Holding tank: best location for hose in PVC plumbing

[ephyraboater]

[QUOTE=sailful;1370756]If you can do it don't make the tank a rectangle. /QUOTE]

I hear you. But it's an existing locker, all-squared sides etc. There will have to be some residual "stuff". (And I bought the tank to maximize volume in this locker - instead of custom, rounded fit etc, the 16 gal Ronco tank was ~$130 before shipping).

[Roy M]

When you build your rectangular box, on the inside, merely use epoxy, thickened with low density microballoons to give a moldable texture, to make filleted vertical corners and a rounded bottom that slopes to the drain pipe (if you are using a gravity drain). Then, in appropriate locations, you can simply flush the toilet, it drops into the tank, and drains out overboard. A couple of extra pumps helps to rinse out the interior of the tank. I use a beer can, much more available than soda cans in my work area, as the tool to establish the proper radius of the fillets. Then, before the epoxy sets, dip your fingers in some water and "massage" the epoxy surface to eliminate all ridges, hollows and other imperfections to make a finish that is absolutely mirror smooth.

[Cheechako]

I've not had good results with most PVC valves, for the reason mentioned, seize up and the shaft snaps off. I'm a bronze guy when it comes to valves. But if you use plastic valves get some good industrial types.... not avail at hardware stores. and not inexpensive. I dont remember the names but the good ones disassemble.

[goboatingnow]

personally having some a few installs and seen far too many others, I dont like any fittings on the underside of any tank , least of all a holding one, it always seems a leakprone area and often very hard to get at.

I now always pump my holding tanks via a mascerator pump, or manual pump ( least preferred).

Gravity based holding tank discharges have always seemed to give me problems and often block for no reason. Ive seen situations where the solids remain and the liquid drains out and the solids act like a plug.

dave

[CarlF]

I agree that you should put an access port on the top of the tank above the T fitting so you can push a stick through (make sure the "T" is oriented as a straight shot to the sea cock. The alternative is to push the stick up from under the boat with your face 6" from the outlet

The Trident 101/102 hose is just amazing. I've had mine for over six years with no smell. I know others who have had it much longer. I just wouldn't worry that much about odor permeation. Has anyone out there had odor permeation with this hose?

I'd also get rid of that ball valve under the tank. It's more likely to cause troubles than the hose odor permeation you're hoping to prevent.

The only Marlon valves I'll use are the OEM Series 93 Series. The others all get stiff and the handles sometimes break but the OEM's don't seem to have this problem. Forespar makes a OEM series valves for holding tank discharge with a built in spot for a wire tie to make the CG happy.

[ephyraboater]

Thanks to all for input. I should note that I'm going forward with my basic plan (rectangular tank, gravity option, all outflow from bottom, modified via forum input). My new Ronco tank is thick-walled with strongly-installed "factory" thread fittings.

My original question remains:
If I put a short (ca. 1-1.5') length of premium quality (Trident 102) hose horizontally from head to the vertical PVC pipe (ca. 2.5-3') going into tank, is that "smart" regarding where effluent will sit? Or, is it better to put the flexible hose on the vertical run to the tank?

[ephyraboater]

Originally Posted by CarlF

... alternative is to push the stick up from under the boat with your face 6" from the outlet

The Trident 101/102 hose is just amazing. I've had mine for over six years with no smell. I know others who have had it much longer. I just wouldn't worry that much about odor permeation. Has anyone out there had odor permeation with this hose?

I'd also get rid of that ball valve under the tank. It's more likely to cause troubles than the hose odor permeation you're hoping to prevent....

Unless I hear of real permeation issues with Trident 102 (i.e., within ca. 5yr of install), what you (and others) say reinforces my thoughts that I should a) not use a valve between tank and seacock (drain), and b) not go with horizontal PVC from head to vertical (hose) route to tank (instead, just use a short hose from head, using existing Jabsco hose barb, then all PVC, as I originally planned).

I may be over thinking all this, but just want to do the best, most easily maintained, system. And the forum has improved at least 2 vital aspects - Tee from gravity drain to pumpout, and not use a drain valve. Thanks all! And any more insights always welcome...

[Sailmonkey]

I used the PVC valve to keep waste from sitting in the hose. You know how that worked out for me. My other concern was letting waste pack into an extended section of relatively small space (the hose run).

[Cheechako]

I had no trouble with waste packing, in fact, I guess due to the wave action etc, as far as I could tell the waste seemed always to be like diarrhea. I tended to flush out with water pumped from the toilet after each pumping. Ill egal I suppose. Prior to summer storage, I flushed with a hose into the tank and back flushed the vent with a hose also..