How to clean holding tank overflow on hull

[wgkenney]

Hi All,

I need some advice. I recently discovered that the pump out station we use "times out" after a certain amount of use. After taking longer than normal to pump out our first holding tank I only ended up pumping out half of the second sanitary tank (the pump timed out and I thought I was done). As a result my normal calculations for head usage were ... well ... a bit off. So we overflowed the forward sanitary through the vent. This resulted in a someone embarressing brown streak on my hull.

First, thanks to some other posts on this site I've found a few good tank level products and will look to install this winter so I can monitor both holding tank levels (and maybe the water tanks as well - They seem to be set to run out during my shower time).

Second, I've tried scrubbing this streak, used kitchen cleaners, non skid cleaners, and elbow grease. I've dulled it but it is still very visible.

Any thoughts on what I can use on this stain to get it off my hull.

Any help would be great!

Glenn

 

[Stu Jackson]

FSR, a gel oxylicitic acid

 

[Peggie Hall HeadMistress]

It's a VENT, not an overflow!

And the only thing that should ever pass through it is AIR! Allowing waste to spill out the vent is a sure way to block it...in fact, it maybe a blocked tank vent that's causing your pumpout to use extra time to pump out a tank and/or "time out" before it removes very much from the other tank.

A tank vent has two very important functions; 1. it provides an escape for air in the tank displaced by incoming contents. If air can't escape, the tank becomes pressurized, creating back pressure that makes the toilet harder and harder to pump and worse. 2. it provides a source of air to replace contents being pumped out of the tank. If there is no incoming air, the pumpout or macerator pump pulls a vacuum, preventing anything more from being pulled out. A particularly strong pumpout can even create enough suction to crack the tank.

So it's VERY important that the vent never becomes blocked. That means you have to flush it out every time you wash the boat and/or pump out the tank. But first, it may be necessary to scrape out the vent thru-hulls and the vent connections to your tanks.

As for your stain...Barkeepers Friend...whitewall tire cleaner...and there's a toilet bowl cleaner that's oxalic acid...I can't remember the name of it, but someone here will.

 

[Ralph Johnstone]

A Sure Fire Way ..................

............ of removing that stain is to use Meguiar's finest cut polish which is their Colour Restorer. You can rub all day without the worry of cutting through the gel coat and you are left with a high polish.

 

[wgkenney]

Re: A Sure Fire Way ..................

Thanks all. I odered products from West Marine last night and will take a shot at this stain this weekend.

One additional question. What is the easiest way to flush out the vent? I don't think it is clogged now but this sounds like some good preventive maintenence.

Glenn

 

[rgranger]

The brown color of fecal matter is the result of the breakdown of hemoglobin... which contains iron. So.... Stu is right on the money. Get some Oxalic acid.

 

[MitchM]

you will find that on most holding tanks, the vent on the outside of the hull attaches to a hose barb that is inboard. if the vent hose is truly clogged up at the vent port , you may find it easiest to simply replace the hose for a few bucks. look for the barb attachment on the inside of the hull opposite where the small metal vent is, follow that hose down to tank top. i had to replace mine when a wasp built a nest in the vent itself. used pipe cleaners and very small diameter plastic hose to poke the wasp stuff thru from the outside and try to clean the vent from the outside --thus pushing the wasp nest further into the vent hose. ended up removing the vent hose to clean it out and buying an extra length of vent hose to keep 'handy. ' i now keep pipe cleaners and a 2 ft length of very small diameter cheap clear plastic water hose on the boat, together with my extra vent hose ...as my 'vent cleaning ' kit...

 

[Peggie Hall HeadMistress]

Cancel the WM order and go to the hardware store!

You'll pay at least 50% less AND save the shipping cost!

99% of tank vent blockages are in the thru-hull and/or the connection to the tank...so it's VERY rare that it's necessary to replace the vent line. Removing hoses to scrape out the buildup of waste and the inevitable mud dauber nest in the spring is a pain. And if you replace the vent line every time it becomes blocked, one of these days you're gonna remove the hose when the tank is pressurized...and you're NOT gonna like what happens then!!

The simple solution is a new thru-hull that allows you put a hose nozzle against it and back flush it...not a "vent" thru-hull, but an open bulkhead or "mushroom" thru-hull. (see photo). If you'd been able to do that every time you wash the boat and/or pump out the tank--and actually did that!--you wouldn't have had a clog in the line you couldn't break up. Prevention is always easier than cure!

 

[wgkenney]

Re: Cancel the WM order and go to the hardware store!

Thanks all - I need to do some exploring on my tanks and connections (this is our first summer with this boat). As I recall the holding tanks are not readily accessable. I need to get my head in under the sink cabinent and try to trace the lines up and see what I can get to.

 

[wgkenney]

Since everyone was so nice to give me advice here I thought I would do an update for what ended up working.

First I tried the FSR. I applied with a brush on the stain and let stand about 3 min and rinsed. No effect. Repeated for 10 min with no effect and then I did it on a smaller portion and let stand 30 min with no effect. So for some reason it does not seem to work on this kind of stain; however, I used in on a few stubborn stains on my deck and it did a wonderful job removing those. So this was a good find for me.

I then used the 3M Marine Color Restorer and that did the trick. I had the boat back in the slip so just leaned over the side and got the upper half of the stain. Applied and used just some light to moderate elbow grease and the stain disappeared. I'm pulling the boat in about two weeks and will clean off the rest when it is out of the water.

Thanks again for all the help here.