Black tank vent line inspection and cleaning

Hi guys,
I suspect the sewage tank vent lines on my 45m yacht are partially clogged, the yacht was in a bad state of affair when I took her on. I have new replacement VOF filters but would like to inspect the lines before I fit them. I have attempted the following:

  1. Endoscope inspection using cheap 100’ ‘Amazon’ endoscope - problem is there are quite a few bends and valves to negotiate and I only managed 10’ or so before I could inspect no more
  2. Local pipe inspection companies are not interested due to liability insurance issues working on yachts
  3. Sourcing pro pipework endoscope - the camera is too large to negotiate the bends

Vent line specs: 100’ approx run, 2" pipework with many turns

Any help?

You say this is a tank vent. There should be no valves in it. Same same with “many bends” should be as few as possible, no traps (low points) sloped toward tank at all times. But if wishes and buts were candy and nuts, everyday would be Christmas. Is it just a tank vent or a stack vent for the sewage drain piping as well? That would effect what you do about it. If truly a tank vent only I would expect most solids to have accumulated near the tank connection. Is there a mechanical joint there where you can inspect? 100 feet of 2 inch pipe is not much of a vent, then again I have no idea about yacht systems. Area of vent should exceed area of lines flowing in. Good luck but the endoscopy seems a bit much as first response.

[QUOTE=Mac Macdonald;194613]Hi guys,
I suspect the sewage tank vent lines on my 45m yacht are partially clogged, the yacht was in a bad state of affair when I took her on. I have new replacement VOF filters but would like to inspect the lines before I fit them. I have attempted the following:

  1. Endoscope inspection using cheap 100’ ‘Amazon’ endoscope - problem is there are quite a few bends and valves to negotiate and I only managed 10’ or so before I could inspect no more
  2. Local pipe inspection companies are not interested due to liability insurance issues working on yachts
  3. Sourcing pro pipework endoscope - the camera is too large to negotiate the bends

Vent line specs: 100’ approx run, 2" pipework with many turns

Any help?[/QUOTE]

Cut and remove section of the pipe where convenient and keep inspecting. Replace removed section afterwards using Straub couplings.

Unscrew masthead light cover, slide old boat out of the way. Then slide in new boat with new black water piping and replace masthead light cover.

[QUOTE=Fraqrat;194625]Unscrew masthead light cover, slide old boat out of the way. Then slide in new boat with new black water piping and replace masthead light cover.[/QUOTE]

that is going to be difficult without a levitation system to support the light cover however DARPA has been working on this very problem and with a $750M budget has developed a dynamically positioned blimp which can hover in exact position while the new blackwater piping equipped new vessel is moved into place.

Here is a photo of the prototype blimp showing the special mastlight holding fixture beneath it. Details on the blimp and the holding structure are classified and only available on Wikileaks

It is reported the Norwegians are looking to use this system to rebuild old Turdwater OSVs into gigantic brand new factory trawlers with US fisheries endorsements. Here is a photo of their version

[QUOTE=Mac Macdonald;194613]Hi guys,
I suspect the sewage tank vent lines on my 45m yacht are partially clogged, the yacht was in a bad state of affair when I took her on. I have new replacement VOF filters but would like to inspect the lines before I fit them.
Any help?[/QUOTE]

Doesn’t this stuff work?

if that doesn’t work, maybe you can try some of this

jeez, some of you guys are cuel!, and C capt., gawd!!. OK McDonald, It sounds like it’s time for the nuclear option. hook up your firehose to the vent discharge end and let’er rip. You may find this vent line has a couple other lines goin into it but the fire hose will show you where they are. make sure you have a tank top cracked or something so you don’t over pressure the tank! it may get messy somewhere but it’ll be a hell of a lot easier than trying to dissect 100 ft. of pipe.
now then: how can a 150 ft. boat have 100 ft. of vent pipe? KP chief is right, it should be a straight vertical shot. These vent lines all clog given enough time. Your biggest challenge is going to be getting a good fit on the hose to the disch. end of the vent, and yes, you can do it on the tank side but you’ll have to do some serious plumbing first. let us know how it goes. at least a 2" line will have some velocity to it, some of that ‘stuff’ is pretty hard!

1 Like

and if you actually find a valve on a b/w vent line, educate us!

[QUOTE=Mac Macdonald;194613]

Vent line specs: 100’ approx run, 2" pipework with many turns

[/QUOTE]

Is this an Italian built boat? Benetti? It isn’t that difficult to trace the piping, you just are going to have to bite the bullet and start removing overhead panels and get to work on it.

The valve thing seems a bit bizarre, there is no reason to have a valve on a black tank vent. What makes you think the vent line is “partially blocked” anyway?

If the black water system is screwed up so badly the vent is blocked from overflowing and a really bad design maybe it is time to completely clean the tank and fill the vent line with “Drano” or equivalent and let it soak. You shouldn’t have a filter on the vent line anyway but if you really want an odor filter then this is a good time to remove the stupidly long vent and replace it with a short (mostly) vertical run to someplace where an effective odor filter can be placed and easily maintained.

as mentioned, if you actually find a ‘valve’ on this vent line then it’s prob not the vent line but let us know. If it has a valve, then shut it and fill this clogged line with a cleaner to soak as it won’t take too many gallons (diluted)… another option!!! Steamer has viable option there.