*oI just replaced holding tank vent line on '94 C270, I have seen solutions others use to reduce hose to fit stanchion but am unable to locate. Factory used water hose (the clear stuff) and it appears they heated the end of the line to make it sort of reduce & fit stanchion "bolt". I used the white vinyl reinforced vacuum line because the old hose had kinked at unavoidable tight bend right at the tank, thought the vinyl line would not be so apt to kink. There is too little clearance between stanchion bolt and hull for me to thread an increaser on it so I thought I would try a smaller hose on the stanchion and a barbed increaser into the 3/4" vent line. Anyone know what size hose will fit the stupid hollow bolt on the stanchion, hope to do this in one place but may have to do a couple steps to increase.
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Peggie Hall/HeadMistress
Get the vent out of the stanchion
Catalina is the only production boatbuilder I know of that runs holding tank vent lines into stanchions, and it's a VERY bad idea--the slit in the stanchion is so small that it clogs very easily, and it doesn't let nearly enough air to pass either direction. Install a thru-hull in the hull right below the toe rail and put a clamshell over it. A tight bend at the tank is not unavoidable and must BE avoided, 'cuz any hose will kink if it's bent too tightly....and a kink will create a blockage in the vent line that will make it impossible to pumpout the tank...flushing will pressurize the tank. Either one can result in a cracked tank or worse. Replace the straight fitting with an elbow fitting and install the thru-hull Any hose will kink if you bend it too tight. Then install the thru-hull in a location that will give you a straight thru-hull. If necessary, use an elbow thru-hull fitting.
Catalina is the only production boatbuilder I know of that runs holding tank vent lines into stanchions, and it's a VERY bad idea--the slit in the stanchion is so small that it clogs very easily, and it doesn't let nearly enough air to pass either direction. Install a thru-hull in the hull right below the toe rail and put a clamshell over it. A tight bend at the tank is not unavoidable and must BE avoided, 'cuz any hose will kink if it's bent too tightly....and a kink will create a blockage in the vent line that will make it impossible to pumpout the tank...flushing will pressurize the tank. Either one can result in a cracked tank or worse. Replace the straight fitting with an elbow fitting and install the thru-hull Any hose will kink if you bend it too tight. Then install the thru-hull in a location that will give you a straight thru-hull. If necessary, use an elbow thru-hull fitting.
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Ted
Thanks Peggy
Okay, I guess I was being lazy, but who wants to mess with their holding tank on a warm sunny winter day in So. Cal. I recognized that putting in an elbow was the best solution but didn't want to make another trip to the hardware store, I will do so. Was hoping to make stanchion work but as you pointed out I never could figure out why they used 3/4" hose if it only went to the very small opening in stanchion. Because macerator, tank and thru hull are below waterline won't the tank fill thru pump if it is off & seacock open ? Seems like only thing to prevent is the pump impeller and that depends on where the vanes are when it stops?
Okay, I guess I was being lazy, but who wants to mess with their holding tank on a warm sunny winter day in So. Cal. I recognized that putting in an elbow was the best solution but didn't want to make another trip to the hardware store, I will do so. Was hoping to make stanchion work but as you pointed out I never could figure out why they used 3/4" hose if it only went to the very small opening in stanchion. Because macerator, tank and thru hull are below waterline won't the tank fill thru pump if it is off & seacock open ? Seems like only thing to prevent is the pump impeller and that depends on where the vanes are when it stops?
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Peggie Hall/HeadMistress
How are you measuring hose?
Because hose wall thicknesses vary widely, hose sizes are always the inner diameter...and the "standard" size for all tank (water, fuel and waste) vent hose is 5/8". I'd be surprised if Catalina used any other size. Yes, your tank will fill up if the thru-hull is left open. The pump will not prevent water from being pushed through it into the tank (vane positions have nothing to do with it)...nor will it prevent slow seepage while the boat sits. Which is why the thru-hull should ALWAYS be kept closed except when actually dumping the tank, Seacocks left open when no one is aboard are the #1 cause of boats sinking in their slips...but even while aboard, open head intake and tank discharge seacocks can cause one hell of a mess to clean up. There should also be a vented loop in the line between the pump and thru-hull that's above the waterline at any angle of heel. And if there's only a tee fitting in the pumpout hose, it should be replaced with a y-valve. When the toilet is below the waterline--which yours is--there should also be a vented loop in the head intake (it has to go between the pump and the bowl, not between the thru-hull and the pump)...'cuz when the seacock is open, the only thing preventing water outside the boat from seeking its own level inside the boat via the toilet bowl is the wet/dry valve...and if you're relying on that, you're relying on a valve that has a high failure rate. People have an even higher failure rate about making sure it's left in the dry position. However, while the vented loop will keep water out of the bowl when the boat's at rest, it won't prevent water from being forced past it when the boat's underway on the same tack as the thru-hull...which is why the intake thru-hull should also always be kept closed except when the toilet is actually in use. But since boatbuilders in recent years have put decor ahead of safety and therefore have taken to hiding seacocks in locations that make it so impractical as to be impossible to keep them closed except when actually in use, it may be necessary to install a shutoff valve in the head intake line that IS readily accessible when using the head. And finally, all sanitation hose connections should be double clamped, with the screws on opposite sides of the hose. If you used only one clamp, you need to add another one to every connection. It's a lot of work to do it right, but it's always cheaper and easier to do it right the first time than it is to do it over after a disaster.
Because hose wall thicknesses vary widely, hose sizes are always the inner diameter...and the "standard" size for all tank (water, fuel and waste) vent hose is 5/8". I'd be surprised if Catalina used any other size. Yes, your tank will fill up if the thru-hull is left open. The pump will not prevent water from being pushed through it into the tank (vane positions have nothing to do with it)...nor will it prevent slow seepage while the boat sits. Which is why the thru-hull should ALWAYS be kept closed except when actually dumping the tank, Seacocks left open when no one is aboard are the #1 cause of boats sinking in their slips...but even while aboard, open head intake and tank discharge seacocks can cause one hell of a mess to clean up. There should also be a vented loop in the line between the pump and thru-hull that's above the waterline at any angle of heel. And if there's only a tee fitting in the pumpout hose, it should be replaced with a y-valve. When the toilet is below the waterline--which yours is--there should also be a vented loop in the head intake (it has to go between the pump and the bowl, not between the thru-hull and the pump)...'cuz when the seacock is open, the only thing preventing water outside the boat from seeking its own level inside the boat via the toilet bowl is the wet/dry valve...and if you're relying on that, you're relying on a valve that has a high failure rate. People have an even higher failure rate about making sure it's left in the dry position. However, while the vented loop will keep water out of the bowl when the boat's at rest, it won't prevent water from being forced past it when the boat's underway on the same tack as the thru-hull...which is why the intake thru-hull should also always be kept closed except when the toilet is actually in use. But since boatbuilders in recent years have put decor ahead of safety and therefore have taken to hiding seacocks in locations that make it so impractical as to be impossible to keep them closed except when actually in use, it may be necessary to install a shutoff valve in the head intake line that IS readily accessible when using the head. And finally, all sanitation hose connections should be double clamped, with the screws on opposite sides of the hose. If you used only one clamp, you need to add another one to every connection. It's a lot of work to do it right, but it's always cheaper and easier to do it right the first time than it is to do it over after a disaster.
T
Ted
It's 5/8 's
Am I reading you correctly that there should be a vented loop in line from Macerator to thru-hull? The pump is mounted to tank with inlet threaded into tank, hose is 12" to seacock ~ 9" away. The tank pumpout is separate line from other side of tank so no Tees. There was not a loop in vent line (to prevent gravity flow into tank when terminus underwater?) & I'll have to look but willing to bet there is none on toilet intake either. Hafta get the book I guess, more involved than 3 golden rules of plumbers which are: 1. Water flows downhill 2. Sh** floats, usually 3. Payday is Friday
Am I reading you correctly that there should be a vented loop in line from Macerator to thru-hull? The pump is mounted to tank with inlet threaded into tank, hose is 12" to seacock ~ 9" away. The tank pumpout is separate line from other side of tank so no Tees. There was not a loop in vent line (to prevent gravity flow into tank when terminus underwater?) & I'll have to look but willing to bet there is none on toilet intake either. Hafta get the book I guess, more involved than 3 golden rules of plumbers which are: 1. Water flows downhill 2. Sh** floats, usually 3. Payday is Friday
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Peggie Hall/HeadMistress
Yep...there should be...
CG and ABYC safety standards call for vented loops in all hoses connected to below-waterline thru-hulls. It's not as critical to have one in sink drains, but when the thru-hull, tank and toilet (or any of 'em, but especially when they all are) are all below the waterline, they're essential. It's also essential to keep those seacocks closed except when actually in use. I've been on sailboats on which water forced up an open head intake seacock overflowed the bowl 'cuz somebody forgot to leave the head in the "dry" mode...and more people than I can count have asked me why their holding keeps filling up with sea water. Yep, I agree that you should get the book...'cuz there are a few more rules than just 3, and those 3 don't necessarily work the same way on a boat that they do on land. Rule 1: Stuff does flow downhill, but downhill on a sailboat can change. (No comment about 2 and 3) Rule 4: Water always seeks its own level. When it comes to boats, water outside the boat will use any open hole in the boat below the waterline to seek its own level inside the boat. Rule 5: The more water inside the boat, the higher waterline. A high enough waterline is commonly referred to as a sinking. There are more... A vented loop will only do two things: break any siphon started, and put an arch in the line above the waterline...water will only rise in the hose TO the waterline when the boat is at rest. It will NOT prevent an effect known as "ram water"--water pushed up a hose throught an open thru-hull by the pressure of the hull against the water when the boat is underway. So installing vented loops will not allow you to leave seacocks open, but only will prevent flooding while you're aboard at the dock or on an anchor.
CG and ABYC safety standards call for vented loops in all hoses connected to below-waterline thru-hulls. It's not as critical to have one in sink drains, but when the thru-hull, tank and toilet (or any of 'em, but especially when they all are) are all below the waterline, they're essential. It's also essential to keep those seacocks closed except when actually in use. I've been on sailboats on which water forced up an open head intake seacock overflowed the bowl 'cuz somebody forgot to leave the head in the "dry" mode...and more people than I can count have asked me why their holding keeps filling up with sea water. Yep, I agree that you should get the book...'cuz there are a few more rules than just 3, and those 3 don't necessarily work the same way on a boat that they do on land. Rule 1: Stuff does flow downhill, but downhill on a sailboat can change. (No comment about 2 and 3) Rule 4: Water always seeks its own level. When it comes to boats, water outside the boat will use any open hole in the boat below the waterline to seek its own level inside the boat. Rule 5: The more water inside the boat, the higher waterline. A high enough waterline is commonly referred to as a sinking. There are more... A vented loop will only do two things: break any siphon started, and put an arch in the line above the waterline...water will only rise in the hose TO the waterline when the boat is at rest. It will NOT prevent an effect known as "ram water"--water pushed up a hose throught an open thru-hull by the pressure of the hull against the water when the boat is underway. So installing vented loops will not allow you to leave seacocks open, but only will prevent flooding while you're aboard at the dock or on an anchor.
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