Pump out = crushed holding tank! OUCH!

[ImRich]

This last weekend I filled up on gas and took advantage of their 'free' pump out service.

I remember when the service dude removed the pump from my black water outlet hearing a distinct sucking sound that was a lot louder than normal, and I remembered thinking, wow they have a powerful pump!

Three days later I looked in my engine compartment to find that my black water tank had been sucked a bit too tight! LOL It was slightly (well more than slightly) crushed/colapsed. It was even out of place in it's mounts! It's still usable, but with a smaller volume than is used to be. I think the sucking sound was the excess vacuum in my tank being relieved a bit.

My black water tank looks like it's made of nylon or some other whiteish looking plastic material.

I think it's still water-proof (thank goodness)! I didn't see any obvious cracks or signs of a leak yet (but I haven't tried to fill it yet), I will test it with fresh water.

But this has me thinking that perhaps I have a blocked vent line? I inspected the vent line and did not see any kinks. I suppose I will have to remove the vent line and test it.

So what would cause this issue? Is the marina where I gassed up liable for this at all if I need a new tank? Probably not!

I have a Jabsco head with a locking handle. Am I supposed to 'unlock it' when having my tank pumped out to prevent this from occuring again, or is the vent line supposed to be able to handle this situation (if my vent line is ok)?

Should I try to backfill (with clean water) or pressurize the tank in an attempt to 'resize' it back to somewhat normal shape?

Looking for some advice, as I never had this happen before.

[shrew]

A pump out should not require that the handle be unlocked, set to dry vs. wet pump or that the seacock be opened or closed. I typically close the seacock prior to a pumpout, but then again, I close the seacock before I get underway, and I need to be underway to get to the gas dock anyway. The only thing I can think of would be a clogged vent line. I've never seen this happen, but have read that with vacuflush heads, you do need a crush prof holding tank. I would have expected that tank to stand up to it. I doubt the marina has any liability here, however I'm not a layer. For the couple of hundred bucks it costs to replace, i wouldn't bother with chasing the marina.

[Huddo007]

Any chance you could get a pic for us?, I am always worried about this and would like to see the extent of damaged caused

[ImRich]

Here is a picture, this is after I re positioned the tank into the holder at the bottom. It had lifted out of the holder too!

[shrew]

Where is your vent line? The picture almost makes it look like they mounted the holding tank on its side.

[pascavone]

i think we are not getting the full story..... perhaps a killer turd was the cause...?

[ImRich]

Originally Posted by shrew

Where is your vent line? The picture almost makes it look like they mounted the holding tank on its side.

The vent line is on the top left corner, you can't quite see it in this picture.

I checked the vent and the thru-hull fitting was a bit clogged. It looked like some old toilet paper or something was stuck in it, probably from a long time ago. I can't imagine allowing a tank to get that full!

I cleaned out the thru-hull and flushed it with water, and hopefully I won't have this happen again.

I"m still debating if I should attempt to fill the tank with water to see if it will help to get it back into proper shape. I'm not too sure I want to try to pressurize it, as if a line lets go it may spray a bunch of stuff around that I woulnd't want spread around!

[shrew]

You're going to have a hard time 'Pressurizing' it with a garden hose. I wouldn't bother.

[pascavone]

my massarator line was full of dried petrified toilet paper at as hard as a rock.

I would fill your tank and pump it out, a few times, because the plastic get fatigued and will start with a dripping, with the boat rolling.

this could be the only fold in the tank you can see.... what about the other side?

water is 8 lbs a gallon, X 15 gallons = 120 lbs. against that tank wall.

The real problem is a drip smells just as bad as having the tank wide open.

lot of guys try calk, but in the hot sun that still ferments and expanse.

I pulled my tank and had a flange plastic welded for $100.

why get caught with it next season?

[Chesapeake Marc]

I am having the opposite problem right now. On my 3000scr the vacuflush pump keeps running after you flush the toilet and won't turn off. This in turn inflates the holding tank until it bows outward and pops up the board/cushion for the seats in the mid-cabin. I replaced the duck-bill valves, and was thinking about replacing the switch next however the more I think about it the tank appears to not be venting at all! I figure I will take of that issue first, but anybody have any experience clearing this line on a 3000scr?

[shrew]

Hi Chesapeake MArc, Welcome Aboard!!! did yo uupgrade to a vaccuflush head (Or did the previous owner) or did this come from the factory. Vacu-flush heads require a crush proof holding tank, which most newer ones should be anyway. This certainly sounds like a blocked vent line. There should be no way that the head is pressurizing the tank so much that it is distorting if there is a vent to alow air to escape. Are you sure the vent line isn't blocked?

Do you have an in line vent filter which might be full of fluid? I would still think enough air pressure should displace that as well. Through hull vent coquille corroded and blocked?

[Chesapeake Marc]

Just got the boat this spring, so not sure what previous owner did, I am pretty sure it is original. I was thinking filter as well or possibly the exiting coquille being plugged with something (bugs nest, crud, etc.). I am blocking off some time to track it down tomorrow, I was just wondering if anybody had found or changed out the filter and if so if they knew where it was and how to get to it? Any other tips for clearing the line would be helpful.

thanks!

[shrew]

An inline vent filter is not standard equipment, though some add it on to reduce head odor when flushing. Locate the holding tank. Locate teh tank vent line on the top of the holding tank (it will be near the top somewhere and will be a relatively narrow tube). Follow the vent line all the way to the through hull fitting. If there is an inline vent filter you will run into while following the path.