Fuel tank vent

[Ned Ludd]

While crawling through the aft end of the boat checking hose clamps and the general condition of things I found a random hose end tucked under the muffler. After further investigation I discovered it is the fuel tank vent. I shoved it through the cowel vent on the stern and tied it off with a zip tie for the time being. There is no existing fitting for it so I assume it was vented through the cowl vents before they were replaced. What is the preferred vent location? The fuel fill is on the port side aft cockpit seat, I am thinking high up on the port side of the transom.

 

[centerline]

anywhere outside the hull is good. it should have a high loop in the inside to prevent any water from splash, spray, or temporary submersion from running down the hose and into the tank.... with the high loop the chances of keeping your fuel clean are much better because the water would have to get in the little fitting, then go UP the tube a ways before running down into the tank... a lot of fuel tanks are amidships and so the factory installed vent it right under the rail... not the preferred location in my opinion, but it seems to work ok if it has the high loop in the vent line before it attaches to the thruhull vent fitting....

 

[flagbag]

Good job Ned... Your proactive "crawling investigation" is an example for all to look for issues before they become problems. A fuel tank venting under a hot muffler could show itself only the way you found it - or in a more explosive way.. well done and thanks.

 

[Peggie Hall HeadMistress]

Be sure to use a "vent" thru-hull that's rated for a fuel vent.

 

[Gunni]

Moisture filter. Don't let the quoted price scare you, they are available for $100.
http://www.oceannavigator.com/November-December-2011/Scrubbing-water-from-diesel-fuel/

 

[Jim 5757]

+1 on the H2OUT moisture filter! Put one a few years ago. Awesome product.

 

[Ned Ludd]

Thanks for the Replies, I mostly posted this to point out that you should never trust anyone but yourself and to be vigilant. The boat in question is 40 years old an inboard gasoline A-4, could have ended badly.
What I find odd is there are no signs of an existing vent, not even clamp marks on the hose end. Another one of life's unsolved mysteries I guess.

 

[Peggie Hall HeadMistress]

All of my boats had gas engines, so I know a bit about safe operation. You didn't mention a blower in the engine compartment. There needs to be one. It should run at least 4 minutes before starting the engine and also AFTER, but never during, fueling. I was also taught to always raise the engine hatch and stick my head into engine compartment to sniff for gas fumes before starting the blower.

On power boats, there also has to be two louvered vents, one on each side of the boat, one has forward facing louvres and one has aft facing louvers. These provide passive ventilation while underway. I'm sure you need them, but not sure where they belong on a sailboat 'cuz you don't want heeling to put 'em under water. So I think it's time to invite Maine Sail into the discussion.

 

[Gunni]

An gasoline A-4 with a fuel tank that vents inside the boat?! Go play the lottery man, you are the luckiest dude in Oregon!

 

[Ned Ludd]

Peggie: Yes it has opposing vents & a bilge blower

Gunni: Fortunately for me the bilge crawl was the second thing I did, motor out and take a sail was the first...
AFTER running the blower for a good 15 min because the boat had been sitting