cruising” boats have even smaller holding tanks. Is that because the designers figure their boats will be upon the open seas and discharging direct into the sea?

22 gal holding is a little small, but pump-outs are everywhere on the Chesapeake. (I'm out of Deale, MD) Mine are free, all of them are cheap.


Diesel is fine, freshwater could be bigger, certainly if you like staying on the hook and take showers. Maybe you can add something.

[fourlyons]

This family of four, living aboard full time would dependably fill a 50 gal tank every seven days. This was with a lavac head.

[thinwater]

Much depends on how much you use shore-side facilities. I don't just mean marina-dwelling, I mean all trips ashore. Fourlyons would be the max, but I agree that is realistic. But we seem to stop in a marina at least that often to fill water or something.

[FlyingScot]

The problem with a small holding tank is you will want to be skimpy on the flushing water, when in fact you should flush a lot of water behind liquid or solids to keep the hoses free and clear. Cleaning or replacing hoses is a job that no one looks forward to or enjoys.

Bathroom habits are very personal, some hardly pee all day and others drink a lot of fluids and pee 10 - 20 times per day. Huge difference in tank size needed.

Good luck!