Help Need Your Input - Waste Tanks

[Capt Ron]

Dear Fellow Rinker Owners, I need your help in making Rinker realize they have a design flaw with their Vacu-flush plastic holding tanks. Has anyone who owned a vacu-flush system ever take a look at their waste tank after a pump out? The tank on my new 320 implodes after a pump out every time. Rinker says the vent is plugged. This was checked and everything is clear. Have any of you had waste tank failures or have experienced this issue please respond to this thread. Here are photos of my tank after a a couple of days. I just recently pumped it out yesterday and it was completely imploded and out of it's mounts. Thanks in advance.
Cheers,
Ron

http://i283.photobucket.com/albums/kk28 ... etank3.jpg
http://i283.photobucket.com/albums/kk28 ... etank2.jpg
http://i283.photobucket.com/albums/kk28 ... etank4.jpg

[frodo13056]

Ron,
I have a 2008 320 with the vacu-flush head. I've only pumped out twice this season but during my second pump out last weekend, the pump station pump shutdown during the middle of the pump out. I didn't notice that the pump out station pump had stopped and was watching the pump out hose sight glass and noticed that the waste was flowing BACK INTO the boat waste tank......
So, the ONLY way that this could have happened was for the boat waste tank to be at a negative pressure (under a vacuum) and the only way to create that much of a vacuum is that I was removing liquid at a much faster rate than air was being moved into the vacated liquid space.
 I closed the waste tank hose suction valve and as I removed the nozzle, air immediately sucked into the boat waste tank.  I checked my waste tank and it wasn't distorted but probably only due to the fact that the pump out station pump shut down on it's own - otherwise I'm sure that I'd have the same issue as you have.
After I restarted the station vacuum pump, I was able to empty the waste tank but again, when I went to remove the nozzle, same thing happened - air was sucked into the boat waste tank - again clearly indicating that the boat waste tank was at a vacuum. The only way to get the boat waste tank at a vacuum is that the vent line clearly isn't working properly - it's either undersized or partially blocked.
I haven't notified my Dealer yet but will the coming week. For Rinker (or anyone else) to suggest that the vent line is plugged is ridiculous - if that were the case, then your head would not flush at all - or you'd have exploded your waste holding tank, hoses, fittings, etc. Simple physics - the only way to move volume X from your boat head is to move it to another location - the waste tank (or overboard or the bilge). In order for you to move volume X to another location you either have to vent off a corresponding amount of air or you will pressurize the waste holding tank and if there was no vent line or the vent line is plugged, you'd eventually over pressurize the tank and KABOOM! You'd have a real mess on your hands, assuming that the vacu-flush system could create that much of an over pressure scenario (and I doubt that it could). If the vent line is PARTIALLY plugged or undersized, then the pressurized waste tank will eventually return to atmospheric pressure after each flush. I'm guessing that if you did a series of rapid flushes, your waste tank would pressurize and probably re-form to it's original condition. I doubt that you could flush that fast since it takes a minute or two for the vacu-flush vacuum pump to create another vacuum volume for another flush.
You could try and fill the waste tank with water from the pumpout station while holding something over the hose to keep air from coming out that way - and see if any air comes out the vent line - that's what I'll do when the dealer says that the vent line is plugged. My guess is that the vent line is partially plugged or undersized. If you pressurize your tank by filling it with water, it'll return to it's normal size but you'll need to figure out where the vent line is plugged (or partially plugged).
I'll let you know what my dealer says / finds since mine is still under warranty.

Steve

[Babyboomer]

I saw this happen at our Marina the pump out station collapsed a metal tank on a houseboat. To much suction and not getting enough air, inexperienced dock hand. They now gradually open the pumpout hose this seemed to correct the problem after they had to pay for a new tank in the houseboat.

[Capt Ron]

Steve,
You are experiencing the same issue. The vacuum flush systems only have that little 5/8 opening to keep up with the vacuum. The fact that the waste re-entered your boat proves we dealing with the same issue. Pump style of toilets will break the vacuum automatically when they are empty. You will hear them howl. Not the case for vacuum flush systems. I think Rinker should put a vacuum break valve to assist in the venting during pump out.

Steve, I would definitely get your dealer involved now... don't wait until your boat is out of warranty, secondly, you don't want that mess in your bilge ever..! Both our boats are new and now is the time to bring this to their attention. PM me if you want my assistance. I'm sure there many boats out there that are vacuum flush and their owners never knew they had a problem. Who checks the tanks after a pump out..? They will eventually go back to almost their original shape, however, no tank will take that abuse for long.
Cheers,
Ron

[Tony Walker]

You all peaked my interest.

Anyone know how to get a look at the waste tank on a 2006 342?

I am sure it is under the aft bunk but I have periodically had all of the mattreses off of there and I can see the bilge pump and the sump for the shower but nothing else.

I have the vacuflush so I am concerned about this same issue.

Tony
Salt Shaker 342

[Black_Diamond]

The waste tank on the 342, unless they moved it from my 2003 year, is next to the port fuel tank.  About the only way to get at it is under the port cockpit cushion seating.  If you empty out the storage, you should see an 8" diameter deckplate that unscrews.  One you take it out, a flashlight will let you see it all.  You can get the sending unit out that way too.

Takes a bit of twisting and crawling, but it is a boat!

[Tony Walker]

Thank you Black_D

I have wondered what was underneath that inspection hatch for a while.

Once I attempted to get inside the compartment to see but I soon realized that if I did make it into the compartment, it would take the fire department to get me out!

I have noticed that most boat mechanics are smaller and more flexible than I am  

Tony
Salt Shaker 342

[Craig]

I would try putting a none collapsable vent hose on the vent. When I first got my boat it had that same hose with the blue stripe. Not the right stuff.Mine would collapse when I pumped the tank, restricting the air. Athough not as bad as yours. But I do not have a vacuflush.

[Capt Ron]

Thanks Craig, I will open the hatch next time I pump out and see if that hose will collapse. However, I still think there is a problem with such a small vent when there is no other way to vent the tank.
Cheers,
Ron

[statbiomed]

Do you have a filter on the vent ?. could it be clogged ? Also check the vent outlet nipple on the top of the tank. The hose may be clear and the nipple clogged. Also do you have a y valve and macerator. Is the valve in the correct position ?
Our 320 has an electric head. No pump out problems

[Rinker342]

Thanks for the info on seeing the 342 holding tank.  I have never been able to view mine on my 2005, and have sometimes had the opposite problem of not getting a complete pump out.  I think our local pump out station had a problem last year that has been fixed.  I guess I better get into that deck plate and take a look.  Ron's right.... you NEVER want that stuff in your bilge.  I'm also passing this along to others I know that don't frequent the forum.  Thanks for some great info!!

[Banker's Hours]

Another way to look at those tanks (water and waste) on a 342 is to open the mirror over the midberth, unscrew the side panals and have a look; waste was the port side on my old 2002 342. I have put a heater in this area in winter to keep the water from freezing, you can't get to them from the engine room.

Wayne 350 EC
Banker's Hours
Kentucky Lake

[Capt Ron]

Hey Craig thanks, I checked my vent tubing and it was just a water hose. This hose would definitely collapse under any type of vacuum. I would suggest to everyone to check this when doing maintenance. Can't believe this one slipped by their QA.

Steve, check your boat. I bet you have the same problem. The hose should say VAC on the side of it. If it is a plastic hose with a blue strip on it, that's your problem.

I'm going to watch the next pump out to see if the tank has a weak spot now. If it does Rinker, will be hearing from me. I wouldn't wish a tank explosion from that tank into the bilge.

Cheers,
Ron

[Black_Diamond]

good thought on the vent hose if it's set for vacuum.  I'll have to check mine now!

[cyber]

check out the relief valve here...

http://www.environmentalmarine.com/accessories.html

Also - the pumpout adapter...