Converted Water-Diesel Tank Reversal

[sy_gilana]

Friends have done exactly that on a T37, same boat, same solution.
Boat called "Blue Wind" Currentlly in Mexico Pacific side.
I have lost touch with them, but will try to get some info to you via PM

[RaymondR]

Good grief.

Every time you wash up the dinner dishes in a sink you do so to prevent the propagation of harmful bacteria which you may ingest causing health problems. It's not rocket science.

Diesel oil is a hydrocarbon. Hydrocarbons tend to low toxicity when the more volatile light ends have been processed out, mothers use baby oil on their little babies bottoms to prevent nappy burn without poisoning the little beggars (unfortunately in some cases when you view what they grow into) it's highly refined hydrocarbon oil. One of the old remedies for intestinal worms was a table spoon of kerosine occasionally and it does not have appeared to have resulted in serious health effects (to the human anyway I don't know how well the worms handled it)

The reason I suggested a caustic soda solution is that it is water soluble and tends to saponify oils and fats which tends to convert the oil from hydrophobic thereby making it easier to remove, it's how soaps are made, the caustic forms a molecule which is water soluble on one end and oil soluble on the other end.

Replacing a SS tank in a boat is a big and probably expensive job and if the tank can be fairly readily cleaned out and safely reused it's senseless to replace it.

[Sailshabby]

Try Ronco tanks in California. They have a zillion (okay, maybe just billions) of tank configurations that might fit inside yours. I realize there might be a shipping issue, but sometimes, we’ll…

[Fore and Aft]

There I was thinking that the Dugong lover had been out in the sun to long but it seems Diesel Oil poisoning is a thing. I was all for giving that tank two or three flushes and then "She'll be right mate". I wonder if Dugong oil is just as toxic?
Personally I wouldn't waste my time with a bladder, better of finding some plastic or stainless steel tanks that will fit.
Looking at the photo, taking that tank out gives you a chance to really clean and paint that bilge properly.
Cheers

https://www.dovemed.com/healthy-livi...oil-poisoning/

[sanibel sailor]

I bet I have ingested more from siphoning diesel by mouth than one would ever get from a well cleaned tank. Smell and taste might linger would be my concern. Charcoal filter would manage that.


Reinforces my perception about surveyors. Everyone says "get a survey before buying", but there are a lot of surveyors out there who are not up to the task. Finding a great surveyor is not easy. I don't know if it is carelessness, laziness, or just incompetence, but those three characteristics tend to go together. I have had more surveys that I consider substandard than high quality ones. FWIW, the SAMS certification process seems to be less rigorous than NAMS.



Rant over.

[LittleWing77]

Originally Posted by Manateeman

Under no circumstances should you drink, use for cooking, or even shower in water unless it’s been examined by a certified lab.

Diesel is nothing you want to fool with at any level in your drinking water. I’m not going to expand this post into the science of diesel contamination nor my professional credentials in food process engineering. If you cannot find people who truly know how to decontaminate your tank and test the water, do not try to do this yourself. Please.

+1

Mark is absolutely spot-on. Cannot believe the previous owners! If it were me, I would figure out which of the two steel tanks would be easiest to remove, remove that one, make its replacement your water tank, replace all the hoses, etc. and route your plumbing system to that one.

Other tank then would be diesel and you can use the best of all the diesel hoses and accessories from the two tanks and utilize for your fuel system. (Maybe this is a pie-in-the-sky, too-optimistic perspective, I mean, we don't actually know how old the boat is, how long it's been on the hard and/or whether any of the old diesel hoses and system accessories would even be salvageable. Plus hose runs... oh geez, this is making my head hurt!)

You can only do your best and take things step-by-step.

Very best of luck,
LittleWing77

[Manateeman]

Siphoning diesel by mouth is an extremely dangerous practice. The medical literature contains many cases of not just severe injury, but an occasional death.
Please, please do not do this.
Diesel fuel contains Toluene, Ethylbenzene, Xylenes and Benzene.
These chemicals have been proven to cause damage to the central nervous system (your brain) the liver and the kidneys.
The manatee crew would like to point to a review in the Journal of Comparitive Clinical Pathology wherein mice who drank water contaminated with diesel, showed significant decrease in packed cell volume, hemoglobin concentration,
red blood cell count and mean corpuscular hemaglobin. The poor things exhibited a change in gait. The report concluded diesel contamination...even at the lowest concentrations...is harmful. One gallon of diesel can contaminate one million gallons of water. If you can smell it in water, you are way over the reporting limit.
Contamination of groundwater by diesel in fracking is under review by the EPA.
There have been two cases when a relatively small diesel spill resulted in over 200,000 people having no drinking water. Diesel spills are very difficult to contain and bioremediation requires the removal of much more material and requires much more time than common oil spills.
During the cleanup of the Alaska spill, two nitrogen sources were tested. A French urea based and a slow release protein based which was one of my personal projects within a Norwegian corporation. Urea, like diesel, quickly moves down in the beach sand. Then the process almost stops as the limiting factor becomes oxygen. Slow release nitrogen works well on thicker oil. You can dig down just a foot in the sand near the Cape Cod Canal and smell diesel from a spill many, many years ago. It is very difficult and extremely expensive to bioremediate diesel spills. Please do everything you can on your vessel to contain any diesel and prevent it from discharge into the ocean. You can put a bio sock in your bilge.
A clean bilge prevents the small discharges of petroleum products which ends up in the ocean we all share. It’s the right thing to do.
This is not only an opinion of the manatee crew, it’s simply the science.
Happy trails to you.
Mark and his Manatee Crew and their buddy Dugongs down under.

[RaymondR]

Originally Posted by sanibel sailor

I bet I have ingested more from siphoning diesel by mouth than one would ever get from a well cleaned tank. Smell and taste might linger would be my concern. Charcoal filter would manage that.

Reinforces my perception about surveyors. Everyone says "get a survey before buying", but there are a lot of surveyors out there who are not up to the task. Finding a great surveyor is not easy. I don't know if it is carelessness, laziness, or just incompetence, but those three characteristics tend to go together. I have had more surveys that I consider substandard than high quality ones. FWIW, the SAMS certification process seems to be less rigorous than NAMS.

Rant over.

On the diesel issue. Balance and objectivity required not absolutism.

[malbert73]

I definitely favor replacing the tank with a plastic one like Ronco. But, cleaning it well and using it for washing etc (NOT drinking) may be ok since water tanks draw from the bottom and any residual diesel will float to top. But you’d need to access top of water level and siphon that layer out every time your tank gets near empty for a while until you are sure it’s all clean

[Erasmuss]

When Stainless Sheet Metal is being manipulated into a useful end product there's oil involved.

All stainless vessels built for Sanitary Service are cleaned and passivated after manufacturing for Sanitary Service Compliance.

Trisodium Phosphate or TSP which is an inexpensive cleaner / degreaser is commonly used with 300 Series Stainless Vessels.

I suggest you read up on the Cleaning Procedures for Sanitary Service and the Chemicals used to do so.

Ditch all hoses and valves and start new. The Hoses - if proper in the first place - were designed for Diesel Fuel ... Not Potable Water and the Valves are too difficult to Clean properly.

If the diesel fuel left any varnish components or Asphaltenes on the interior surfaces it may be advantageous to mechanically clean those surfaces with scotch bright depending on the amount of deposit.

Broom sticks and rags will only get you to a starting position for the restoration of your tank.

Again I suggest reading up on the commissioning of Stainless Vessels for Sanitary Service.

A Good Bore Scope will be very helpful.

Sincerely,
Erasmuss

[MaungaMoana]

Thank you all for the advice, it is greatly appreciated!

We have reached out to a few companies from each solution you have suggested to see pricing and feasibility with our current setup.

Will be removing all contaminated hoses shortly too so we can beging planning their replacement system.

Hoping to get a plan sorted soon once we hear back from them and what's available in the area.

[BrightSEALAB]

Remove and replace all gaskets and o-rings and spend a good long time with a hot pressure washer like a Steam Jenny or a Hotsy. Use a detergent like Simple green from time to time throughout the process.

It will be fine.

[timb7734]

Two years into a ten year affair with a trawler, a marina worker pumped 15 gallons of diesel into a water tank of mine. The marina hired a vac truck to clean the tank and drain it, we used a food grade degreaser/deodorizer made by Simple Green with several hot water flushes. Never had a problem after with taste or odor, but we did use faucet mounted filters for drinking water anyway. Much cheaper and more convenient than the radical tank replacement solutions, thus worth trying before that.

[john manning]

It may not be any help considering where you are but in New Zealand there are several bladder tank makers. The one I have used before is Flexi Tanks NZ.

If you are going to use a bladder tank I would suggest first looking for an alternative place to put it. Successfully getting them into an existing metal tank (without removing that tank) can be very difficult.

[MicHughV]

My though would tend to be to leave everything alone. You get an extra 100 gallons of fuel, not a bad thing and trying to change stuff comes with an armload of issues, as pointed in previous posts.

I'm sure there is space under the settee's, inside a locker, etc, where you could fit a bladder tank for water. Maybe several of them in different places, connected together. This way you'd be assured the water is not contaminated. If you have a water maker onboard, even better....then your bladder requirements could be reduced.

That's the avenue I'd go.....