Questions about converting a water tank to a holding tank: In November I posted a message about plans to install a 15 gal holding tank (biggest I could fit without major surgery)and questioned what to do with the 30 gal bow water tank that I don't need. Peggie responded with a suggestion to consider converting the water tank to a holding tank and a note that I needed more info before I started. I was late at getting my response back and lost my position in the discussion, thus not getting the more info needed. I'm trying now to pick up where I left off in November: Where can I find fittings for the tank to convert it? How can I assess the tank integrety? Are there any specific findings that will tell me the tank is not good for this? Does it matter whether the inlet to the tank is near the center or off to the side? (flat top, same hieght either way) Is there an easy way to measure the thickness without cutting into it? I assume the hose run from the antisiphon loop to the tank has to be a continous downhill run. If this seems impossible is the deal off or is there a way to allow for a low spot in the hose? I'm sure I'll think of more questions if this project starts to take form, but that's all for now. I'm going to Strictly Sail Chicago next week. It looks like there's no exhibitors dealing with this sort of thing, but does anyone know of any vendor there that I should talk to about my sanitation project? Thanks Geoff
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Answers to your questions
"Where can I find fittings for the tank to convert it?" If the tank has an inspection port (if not, you'll need to retrofit one...no harder than installing new fittings), all you need is at least one standard bulkhead fitting. "Are there any specific findings that will tell me the tank is not good for this?" It must be plastic, and ideally, have walls at least 1/4" thick. The thicker the better. "Does it matter whether the inlet to the tank is near the center or off to the side? (flat top, same hieght either way)" No. However closest to the centerline of the boat is better than closest to the hull. " Is there an easy way to measure the thickness without cutting into it? " Disonnect a hose...stick your finger in the hole and take a rough estimate between your thumb and finger. It's NOT rocket science...it's either a lot thinner than 1/4" or it's close...or it's thicker. "I assume the hose run from the antisiphon loop to the tank has to be a continous downhill run. If this seems impossible is the deal off or is there a way to allow for a low spot in the hose?" Flush clean water through the hose at least once a day to rinse out any waste left standing in it. If the tank is more than about 6' from the toilet, forget the whole idea.
"Where can I find fittings for the tank to convert it?" If the tank has an inspection port (if not, you'll need to retrofit one...no harder than installing new fittings), all you need is at least one standard bulkhead fitting. "Are there any specific findings that will tell me the tank is not good for this?" It must be plastic, and ideally, have walls at least 1/4" thick. The thicker the better. "Does it matter whether the inlet to the tank is near the center or off to the side? (flat top, same hieght either way)" No. However closest to the centerline of the boat is better than closest to the hull. " Is there an easy way to measure the thickness without cutting into it? " Disonnect a hose...stick your finger in the hole and take a rough estimate between your thumb and finger. It's NOT rocket science...it's either a lot thinner than 1/4" or it's close...or it's thicker. "I assume the hose run from the antisiphon loop to the tank has to be a continous downhill run. If this seems impossible is the deal off or is there a way to allow for a low spot in the hose?" Flush clean water through the hose at least once a day to rinse out any waste left standing in it. If the tank is more than about 6' from the toilet, forget the whole idea.
Thanks
That helps. The tank is approximately 5 feet from the toilet, but that means, perhaps, 8 feet of hose. If the antisiphon loop is close to the head can I count my 6 feet from the discharge end of the loop? That would be close to 6 feet. There is at least 3 feet just in the up and down for the antisiphon loop. (Boat is 4 1/2 hours away; will not be back for precise measurements 'til March) There is an inspection port but I assume the water hose fittings are too small for this purpose. (outlet is 1/2"ID hose. Inlet, I think, 3/4") I've not seen fittings for the inlet and outlet hoses in the catalogues. Can I use plumbing supply fittings? Is there a source for marine quality fittings? Can these rotmolded (or whatever they are) tanks be flued with acetone just like PVC? Thanks for your help. Geoff
That helps. The tank is approximately 5 feet from the toilet, but that means, perhaps, 8 feet of hose. If the antisiphon loop is close to the head can I count my 6 feet from the discharge end of the loop? That would be close to 6 feet. There is at least 3 feet just in the up and down for the antisiphon loop. (Boat is 4 1/2 hours away; will not be back for precise measurements 'til March) There is an inspection port but I assume the water hose fittings are too small for this purpose. (outlet is 1/2"ID hose. Inlet, I think, 3/4") I've not seen fittings for the inlet and outlet hoses in the catalogues. Can I use plumbing supply fittings? Is there a source for marine quality fittings? Can these rotmolded (or whatever they are) tanks be flued with acetone just like PVC? Thanks for your help. Geoff
Inlet should be ok...
Standard inlet size for all tanks is 1.5" ID. Holding tank outlet is also 1.5" ID. The fittings you need are in all the catalogs...they're in the thru-hull section, not the plumbing section. What you want are bulkhead fittings...they're threaded...a nut tightens against the hull, bulkhead, or tank wall to seal it. Do NOT use ANY sealant, cement, pipe dope etc. What do you mean by "flued with acetone?"
Standard inlet size for all tanks is 1.5" ID. Holding tank outlet is also 1.5" ID. The fittings you need are in all the catalogs...they're in the thru-hull section, not the plumbing section. What you want are bulkhead fittings...they're threaded...a nut tightens against the hull, bulkhead, or tank wall to seal it. Do NOT use ANY sealant, cement, pipe dope etc. What do you mean by "flued with acetone?"
Did I say "flued"?
I meant "glued" with acetone. But I think you answered that question. Again, thanks. You've helped a lot. When back at the boat I will look into this. If it doesn't seem to work I'll have to stay with the 15 gal tank for now. Geoff
I meant "glued" with acetone. But I think you answered that question. Again, thanks. You've helped a lot. When back at the boat I will look into this. If it doesn't seem to work I'll have to stay with the 15 gal tank for now. Geoff
A vent is sometimes called a flue, although
not very often in a marine context. I thought you were referring to a really esoteric concept I'd never heard of!
not very often in a marine context. I thought you were referring to a really esoteric concept I'd never heard of!
Nothing esoteric...
at least about sailing. I'm at about 4th grade level. I'll probably be back after I get going on this project. Again, Thanks Geoff
at least about sailing. I'm at about 4th grade level. I'll probably be back after I get going on this project. Again, Thanks Geoff
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