Is it necessary to close the thru hull for the macerator discharge line when not discharging? Is there a one way valve in the pump which will stop any sea water from backflowing through the pump and filling the tank? It would be nice not to have to open and close the thru hull after every use. Any experience from leaving it open?
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I never do
I've had a 280 and now a 380 and I've never closed it. The macerator works just great, and no water has ever backed up. I would recommend yearly checking of all clamps and following Peggy's head maintenance plan, then no stinky surprises
Bob Knott S/V Serenity H380
I've had a 280 and now a 380 and I've never closed it. The macerator works just great, and no water has ever backed up. I would recommend yearly checking of all clamps and following Peggy's head maintenance plan, then no stinky surprises
Bob Knott S/V Serenity H380Vented Loop
I'm installing a macerator pump on my H34. My review of Calder and other sources say that you should have a vented loop, at least 18 inches above the water line, to prevent siphoning back into the waste tank. I don't think that any macerator pumps have a "one-way" valve, but, a "Y-valve" that directs from "pumpout" and "macerator" to the waste tank, if left in the "Pumpout" direction, should effectively close the through hull conection, even if the thru-hull is left open. But why not close it?
I'm installing a macerator pump on my H34. My review of Calder and other sources say that you should have a vented loop, at least 18 inches above the water line, to prevent siphoning back into the waste tank. I don't think that any macerator pumps have a "one-way" valve, but, a "Y-valve" that directs from "pumpout" and "macerator" to the waste tank, if left in the "Pumpout" direction, should effectively close the through hull conection, even if the thru-hull is left open. But why not close it?
First rule of good seamanship:
Keep ALL seacocks closed except when actually in use. ( And that includes toilet intake and direct overboard discharge seacocks...If they're not conveniently located to do that, move the thru-hull(s) the next time the boat is hauled.) Just how often do you dump your tank that it's such a "pain" to open and close that one each time? Yes...leaving it open can fill up your tank, which can run back to the toilet and overflow the bowl. It can ever sink your boat. Keep it closed except when you're actually dumping.
Keep ALL seacocks closed except when actually in use. ( And that includes toilet intake and direct overboard discharge seacocks...If they're not conveniently located to do that, move the thru-hull(s) the next time the boat is hauled.) Just how often do you dump your tank that it's such a "pain" to open and close that one each time? Yes...leaving it open can fill up your tank, which can run back to the toilet and overflow the bowl. It can ever sink your boat. Keep it closed except when you're actually dumping.
And ESPECIALLY the engine intake
People tend to leave the engine intake open, because they think it a hassle to close it after each use. But this one seacock is more dangerous than any other. Your raw water circuit likely involves five hoses, twelve or more hose clamps, a pump, and a heat exchanger, all below the waterline. Failure of any of these can result in outside water getting in. At the other end of the scale, your galley sink seacock likely has just one straight and short hose run from drain to seacock. This is no excuse to leave IT open, but it has few points of potential failure than your engine raw water circuit. One exception to the rule: if your cockpit scuppers exit below the waterline, leave those seacocks open. Otherwise, rain water won't drain to the sea, but instead will enter your boat through your cockpit fittings.
People tend to leave the engine intake open, because they think it a hassle to close it after each use. But this one seacock is more dangerous than any other. Your raw water circuit likely involves five hoses, twelve or more hose clamps, a pump, and a heat exchanger, all below the waterline. Failure of any of these can result in outside water getting in. At the other end of the scale, your galley sink seacock likely has just one straight and short hose run from drain to seacock. This is no excuse to leave IT open, but it has few points of potential failure than your engine raw water circuit. One exception to the rule: if your cockpit scuppers exit below the waterline, leave those seacocks open. Otherwise, rain water won't drain to the sea, but instead will enter your boat through your cockpit fittings.
it happens
I have had salt water siphon back into my aft holding tank (on a 410) after the macerator seacock was left open. Starboard tack with the rail down, et cetera.... The owner's manual, by the way, warns that this can happen. Close 'em up. I respectfully disagree with Peggy, however, regarding this being the first rule of seamanship. "Always keep a proper lookout" still seems a bit more urgent.
I have had salt water siphon back into my aft holding tank (on a 410) after the macerator seacock was left open. Starboard tack with the rail down, et cetera.... The owner's manual, by the way, warns that this can happen. Close 'em up. I respectfully disagree with Peggy, however, regarding this being the first rule of seamanship. "Always keep a proper lookout" still seems a bit more urgent.
Hair splitter
Are you suggesting folks should post a lookout in the head?)) By all means, keep a proper lookout underway...but an open seacock can wreak havoc in the slip when no one is aboard.
Are you suggesting folks should post a lookout in the head?
)) By all means, keep a proper lookout underway...but an open seacock can wreak havoc in the slip when no one is aboard.
Ahem
Agreed, Peggy. The one that I lose sleep over is the engine raw-water intake. A buddy of mine fried the twin 454s on his scarab because he forgot to open the seacocks, which is the type of thing I can really see myself doing. I leave that one open, therefore, unless I'm planning to leave the boat overnight. Adding a third bilge pump is on the project list, just to help me sleep at night with an open seacock. (When I dream, by the way, my 410 also has twin 454s. It's the latent stinkpot thing.)
Agreed, Peggy. The one that I lose sleep over is the engine raw-water intake. A buddy of mine fried the twin 454s on his scarab because he forgot to open the seacocks, which is the type of thing I can really see myself doing. I leave that one open, therefore, unless I'm planning to leave the boat overnight. Adding a third bilge pump is on the project list, just to help me sleep at night with an open seacock. (When I dream, by the way, my 410 also has twin 454s. It's the latent stinkpot thing.)
Let's make believe...
...you just came back from a wonderful sail, winds were perfect, seas were calm. You come back to your slip, shut off the electonics, secure the dock lines, wash up and change your clothes, and you and your first mate go out to dinner and a local seafood restaurant. Over dinner, you talk about that today was one of the ten best sails of the summer. You talk about how happy the new autopilot worked and you were glad you spent the money. After dinner, you take a ride to the beach and take a romantic stroll on the sand. About 4 hours later, you come back to your slip and "YIKES" your boat is gone, all you can see are the dorades and the mast sticking out of the water! You scream out "I should have closed all the seacocks!!!!" ........it doesn't take long. Get into the habit of closing them all, and then it will be no big deal. Roc
...you just came back from a wonderful sail, winds were perfect, seas were calm. You come back to your slip, shut off the electonics, secure the dock lines, wash up and change your clothes, and you and your first mate go out to dinner and a local seafood restaurant. Over dinner, you talk about that today was one of the ten best sails of the summer. You talk about how happy the new autopilot worked and you were glad you spent the money. After dinner, you take a ride to the beach and take a romantic stroll on the sand. About 4 hours later, you come back to your slip and "YIKES" your boat is gone, all you can see are the dorades and the mast sticking out of the water! You scream out "I should have closed all the seacocks!!!!" ........it doesn't take long. Get into the habit of closing them all, and then it will be no big deal. Roc
On The Bottom
When you see your friend's moored sailboat masting sticking 30 or so feet out of the water in 20 plus feet of salt water, you will quickly make closing the seacocks a part of your priorites when leaving the boat for the weekend or any extended period of time. In this case, a rather small hole caused by abrasion on the intake head hose was the culprit. When you see a fairly new sailboat gutted out to bare fiberglass having the interior replaced because of this, it will reinforce this procedure. Closing every thru-hull before we leave the boat has become a simple procedure as is opening all of the ones we need when we come to the boat. Since you should not be using the macerator discharge, why would you even want to think about leaving them open, and yes they will in many case back-siphon water filling up the holding tank and even overflowing the head. Why take the chance, close them when leaving the boat for extended periods of time. Better to be safe than sorry.
When you see your friend's moored sailboat masting sticking 30 or so feet out of the water in 20 plus feet of salt water, you will quickly make closing the seacocks a part of your priorites when leaving the boat for the weekend or any extended period of time. In this case, a rather small hole caused by abrasion on the intake head hose was the culprit. When you see a fairly new sailboat gutted out to bare fiberglass having the interior replaced because of this, it will reinforce this procedure. Closing every thru-hull before we leave the boat has become a simple procedure as is opening all of the ones we need when we come to the boat. Since you should not be using the macerator discharge, why would you even want to think about leaving them open, and yes they will in many case back-siphon water filling up the holding tank and even overflowing the head. Why take the chance, close them when leaving the boat for extended periods of time. Better to be safe than sorry.
Another reason to close it
If you leave the macerator seacock open and someone accidentally flips the wrong breaker on (macerator) while you are tied up at a fancy marina, it wouldn't be a pretty sight and highly illegal even to accidentally dump waste. I always close my seacocks when I leave the boat even though the one under the galley sinks mean removing stuff to get to it. I always keep the macerator output seacock closed except for the brief time when dumping offshore.
If you leave the macerator seacock open and someone accidentally flips the wrong breaker on (macerator) while you are tied up at a fancy marina, it wouldn't be a pretty sight and highly illegal even to accidentally dump waste. I always close my seacocks when I leave the boat even though the one under the galley sinks mean removing stuff to get to it. I always keep the macerator output seacock closed except for the brief time when dumping offshore.
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