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Fuel is in waste holding tank what to do ?

Jan 24, 2017
549
Hunter 34 Toms River Nj
so my fellow power boat neighbor fist time boater went to the fuel dock with his girlfriend to fuel up and his girlfriend accidentally opened the wrong cap and the dock attendant started to fill his waste holding tank with gas! Approximately 15 gallons before he realized what happened. After returning to the dock we had a oil tank recovery company come out and pumped out all of the fuel from the holding tank. When we saw wast being pumped from the tank we believe that 95% of the gas is now removed.
Still smell gas, so we went to automotive store and added a gallon of gunk degreaser flushed tank with water eight times with oil recovery company, much better than before however still smells like gasoline.
Added a gallon of dawn dish detergent as soapy water and filled the tank with fresh water all the way to the top until it came out of the over flow. I told him to leave it full and let the yard manager know what happened so they can watch the boat.
Filled the tank with soapy water for two reasons. First to eliminate any room for gas fumes to accumulate and second to dissolve and gas that may be in the waste tank. Our hope is to pump out a few more times and be done

what do you all suggest other then replace the entire waste system which would be a huge under taking and expensive job. Any products or suggestions would be greatly appreciated
 
Oct 24, 2010
2,390
Hunter 30 Everett, WA
With that much washing and rinsing there can't be very much volume there. I would just use it normally and see if the odor fades away. You might also do the Peggy test, (take a rag and rub it on the sanitary hoses, And then take the rag away and see if it smells of gasoline.) If it does you get to replace all of the hoses but I would be surprised if you had to replace the tank.
 
Dec 28, 2015
1,347
Laser, Hunter H30 Cherubini Tacoma
The possibility of flammable gasoline vapor in the system is minimal compared to the methane from the septic that will be in there also.
 
Jan 11, 2014
7,738
Sabre 362 113 Fair Haven, NY
I was recently at an unnamed boat yard where a 48' power boat was on the hard because the paid licensed captain had filled the water tank with diesel and the diesel tank with water. The lawyers are having a field day arguing about which insurance company, if any, is going to pay for the damages which are quite substantial.

Your friend should know and rest assured that this error is common and even the pros screw up. I wouldn't worry too much about the remaining odor give some time and continued use. If by this time next year it still smells, then it might be time to start replacing things, like the tank.
 
Jan 1, 2006
5,989
Slickcraft 26 Greenport, NY
I inadvertently put water in my fuel tank ... dumb....dumb...dumb. Since the gas floated on the water it was relatively easy to suck the water out with a hand operated pump (Designed to remove oil from the crankcase). When I started getting gas in the water I knew it was time to stop. The engine was a bit pissy for a while, but we got through it.
The reason I screwed up is that I would dock either bow in or stern in depending on the circumstances. I just got mixed up on which side was water and which was fuel.
 
Jul 20, 2020
19
Hunter 30 1001 Nyack NY Hudson River
Get a water cap the says "water" on it, I'm sure there is a fuel cap that says "diesel fuel" on it, or "Gas" if that is the case
 
Jan 18, 2016
664
Catalina 387 Dana Point
Get a water cap the says "water" on it, I'm sure there is a fuel cap that says "diesel fuel" on it, or "Gas" if that is the case
Never seen one that wasn't labelled. Old boat said "Gas" new boat says "Diesel"

For the O.P - I'm in agreement with the consensus of the thread - just use it. A lot. Sewage smells bad enough it will win eventually. Unless, the gas ended up eating away at bits of the system. Gas doesn't affect or permeate polyethylene so if the tank is made of that (likely) it should go away. The plumbing may be a different story: the "rag test" as mentioned above would be a good idea to check.
 
Apr 1, 2004
107
Catalina 34 Herring Bay Chesapeake, MD
It does happen, but not really a COMMON occurrence. If tank is anything but stainless it will need to be replaced, this includes any plumbing that was contaminated. No other way to totally remove all traces of fuel and smell.
 
Jan 11, 2014
7,738
Sabre 362 113 Fair Haven, NY
It does happen, but not really a COMMON occurrence. If tank is anything but stainless it will need to be replaced, this includes any plumbing that was contaminated. No other way to totally remove all traces of fuel and smell.
Holding tanks should not be stainless. The acidic contents of the tank will take their toll.
 
Nov 26, 2012
1,520
Hunter 34 Berkeley
I would try an industrial degreaser. I believe you can get them at Home Depot or maybe an auto parts store. Industrial degreaser is citrus based. It cuts the grease and it smells like oranges. Run that through a few times. Eventually it will smell better or you will have to replace the system.
 
Dec 2, 1997
8,089
- - LIttle Rock
Gas doesn't affect or permeate polyethylene so if the tank is made of that (likely) it should go away.
Sorry, NOT true! Yes, there are PE gas tanks, but they're not made made from same type of PE as water and waste tanks. Water and waste tanks are made using LINEAR poly...petroleum products don't just permeate it, linear PE actually can actually "sweat" gas.

Plastic fuel tanks must be made using CROSS LINKED polyethylene, which has a completely different molecular structure...they must also meet very specific USCG standards including fittiings types and locations and not only wall thickness for the size of the tank, but can have no surface on which liquid can pool.


Get a water cap the says "water" on it, I'm sure there is a fuel cap that says "diesel fuel" on it, or "Gas" if that is the case
"Fuel," "water" and "waste" are usually etched into the fitting's flange, not the caps because caps are easily lost and replaced. However you can get color coded caps--blue for water, red for fuel, black for waste. If you can't find color coded caps, paint 'em yourself.

Btw, I once put about 35 gallons of water into the starboard gas tank on own boat. My husband was at the helm warming the engines to go out when he noticed the fuel gauge on that tank was suddenly a lot higher than the other one and yelled at me to "STOP!!" I made color coded caps using nail polish the next day.

--Peggie
 
Jan 18, 2016
664
Catalina 387 Dana Point
Sorry, NOT true! Yes, there are PE gas tanks, but they're not made made from same type of PE as water and waste tanks. Water and waste tanks are made using LINEAR poly...petroleum products don't just permeate it, linear PE actually can actually "sweat" gas.

Plastic fuel tanks must be made using CROSS LINKED polyethylene, which has a completely different molecular structure...they must also meet very specific USCG standards including fittiings types and locations and not only wall thickness for the size of the tank, but can have no surface on which liquid can pool.
I stand corrected.
 
Oct 29, 2016
1,769
Hunter 41 DS Port Huron
Holding tanks should not be stainless. The acidic contents of the tank will take their toll.
Actually it would not be the pH of the waste, it is actually bacterial microbes which will eat stainless steel, the microbes thrive in stagnant water, ergo the reason thru hulls are not stainless steel.
 
Jan 7, 2011
2,829
Oday 322 East Chicago, IN
Get a water cap the says "water" on it, I'm sure there is a fuel cap that says "diesel fuel" on it, or "Gas" if that is the case
And in addition to the labels, mine are color coded…black for waste, blue for water tanks, and red for diesel.

Greg
 
Jan 24, 2017
549
Hunter 34 Toms River Nj
up date, yard manager said unfortunately this is more common than people think.

Fortunately he reacted quickly and had pumped out an flushed system many times.
Plumbing side effected appears to be limited to pump out side only due to the sea water discharge valve is closed and sealed with zip tie and obviously the tank itself.
He remove a few samples of liquid remaining within the tank and appears to only have a slight trace of fuel remaining. Yard mechanic scrubbed inside of hoses with a brush and citrus cleaning solution and then made up socks filled with oil absorption granules and lowered a dozen or so of them into the tank with strings to retrieve them in a few days. So far everything seams to working out. Can’t really smell any gasoline odor anymore, just the cleaning products used. Yard mechanic said if any gasoline odor remaining by the weekend he will put a low pressure blower on the waste pump out fitting and run it for a few days until all fumes are gone. Mechanic said that the air flow will evaporate any residual fuel remaining in the tank. He said that the have done this in fuel tanks that had water contamination and it woks well. Final step if absolutely necessary they will have to install a clean out plate on top of the the tank and scrub it out. So far he is into this mistake for about $400 -$500. Not to bad considering the thousands it would have been if he had to replace everything.

thank you everyone for your suggestions.
 
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Dec 28, 2015
1,347
Laser, Hunter H30 Cherubini Tacoma
Gasoline has a flashpoint of -44f anything left after blowing the system out for 10 or so minutes after getting the liquid out is residue that no longer is a flammable issue. Again, the methane produced in the tank is going to produce much more flammable gas than any gasoline vapor when in use. Being that it is a very small space, the difference between the gasoline’s lower explosive limit of 1.4% and methane’s 5.4% is irrelevant. Long story short......you are good, stop throwing money at it.
 
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Ward H

.
Nov 7, 2011
3,093
Catalina 30 Mk II Barnegat, NJ
After returning to the dock we had a oil tank recovery company come out and pumped out all of the fuel from the holding tank.
So far he is into this mistake for about $400 -$500
Considering the oil tank recovery company's work and all the work the yard has done, I would have expected the costs to be much higher. Sounds like things are proceeding well.