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Boat Stink: The tale as old as time

Posted: January 28th, 2025, 1:24 am
by Alastair MacGregor
So, since we took ownership of our 1999 445 (Diesel) we have had some Stink issues in both head areas and under the galley sink. We removed and cleaned both commodes (Muriatic acid needed to remove years of scale). Rebuilt both Vacu-flush pumps and replaced duck-bills. Also replaced the line from Aft head to grey water holding tank. The heads are now stink free but we cannot get the smell out of the cabinets area under the galley sinks. The sink plumbing is there but also the Vacuum pump for the Fwd head. Any ideas what could be the source of the odor? Frightened that it may be the line from the pump to the grey water holding tank for the Fwd head.....Help

Re: Boat Stink: The tale as old as time

Posted: January 28th, 2025, 10:01 am
by Carverlvr2
Like you, I have vowed my new boat will be odor free and in my countless hours of research and conversations, one product/solution keeps popping up…Noflex. It’s a digester you add to your holding tank and toilets and it not only eats away at the built up sludge that’s likely coating your hoses and tank and causing the permeation odors, it also naturally releases odor-free gasses instead of the stinky ones we’re all familiar with. Part 2 of your solution is that everyone also recommends putting some of the same Noflex product down your sink drain and into your sump boxes as they can be a source of super stink as well. Thinking you may have both issues in the same areas. I ordered a couple bottles from MarineSan and looking forward to implementing as the weather warms here. Hope this helps. Good luck on your quest!

Re: Boat Stink: The tale as old as time

Posted: January 28th, 2025, 10:43 am
by bud37
Alastair MacGregor wrote:Source of the post Frightened that it may be the line from the pump to the grey water holding tank for the Fwd head


If you want to check waste lines for permeation a good test is to take a warm damp rag and wrap it round the hose in question , leave for awhile then take it outside and sniff, you will know. Good luck man.


Oh to add , once the hoses are permeated my understanding is there is nothing that can save them other than new hoses unfortunately.

Re: Boat Stink: The tale as old as time

Posted: January 28th, 2025, 1:19 pm
by buster53
Just an FYI, you mentioned gray water tanks a couple of times. Gray water is discharge from sinks and showers…black water is discharge from heads. The two should never come in contact with the other.

Re: Boat Stink: The tale as old as time

Posted: January 28th, 2025, 1:41 pm
by Carverlvr2
Bud37 makes a good point about the hoses and permeation but I’ll add that quite a few users of Noflex also dissolved some in a spray bottle and litterally sprayed the crap out of their sanitation hoses. That on top of cleaning out and deodorizing the hoses from the inside greatly reduced or even eliminated their smells…at least buying some more time before the inevitable. Again, this is only what I’ve read but it’s the same reports across multiple forums and users. Hoping for the same results on mine soon.

Re: Boat Stink: The tale as old as time

Posted: January 29th, 2025, 10:30 am
by bud37
I have tried that stuff, expensive and for me, did not notice much of anything, certainly didn't clean up the tank.Let us know if it works for you.

See the thing is, you really have no idea what someone before has added to that system or how long it was left untreated, could have already damaged the inside of lines. You could spend months trying this or that or a couple hours and just replace the lines with new and have done with it. I know sometimes it is difficult to do but when it is done.....nice !

Pump out suction hose ...Tip.....because waste sits in that line as the tank fills it makes that section of hose particularly bad, put PVC pipe the last couple feet to the tank where the pump out waste hose attaches to the tank if your tank is evacuated from the bottom side. Better ones have fittings that go thru the top, they are ok.

Re: Boat Stink: The tale as old as time

Posted: January 29th, 2025, 7:13 pm
by Alanna Mo Cree
We use Noflex Digestor too. It is pricey, but a tablespoon left in the head will make the bowl clean as new with no work. I leave a tablespoon in the head when we leave and then it gets flushed down on first use when we return. It took quite a bit at first using a tablespoon per person per day (or maybe two days), but once established it only takes about a tablespoon every few weeks. The holding tank monitor even started working again.

Re: Boat Stink: The tale as old as time

Posted: January 30th, 2025, 12:41 pm
by Alastair MacGregor
buster53 wrote:Source of the post Just an FYI, you mentioned gray water tanks a couple of times. Gray water is discharge from sinks and showers…black water is discharge from heads. The two should never come in contact with the other.

Sorry, black water tank. the smelly one

Re: Boat Stink: The tale as old as time

Posted: January 30th, 2025, 12:42 pm
by Alastair MacGregor
bud37 wrote:Source of the post I have tried that stuff, expensive and for me, did not notice much of anything, certainly didn't clean up the tank.Let us know if it works for you.

See the thing is, you really have no idea what someone before has added to that system or how long it was left untreated, could have already damaged the inside of lines. You could spend months trying this or that or a couple hours and just replace the lines with new and have done with it. I know sometimes it is difficult to do but when it is done.....nice !

Pump out suction hose ...Tip.....because waste sits in that line as the tank fills it makes that section of hose particularly bad, put PVC pipe the last couple feet to the tank where the pump out waste hose attaches to the tank if your tank is evacuated from the bottom side. Better ones have fittings that go thru the top, they are ok.


Thanks, much appreciated

Re: Boat Stink: The tale as old as time

Posted: January 30th, 2025, 12:43 pm
by Alastair MacGregor
Thanks, much appreciated