Fuel venting question...

[Outnumbered]

Single 70 gal belly tank. My fuel vent is in the front of the tank and the filler, sender, and feed at the rear. My tank is full and the front of the boat is lower than the back while its in the garage.
If the air bubble in the tank is at the rear (filler, sender, feed fittings are not submerged) and the vent line fitting is submerged will this prevent the vent from relieving pressure? I am getting pressure at the filler cap that is not being relieved by the vent line. I checked the vent line for kinks but did not remove it to check for blockage.
I could jack the front of the boat up but its more stable down low while I'm working in it.
Thanks in advance.

[phebus]

If the pressure was great enough, it would force fuel out the vent. My guess is the pressure you get at the cap, is enough to compress the airspace, but not enough to force the fuel out the vent.
I wouldn't fill the tank that full, because if it does get hot enough to vent, fuel will puke all over the side of the boat, and on to the ground. If there was an ignition source in the area, it could get ugly (even though, by code, the garage itself should be vented)

[Outnumbered]

If the pressure was great enough, it would force fuel out the vent. My guess is the pressure you get at the cap, is enough to compress the airspace, but not enough to force the fuel out the vent.
I wouldn't fill the tank that full, because if it does get hot enough to vent, fuel will puke all over the side of the boat, and on to the ground. If there was an ignition source in the area, it could get ugly (even though, by code, the garage itself should be vented)
Thanks. I will be sure not to top it off next time. I just wanted to be sure that my vent is working OK.

[Boatcop]

Just keep the fuel cap slightly cracked. It will keep the fuel vented from the rear, the same as the regular vent.
Only do this if it's not puking gas from the cap.

[Moneypitt]

Is your water heater in the garage? If so, get that boat out of the garage, drain some fuel out so the vent can work properly. NO JOKE, you're dealing with a bomb, especially if the fuel is forced out the vent onto the floor while you're away from home, or worse, if you and your family are asleep in the house with an attached garage............MP

[Outnumbered]

Thanks. No worries on the fumes. Its not puking or fuming up the whole garage. I just changed the filler cap to a no-key style and was surprised that their was built-up pressure. The tank is not over filled its just on too much angle so I jacked up the front and will see how it goes. The garage is pretty large (4 car) and the boat is about 20+ feet away from the water heater.

[Sotally Tober]

Thanks. No worries on the fumes. Its not puking or fuming up the whole garage. I just changed the filler cap to a no-key style and was surprised that their was built-up pressure. The tank is not over filled its just on too much angle so I jacked up the front and will see how it goes. The garage is pretty large (4 car) and the boat is about 20+ feet away from the water heater.
It does not matter how far away the water heater is. It is the fumes that would fill the garage and start a fire. A larger garage would take more fumes to get the right mixture. Be careful!

[Outnumbered]

It does not matter how far away the water heater is. It is the fumes that would fill the garage and start a fire. A larger garage would take more fumes to get the right mixture. Be careful!
No fumes in garage. Thanks.