Anyone have any recommendations or other wisdom to share on tank monitors like the one from Snake River Electronics?
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After sudden discovery
that our holding tank was full I installed a surge tank in the vertical section of the vent line with a sight tube beside it. the tank is four inch PVC pipe, two feet long, capped at each end and coupled to the 3/4 inch vent pipe. There is a Tee above and below the tank to allow a clear vinyl hose to lay parallel to the tank. The tank holds about four flushes and the grey water shows in the tube. No solids come into this area and so far it has worked well for about six years.
that our holding tank was full I installed a surge tank in the vertical section of the vent line with a sight tube beside it. the tank is four inch PVC pipe, two feet long, capped at each end and coupled to the 3/4 inch vent pipe. There is a Tee above and below the tank to allow a clear vinyl hose to lay parallel to the tank. The tank holds about four flushes and the grey water shows in the tube. No solids come into this area and so far it has worked well for about six years.
Ross, your gauge worries me a bit...
It has to mean that the contents of the "main" tank have to be VERY ripe, 'cuz NO air is getting into it via the vent...the "surge tank" blocks air flow in and out of the tank. It also prevents the methane, sulphur dioxide and other toxic flammable gasses generated in an anaerobic environment from escaping passively out the vent--a problem compounded by the amount head pressure needed to push gasses through the contents of the surge tank due to your tank location....the tank has be able to vent passively all the time, not just when flushing the toilet pushes gasses out. So while it may work ok (although I'm not sure anyone within 50' downwind of you when you flush the toilet would agree), I don't think it would pass a CG inspection, 'cuz CG regs require that all waste tanks be vented directly to the outside of the boat, but only your "surge tank" is. I think you'd need to put a second vent line on the holding tank to be in compliance with CG regs. It's certainly a unique approach, though! In nearly 20 years, I've never heard of anyone else doing what you've done. Btw, gray water is "galley, bath and shower water"...toilet waste is "black water."
It has to mean that the contents of the "main" tank have to be VERY ripe, 'cuz NO air is getting into it via the vent...the "surge tank" blocks air flow in and out of the tank. It also prevents the methane, sulphur dioxide and other toxic flammable gasses generated in an anaerobic environment from escaping passively out the vent--a problem compounded by the amount head pressure needed to push gasses through the contents of the surge tank due to your tank location....the tank has be able to vent passively all the time, not just when flushing the toilet pushes gasses out. So while it may work ok (although I'm not sure anyone within 50' downwind of you when you flush the toilet would agree), I don't think it would pass a CG inspection, 'cuz CG regs require that all waste tanks be vented directly to the outside of the boat, but only your "surge tank" is. I think you'd need to put a second vent line on the holding tank to be in compliance with CG regs. It's certainly a unique approach, though! In nearly 20 years, I've never heard of anyone else doing what you've done. Btw, gray water is "galley, bath and shower water"...toilet waste is "black water."
I think that I
Didn't make things clear enough. This tank in the vent line is in reality just a wide place in the vent line so that should the holding tank end up full before I can get to a pump-out I have a cushion and a visible indicator that it is time to put everthing else aside and find a pump-out. So far I have always gotten to the pump-out before there was a visual need to do so. I treat it rather like a fuse in an electric line. It warns me of an impending mess and lets me avoid it. The surge tank is only about a foot and a half above the top of the holding tank so any gases that evolve will not encounter more than one psi pressure and will be able to bubble free. This would never be treated as an extra day of capacity only as a spill preventer. In a simular manner I placed a Tee in a horizontal section of my fuel tank vent so that any fuel that might find its way into the vent line will be drained off into a small holding tank that is emptied before each refueling.
Didn't make things clear enough. This tank in the vent line is in reality just a wide place in the vent line so that should the holding tank end up full before I can get to a pump-out I have a cushion and a visible indicator that it is time to put everthing else aside and find a pump-out. So far I have always gotten to the pump-out before there was a visual need to do so. I treat it rather like a fuse in an electric line. It warns me of an impending mess and lets me avoid it. The surge tank is only about a foot and a half above the top of the holding tank so any gases that evolve will not encounter more than one psi pressure and will be able to bubble free. This would never be treated as an extra day of capacity only as a spill preventer. In a simular manner I placed a Tee in a horizontal section of my fuel tank vent so that any fuel that might find its way into the vent line will be drained off into a small holding tank that is emptied before each refueling.
I installed the Snake River system this year
and it works fine. Nothing difficult about the installation - just the normal crawling and bending and fitting into tight spaces. Calibration wasn't difficult, just some extra time at the pump-out to fill and flush an extra time to double-check. If you want to use the SR system for your diesel tank, you'll need to buy the $60 sensor.... and make sure your tank can take it. Peggy, Ross is obviously an engineer ;D Cheers, Bob s/v X SAIL R 8
and it works fine. Nothing difficult about the installation - just the normal crawling and bending and fitting into tight spaces. Calibration wasn't difficult, just some extra time at the pump-out to fill and flush an extra time to double-check. If you want to use the SR system for your diesel tank, you'll need to buy the $60 sensor.... and make sure your tank can take it. Peggy, Ross is obviously an engineer ;D Cheers, Bob s/v X SAIL R 8
Does anything ever sit in that tank?
If it does, the small amount of pressure created by gasses being generated in the holding tank isn't even to allow 'em to "bubble through" ANY amount of liquid in the vent line except when the toilet is flushed...and flushing the toilet isn't always enough, as plenty of people have found out when as little as half a cup of water or waste accumulates in a dip in their vent lines. Those gasses are gonna follow the line of least resistance, which in most cases is the head discharge line and out through the toilet. Methane (which is odorless) and sulphur dioxide (which isn't) are highly toxic...enough of an accumulation of either or boat in a closed up boat can even be lethal. You've had this arrangement for 6 years, so I doubt if I'm gonna convince you to change it. But it's not an approach I'd recommend. Besides, there are all kinds of 12v gauges that don't require sticking your head in the bilge to check a sight glass. Or even better yet...the discharge of treated waste is legal on the Bay...install a Lectra/San (Type I MSD that treats each flush and sends it overboard with -0- negative impact on the environment) and never have to worry about whether a tank is full again.
If it does, the small amount of pressure created by gasses being generated in the holding tank isn't even to allow 'em to "bubble through" ANY amount of liquid in the vent line except when the toilet is flushed...and flushing the toilet isn't always enough, as plenty of people have found out when as little as half a cup of water or waste accumulates in a dip in their vent lines. Those gasses are gonna follow the line of least resistance, which in most cases is the head discharge line and out through the toilet. Methane (which is odorless) and sulphur dioxide (which isn't) are highly toxic...enough of an accumulation of either or boat in a closed up boat can even be lethal. You've had this arrangement for 6 years, so I doubt if I'm gonna convince you to change it. But it's not an approach I'd recommend. Besides, there are all kinds of 12v gauges that don't require sticking your head in the bilge to check a sight glass. Or even better yet...the discharge of treated waste is legal on the Bay...install a Lectra/San (Type I MSD that treats each flush and sends it overboard with -0- negative impact on the environment) and never have to worry about whether a tank is full again.
I was careful to maintain a
slope in the vent line to ensure that even sloshed water in the vent line will drain back. I am sure that this arrangement includes some unusual methods and should any problems manifest themselves I will certainly take remedial action. The boat is well ventilated with cowl vents and fans powered by a dedicated solar panel. Methane is lighter than air and I know the odor of most sulfer compounds that might be present in a boat.
slope in the vent line to ensure that even sloshed water in the vent line will drain back. I am sure that this arrangement includes some unusual methods and should any problems manifest themselves I will certainly take remedial action. The boat is well ventilated with cowl vents and fans powered by a dedicated solar panel. Methane is lighter than air and I know the odor of most sulfer compounds that might be present in a boat.
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