Macerator vs non-macerating discharge pump

[Peggie Hall HeadMistress]

I've always preferred Whale y-valves...among other reasons: they can mounted on the side of a vanity with the valve inside and only the handle showing...which makes that an accessible location that isn't a clunky piece of equipment stuck in hose out of sight, and a PITA to access.

Where will your tank sit in the boat...forward or aft? next to the hull or on the centerline? How much clearance above the tank will you have? 1.5" 90s need at least 5". Vent line diameter? How long?

--Peggie

 

[malyea]

The tank is centerline under fwd V berth with only 1” clearance on top of tank with current setup and 14 gal tank.

Think I will have both ingress and egress waste lines plumbed into the tank side (not the top) then elbow internally to a vertical standpipe for discharge pickup. (Photo 1 shows ingress and egress lines currently with red arrows and I’ll have the egress line raised on the side as indicated by the red dot).

I’ll mount the Dometic T pump horizontally on the compartment bulkhead just aft of the tank (red box in photo 2).

 

[malyea]

#1 arrow is deck pump out line
#2 arrow is waste ingress line into tank direct from head
#3 arrow is waste discharge line to the pump then to thru hull

All tank fittings will be as high on the tank side as possible. (Not enough clearance to have the openings on the tank top)

 

[Peggie Hall HeadMistress]

It looks like you may have room for a somewhat triangular shaped tank, 'cuz there's a good bit of space on both sides of the tank in your photos...and spreading it out a bit may lower the height enough to give you the clearance you need to put the fittings on the top of it. As you go through the drawings in the Ronco catalogs, you may not realize that tanks can be oriented in any direction 'cuz there is no top or bottom until the fittings go in, and you decide where they go. So rotate, flip end-for-end, front-back...you might be surprised at all the options you'll find.

I just realized that you neglected to include a vent fitting in your list. Vents are essential! It should be 1", which will require replacing the vent thru-hull with an open bulkhead aka "mushroom" fitting. The provides much better air exchange and also lets you prevent vent blockages by sticking a hose nozzle against it to back flush the vent line every time you wash the boat. All the details are in my book.

--Peggie

 

[jviss]

I've always preferred Whale y-valves...among other reasons: they can mounted on the side of a vanity with the valve inside and only the handle showing...which makes that an accessible location that isn't a clunky piece of equipment stuck in hose out of sight, and a PITA to access.

The same is so for Bosworth Y-valves, which is what was on my boat:

Bosworth Company - Y Valves

 

[NYSail]

In my opinion, depends on the toilet(s) you have. I have two electric and they chew things up pretty well. I recently took out both masceraters and have gravity discharge. Everything goes into tank and if I need to empty just open a valve. One less motor to worry about..... open a Valve and away it goes. Off shore only of course!

Greg

 

[jviss]

In my opinion, depends on the toilet(s) you have. I have two electric and they chew things up pretty well. I recently took out both masceraters and have gravity discharge. Everything goes into tank and if I need to empty just open a valve. One less motor to worry about..... open a Valve and away it goes. Off shore only of course!

Greg

Is there a pumpout service nearby?

 

[malyea]

.....I recently took out both masceraters and have gravity discharge. Everything goes into tank and if I need to empty just open a valve. One less motor to worry about..... open a Valve and away it goes. Off shore only of course!

Greg

I like the idea of simple gravity discharge but I suppose the holding tank would need to have the discharge port tapped on the tank side at the bottom and I’d prefer the tank port to be high on the tank...but I do like simplicity....

 

[NYSail]

Pump out service in port always available.

Yes I conversed the tank so gravity discharge is from bottom....... deck pump out from top / pick-up tube that gets most everything..... I’ve checked. Simple and no stinkin’ y valves.

 

[Peggie Hall HeadMistress]

There's one other little detail: the entire tank has be entirely above waterline to drain via gravity. If any of it is below waterline, sea water would flood the tank at least to the waterline instead of draining when the thru-hull is open.

--Peggie

 

[malyea]

There's one other little detail: the entire tank has be entirely above waterline to drain via gravity. If any of it is below waterline, sea water would flood the tank at least to the waterline instead of draining when the thru-hull is open.

--Peggie

And I'd prefer to not have a discharge hole at the bottom of the holding tank in the event of fitting/hose failure (although my current tank has a hole at the bottom...).
I'll check the waterline issue but even then I'm torn between 1) simple gravity discharge but a big mess if the fitting or hose fails (really...how likely!?) and 2) nice to have the discharge hole near the tank top but at the expense of pump maintenance/leaks...
I'm gonna' have to drink a little on this one... (Books been ordered and shipped - maybe rum and a good read is in order).
Thanks all!

 

[malyea]

Bottom of tank measures 2” above waterline.

...and I presume the boat must be moving thru the water such that Venturi effect causes suction to evacuate the tank...

...back to leaning towards installing a discharge pump...

Pass the rum plz

 

[Peggie Hall HeadMistress]

The sun is now over my yardarm too and I'm definitely ready for a stiff scotch...Salut!

--Peggie