Fuel noticed in water after first fueling: source?

[Geronimosails]

Hi all,
Thanks in advance for helping this newbie 1990 Hunter 30 owner.
I have motored/sailed about 5 times with this newly purchased boat. This past weekend the diesel tank read half full with the same gas it had in it when purchased. I decided to top off the tank and really track fuel comsumption and the accuracy of the gas gauge.
Having filled it very full, (ran out the top) I motored 15 min back to dock. There I discovered a gas slick behind the boat after turning off the engine. It disappeared after several minutes at dock. No visible leaks inside the holds, bilge, etc. This is my question: is there an overflow valve causing this, or do I have a problem? Since owning the boat this has never happened before during or after motoring. Thoughts? It's has a Yanmar engine, if that helps. Thanks much for any advice!

 

[spraygun]

Hi all,
Thanks in advance for helping this newbie 1990 Hunter 30 owner.
I have motored/sailed about 5 times with this newly purchased boat. This past weekend the diesel tank read half full with the same gas it had in it when purchased. I decided to top off the tank and really track fuel comsumption and the accuracy of the gas gauge.
Having filled it very full, (ran out the top) I motored 15 min back to dock. There I discovered a gas slick behind the boat after turning off the engine. It disappeared after several minutes at dock. No visible leaks inside the holds, bilge, etc. This is my question: is there an overflow valve causing this, or do I have a problem? Since owning the boat this has never happened before during or after motoring. Thoughts? It's has a Yanmar engine, if that helps. Thanks much for any advice!

Yes there is a vent somewhere.You should see a big red oily streak where it was pouring out.I don't even know how you were able to overfill that bad at a fuel dock.Unless you did it at a marina.Releasing that much fuel can result in a huge fine.Most marinas don't want people filling their boats at the marina,just for that reason. Don't overfill.

 

[Benny17441]

The fuel tank has a vent outlet likely located back at the transom. Spilling fuel in our waterways is a serious offense which could cost thousands of dollars in fines. In some States the Marina workers are compelled to report anyone that spills fuel. Having given you the warning when refueling you need to be very careful and slow down the flow as soon as you sense air coming out of the fill tube. Do not try to fill it to the top like you would in a car or fuel will come out the vent. There is whistle that you can install in the vent hose and as the tank fills up you will hear the whistle. I personally do not use it but somebody will chime in and give you the name or you can look for it in the archives. Make sure you have insurance and that it covers accidental spills as otherwise it could get real costly.

 

[Geronimosails]

Thanks for your advice, and yes, I did notice in the back transom a pink streak while sitting at the fuel dock. We hosed it off before departing; had thought it had just run down from where the nozzle was inserted into the tank. The fuel dock was 15 min motor from my marina, but hopefully the vent you mentioned was the source of the spill after I returned to my dock. I'll watch it next time. Learning curves, geez...it's why we drink, isn't it? Lol thanks again!

 

[Geronimosails]

Benny, thanks for your quick advice. I did try to fill it as I do the car, and obviously that was not a good idea!! Thankfully the spill wasn't really excessive, maybe a couple of feet max, but enough to scare me into investigation. It disappeared quickly, so hopefully, no big harm done. I am grateful for the whistle info; will ask around about that. Best wishes and thanks again!

 

[Saillife]

One thing you should do when refueling is to keep an oil absorbent pad handy for any spill.


It's good you're checking your fuel consumption. Also keep an eye on how your fuel gauge works. They can be very inaccurate. On my boat the difference between 3/4 and full is only ~2 gallons (on a 20 gallon tank).

Brian

 

[Geronimosails]

Thanks Saillife for your advice, and will take it to heart. Kinda interesting about your tank reading, too, but good that you at least discovered it before running it dry. Best wishes and thanks again!