Horrible smell found, now how to keep it away.

[GILow]

Hello cruisers,

For the last six months, I have been trying to track down an utterly horrible smell, a bit like the worst sandshoes you have ever met, combined with a blocked sewer. After scrubbing every bit of the bilge I could find I ended up with spotless bilges, but the stink remained.

Anyway, turns out all along the problem was with one of two keel tanks about a quarter full of old water. When I pumped it out it was so foul that it was actually fizzing as it came out of the hose.

The problem I now face is as follows:

The tanks are isolated from the main water system as the plumbing to that bit of the boat needs a lot of work. As it is I have over 300 litres available from the main tank, so the two keel tanks are not really needed as long as the boat continues to be used as a weekender as it will for the next few years at least.

Although I can flush the tanks with fresh water, I can't get the tanks bone dry as the pickups are stuffed, so there will be some quantity of water that I can't get out, so the smell will probably return.

The plan to revamp that bit of the boat plumbing really needs the engine out and goodness knows what else, so I am looking for a way to stop the tanks becoming foul again.

Can anyone suggest an additive or method that could be used to treat the tanks for the interim, even if it is something I need to replace at regular intervals.

Matt

[Rakuflames]

Originally Posted by GILow

Hello cruisers,

For the last six months, I have been trying to track down an utterly horrible smell, a bit like the worst sandshoes you have ever met, combined with a blocked sewer. After scrubbing every bit of the bilge I could find I ended up with spotless bilges, but the stink remained.

Anyway, turns out all along the problem was with one of two keel tanks about a quarter full of old water. When I pumped it out it was so foul that it was actually fizzing as it came out of the hose.

The problem I now face is as follows:

The tanks are isolated from the main water system as the plumbing to that bit of the boat needs a lot of work. As it is I have over 300 litres available from the main tank, so the two keel tanks are not really needed as long as the boat continues to be used as a weekender as it will for the next few years at least.

Although I can flush the tanks with fresh water, I can't get the tanks bone dry as the pickups are stuffed, so there will be some quantity of water that I can't get out, so the smell will probably return.

The plan to revamp that bit of the boat plumbing really needs the engine out and goodness knows what else, so I am looking for a way to stop the tanks becoming foul again.

Can anyone suggest an additive or method that could be used to treat the tanks for the interim, even if it is something I need to replace at regular intervals.

Matt

Add about 1/4 cup bleach to every 10 gallons of water in the tank. Fill it up about 9/10 of the way. Take the boat out and slosh it out around real good.

Drain the tank completely.

Do this as often as you can.

Don't drink that water, and in fact, if you use it to wash your dishes, you should rinse them with bottled or hose water, not water from the tank. Personally I would never trust it again. If you ever read a microbiology textbook you will come to the same conclusion. It is NOT POSSIBLE to sterilize anything, even the finest stainless steel surgical instruments, 100%. Critters continue to lurk in tiny imperfections of the surface.

However, if there are any hoses or anything else regarding the water tank you can replace, I would replace them since it's become so contaminated.

Once you have it rosy again, you can use a much smaller amount of bleach to keep the water smelling sweet, but I would add a little extra bleach to your dish water, just as restaurants are required to do. Then you rinse them with regular tap water, which you can get from a hose. Traveling, you'd be better off rinsing them in salt water and then wiping the salt off afterwards than your tank water (unless you're in a harbor, or marina, or some place else with lots of boats and inadequate water solution, because not everyone uses the head).


PS I've had this problem. I'm not just making all this up or guessing.

[boatman61]

As Raku says... only I'd just use 1/4 cup of plain bleach per tank your not using then top up... leave it a month, drain and repeat.
Once you've got the tank back on line to use.. it should be smelling good by then.. add 1 capful of bleach/ 10gals... if you intend it for consumption... else you'll rot your guts with 1/4 cup a time...
1 cup of bleach in a 40gal tank will have you in hospital sooner or later.... as many UK pensioners found when they used a mild bleach mix to soak their teeth overnight instead of just water... bleach is hard to shift and you'll soon have a build up in your tanks.

[senormechanico]

I would immediately stop everything in my life and yank the tank(s), but that's just me.

[Rakuflames]

Originally Posted by boatman61

As Raku says... only I'd just use 1/4 cup of plain bleach per tank your not using then top up... leave it a month, drain and repeat.
Once you've got the tank back on line to use.. it should be smelling good by then.. add 1 capful of bleach/ 10gals... if you intend it for consumption... else you'll rot your guts with 1/4 cup a time...
1 cup of bleach in a 40gal tank will have you in hospital sooner or later.... as many UK pensioners found when they used a mild bleach mix to soak their teeth overnight instead of just water... bleach is hard to shift and you'll soon have a build up in your tanks.

Well, I wouldn't wat a month. That's where we disagree, because you want that tank functional. Bleach works to kill stuff very fast. You can fill the tank with heaveily chlorinated water a couple of times a day doing this. But I would sail the boat inbetween so the bleach shlowshes around into every corner. That's why you don't quite top it off -- so it has a little room to move around. If you wait a month between treatments, that's five months before you have it cleaned up.

*Once it's clear,* yes, one capful for 10 gal is enough, but really hit it harder at first.

I NEVER said to DRINK the heavily chlorinated water. You use it as the cleaning agent.

I would do the 1/4 cup per gallon five times, fairly rapidly -- five times drained and refilled within a couple of days.

You wouldn't drink that any more than you drnink the water you use to clean a kitchen floor.

[Stu Jackson]

Fresh Water System Recommissioning 101 hot water "rotten egg" odor

[GILow]

Originally Posted by senormechanico

I would immediately stop everything in my life and yank the tank(s), but that's just me.

Now that's what I WANT to do, alas I have to concede that finishing the house first is a priority.

[GILow]

Originally Posted by Stu Jackson

Fresh Water System Recommissioning 101 hot water "rotten egg" odor

Thank you, that's an excellent thread. I missed it my searching, not sure how, but in fairness I would not have described the smell as "rotten egg" which to me is Hydrogen Sulphide gas. Seriously, my tank smells worse than that! Anyway, the thread covers the issue very well, so thanks for the pointer.

Matt

[GILow]

Originally Posted by Rakuflames

Well, I wouldn't wat a month. That's where we disagree, because you want that tank functional. Bleach works to kill stuff very fast. You can fill the tank with heaveily chlorinated water a couple of times a day doing this. But I would sail the boat inbetween so the bleach shlowshes around into every corner. That's why you don't quite top it off -- so it has a little room to move around. If you wait a month between treatments, that's five months before you have it cleaned up.

*Once it's clear,* yes, one capful for 10 gal is enough, but really hit it harder at first.

I NEVER said to DRINK the heavily chlorinated water. You use it as the cleaning agent.

I would do the 1/4 cup per gallon five times, fairly rapidly -- five times drained and refilled within a couple of days.

You wouldn't drink that any more than you drnink the water you use to clean a kitchen floor.

Yes, I understand the point here and I won't be drinking from or even connecting to these tanks.

Just to clarify, I am planning to leave the tanks unused for at least three to five years, so the higher concentration of bleach is to prevent the smell from coming back in the interim. LATER, I will either pull the tanks completely, or dabble with reinstating them if needed. The problem is I am using a boat that was long ago VERY well set up for serious blue water cruising as a day/weekend boat, and there just is not the time to fix some of these more complex systems the way they should be done.

Our plan is to see if we want to do longer distance stuff in about three to five years so I don't want to ruin anything on the boat through neglect between now and when I come to recommission things.

[boatman61]

Originally Posted by GILow

Thank you, that's an excellent thread. I missed it my searching, not sure how, but in fairness I would not have described the smell as "rotten egg" which to me is Hydrogen Sulphide gas. Seriously, my tank smells worse than that! Anyway, the thread covers the issue very well, so thanks for the pointer.

Matt

LOL... you should try showering in motels in NY State... serious bad eggs... and the Pamlico area you can smell the bracken... with your tap water services its no wonder you folk only drink bottled water..

[GILow]

Originally Posted by Stu Jackson

Fresh Water System Recommissioning 101 hot water "rotten egg" odor

Oh, now I get it, different forum. I could not work out how I missed that thread, but I assumed it was on CF.

Are Swanson owners allowed to look at Catalina forums...?

[GILow]

Originally Posted by boatman61

LOL... you should try showering in motels in NY State... serious bad eggs... and the Pamlico area you can smell the bracken... with your tap water services its no wonder you folk only drink bottled water..

You get used to it. When we first came to Adelaide we could not stand the water, now it tastes normal to us, and the water in Melbourne, where I grew up, tastes really strange.

Takes about three years to adjust.

Funnily enough the foul water in the tanks came all the way from Melbourne too....

[Dulcesuenos]

We had old nasty water that had sat for 1.5 years in our system. I read an article on using hydrogen peroxide. Think we used half a pint for 66 gallons. let it sit for a few hours with partially full tanks then pumped most out and refilled. Nasty eggy sulfur smell never returned.

[GILow]

Originally Posted by Dulcesuenos

We had old nasty water that had sat for 1.5 years in our system. I read an article on using hydrogen peroxide. Think we used half a pint for 66 gallons. let it sit for a few hours with partially full tanks then pumped most out and refilled. Nasty eggy sulfur smell never returned.

Thank you, I'll add that to the list of options. Have done the flush and bleach thing this morning, giving it a few hours now, will go back this arvo and see/smell how it is going.

Quite a pong!

[Rakuflames]

Originally Posted by GILow

Yes, I understand the point here and I won't be drinking from or even connecting to these tanks.

Just to clarify, I am planning to leave the tanks unused for at least three to five years, so the higher concentration of bleach is to prevent the smell from coming back in the interim. LATER, I will either pull the tanks completely, or dabble with reinstating them if needed. The problem is I am using a boat that was long ago VERY well set up for serious blue water cruising as a day/weekend boat, and there just is not the time to fix some of these more complex systems the way they should be done.

Our plan is to see if we want to do longer distance stuff in about three to five years so I don't want to ruin anything on the boat through neglect between now and when I come to recommission things.

The thing is to do it multiple times with an overload of bleach.Shock it, drain the tank, repeatedly. It's really impossible to sterilize anything completely but multiple times helps.

And of course, don't leave water in it, bleach or small amounts of bleach, for any length of time. If the boat is going to sit for 3 - 5 years, let it sit with a treated, dry tank.