Help on holding tank system design

[rls8r]

My boat has a Raritan Elegance toilet and the boat came with an ElectroScan treatment unit, but no holding tank. Since more places are going "No Discharge" - it's time for me to install a holding tank. I can fit a 15 - 16-gallon tank between the outer head bulkhead and the hull. I have questions about the design (see stylized diagram, below).

The plan is to arrange things so that, 1) untreated waste can go indirectly overboard by directing wastes from the toilet to the holding tank via the "Y" valve and opening the ball valve below the tank, 2) treated waste can go overboard by directing wastes from the toilet to the ElectroScan unit via the "Y" valve and opening the ball valve below the tank, or 3) treated waste can be collected in the holding tank by directing wastes to the ElectroScan unit via the "Y" valve and closing the ball valve below the tank.

I figure that I can use option 1 when I'm offshore, option 2 when I'm inshore but not in a "No Discharge" zone, and option 3 when I'm in a "No Discharge" zone. Having option 2 allows me to reduce the need for a greater amount of tank storage volume. Option 3 also helps reduce the holding tank volume needed since I can collect treated wastes while in the "No Discharge" zone and then release them when I'm outside of the zone.

My questions are:

1) does this seem like a good setup? If not, how to change it.
2) does the vented holding tank remove the need for a siphon break in the discharge line(s)?
3) is there some minimum length of hose needed between the tank and the deck pump out fitting (someone I talked with mentioned a concern with 'vapor lock')?

Thanks for your feedback!

[more]

Originally Posted by rls8r

1) does this seem like a good setup? If not, how to change it.


Thanks for your feedback!

no best all waste from toiled go to holding tank,mixing decomposting 1-2 days and then discharge.ant lot charter guest (99,99%) after dont see work in bow stop watering. and **** stuck in pipe ,

whit direct discharge always on wall of pipe slowly layer by layer something stuck special paper.

Ps
use zeva 3-5 layer paper and dont have any problem on toilet

[jamhass]

Get, and read, Peggy Hall's book:

https://www.amazon.com/New-Get-Rid-B...s%2C158&sr=8-1

It has all the good advice, from a pro, you will ever get. And... she is very approachable including on this forum.

[Plumbean]

Yup, Peggy is the expert. I have two vents on my holding tank, one on port and one on starboard. Helps maintain airflow due to pressure differential. Pretty sure that tip came from Peggy, and it has worked well.

[peghall]

Thanks for recommending my book, Jamhass! No book can answer every question...and I'm not only happy to answer the ones you're sure to have that my book doesn't, I have a couple of questions of my own that need answers before I can offer any advice.


The Raritan Marine Elegance is the top rated macerating electric toilet. It's designed to use onboard pressurized fresh water but adding a remote intake pump will allow it to use sea water. You have an ElectroScan which needs salt...does your toilet have a remote intake pump? If it doesn't, was a salt tank installed to supply it?


IMO, you've over-complicated your "sewage disposal" plan...I'll be glad to help you design a much simpler one that does everything you want it to do. (Btw, I don't charge anything to to help boat owners solve--better yet, prevent problems). If you'd like my help, just end me a PM.


--Peggie

[rls8r]

Hi Peggie -

Thanks! I have your book on order. And thanks to those who suggested it.

My Raritan does have a remote intake pump and a small salt tank (since most of the Chesapeake is brackish). I didn't show that on the drawing since I only drew the discharge system.

I'm on the boat now - working off my phone, which is awkward for me. I'm afraid that I've been struck with FFS (Fat Finger Syndrome) which makes typing on my phone's keypad difficult for me. I'll PM you tomorrow evening when I return home to my desktop computer (assuming that I can figure out how to do it).