Revised holding tank - Please comment

[Weyalan]

Here is the new version of the toilet and holding tank system, revised to take into account the wisdom and advice from the previous thread.

Again comments are welcome




Key
1. Bronze thru-hull 3/4"
2. Bronze sea-cock valve 3/4"
3. Toilet. 12v macerating
4. Anti-syphon loop with vent valve between pump and bowl
5. Y-valve, either takes sewage directly from toilet to thru-hull outlet, or from tank to thru-hull outlet
6. Anti-syphon loop with vent valve for outlet
7. Y-valve, either takes sewage from toilet to thru-hull oulet, or from toilet to holding tank
8. Bronze sea-cock valve 1" (?)
9. Bronze thru-hull 1" (?)
10. Holding tank
11. Pump, to pump sewage from holding tank to thru-hull outlet. type to be determined
12. Pump-out outlet
13. Vent for tank
14. In-line filter
15. Inspection / access port for tank
16. Flush-out inlet ( Flush-out outlet via pump-out outlet or via thru-hull outlet)

Hopefully this is a better arrangement than the previous?

I am still not sure whether it will be ok to go for 1" instead of 1.5", seeing as the sewage will get macerated straight from the toilet. I am also not sure what is going to be the appropriate type of pump for pumping out the tank to the thru-hull outlet.

[bill good]

Check the Aust Standards for specs. Email for more info.

Bill Goodward

[Wotname]

Nice drawing, what is the approx. volume of the holding tank?

[Weyalan]

Tank volume still to be determined, am aiming for 50-60 litres (13 - 16 gallons).

[Evan]

Ahh, the "Chernobyl" option. Just label all the valves pretty carefully... Why have valve 5? Get rid of it. Tee pump 11 into discharge seacock line. When you want to pump out by hand, make sure valve 7 is set to connect head to tank and thus pump can only discharge to seacock.

Make your discharge to deck connection 12 a top connection thru top of tank with an internal suction pipe. The more tank top connections you have, the less chance of a leak.

On my boat, it's going to be a bit simpler. Head goes straight to an above the waterline gravity tank. Discharge from bottom of tank to seacock. Where we will be, we'll alway be able to get far enough from shore to discharge at sea so no deck connection.

[Steve Pope]

I have plumbed mine with 2 seacocks, 2 x 3 way v/v's, 2 vented loops 3/4" and
1,1/2", and 1 breather that does all that is needed. I can't understand why you have the inlet going to the toilet before going to the vented loop, unless that is part of the macerating setup. ( Ihave a lavac so the pump acts as a macerator, sort of ) my inlet goes directly from the seacock to the vented loop and then to the toilet, I rely on the flushing water from the toilet to flush the holding tank rather than having no.16. Still your belt and braces system gives you 2 easy flushing options, with a 3rd using the lid on top of the tank.

[Boracay]

Your setup is complex with lots of valves and pipes. Going to be a right royal PITN to manage.

Why not do KISS? Run the toilet output to the top of the holding tank. Put a "T" on the outlet from the holding tank. One branch goes to the seacock, the other to the sewerage pumpout.

If you find you don't like it you can put all that complicated piping and valves in later.

[hooked on water]

This is rather interesting as am just starting to set mine up also - the tank anyway
am thinking at the moment of placement for all these lines
will keep watching
hey weyalan how is everything going there on the other side of the river
how have you gone in regards to your mast
have you thought of modifying the base of your mast to lower it yourself
only need to fit a hinge base adn use spinakar poles and winches to lower or raise it toward/from the stern
cheers
Greg

[Weyalan]

Hi Greg,

The mast is keel stepped, not deck stepped. It is 60' (18.3m) long. I don't think we are going to be able ot raise and lower it without the use of a crane.

Work is going well... we have ripped out the old dunny, plumbing, sink, etc and done the cutting out of bulkheads and fittings we are now at the fun stage of sanding and grinding (if pushing a angle grinder with 16 grit disc is "fun"). Once that is done, it gets really exciting - fibreglass and epoxy... wheeee!

[hooked on water]

Sorry , just a thought on it, sorry for the side track also
yeah just did that over my whole hull, inside and out
very sore shoulders and arms and neck and and and
finally started framing the floor, done the hardest frames, so the others should be done by the end of the week
also amazing how long it takes to epoxy putty all those joints of bulkheads andhow much epoxy they take
have extended my cabin, just need to finish the cockpit now
I am just also setting up the mast post in the cabin also
fixed the base, it was incorrectly built, was meant to be continuous and was only 6 inches high
so broke it open and welded a whole pile more steel in and remdered it back up, and added the further required ballast there also
fun in this land of floating work
Greg

[hooked on water]

you really are doing a very serious refit, did not think it was going to be this big
you are doing well
good luck, and we need that beer some time
cheers

[44'cruisingcat]

Is the bottom of the holding tank above the waterline? If it is, I think you could simplify this by a huge amount.

Simply go from the toilet outlet straight into the bottom of the tank where pump 11 is located. (You can get rid of pump 11 too) Have a 3 way valve in this line so you can discharge overboard or empty the tank overboard. Also a ball valve between this 3 way valve and the tank.

Add some breathers and a pump-out line (which could be T'ed into the line where pump 11 was) and you're all done.

The only caveat is that the ball valve I mentioned needs to be opened when flushing to the holding tank, and closed afterwards, to prevent sewage draining back into the toilet.

Emptying overboard is done by gravity.