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Fuel tank venting pressure and vacum separately FL14LS +10%

Posted: Tue Nov 17, 2020 6:08 pm
by VT_Jeff
I'd like to vent for pressure outboard and vent for vacum inboard(under the deck where the tank is) to eliminate the chance of siphoning water if/when I bury the bow. The P-trap style vents don't give me a lot of confidence that they will work in a submersion situation, they seem more geared to keep spray out.

For it to work, I'd need one-way valves on both sides, one outgoing and one incoming. Can anyone tell me if the appropriate valves exist and where I might find them? I'm concerned about the fuel pumps ability to overcome whatever resistance a check-valve may have and allow free air flow. On the pressure side, not as much of a concern, I think.

Thanks,

jeff

Re: Fuel tank venting pressure and vacum separately FL14LS +10%

Posted: Tue Nov 17, 2020 7:23 pm
by fallguy1000
VT_Jeff wrote: Tue Nov 17, 2020 6:08 pm I'd like to vent for pressure outboard and vent for vacum inboard(under the deck where the tank is) to eliminate the chance of siphoning water if/when I bury the bow. The P-trap style vents don't give me a lot of confidence that they will work in a submersion situation, they seem more geared to keep spray out.

For it to work, I'd need one-way valves on both sides, one outgoing and one incoming. Can anyone tell me if the appropriate valves exist and where I might find them? I'm concerned about the fuel pumps ability to overcome whatever resistance a check-valve may have and allow free air flow. On the pressure side, not as much of a concern, I think.

Thanks,

jeff
Not allowed if I am following you correctly.

Re: Fuel tank venting pressure and vacum separately FL14LS +10%

Posted: Tue Nov 17, 2020 7:37 pm
by VT_Jeff
fallguy1000 wrote: Tue Nov 17, 2020 7:23 pm
Not allowed if I am following you correctly.
Maybe thats why I'm not finding any info on doing that. Appreciate it.

Re: Fuel tank venting pressure and vacum separately FL14LS +10%

Posted: Tue Nov 17, 2020 8:20 pm
by fallguy1000
If you bury the bow; it is a pretty dangerous situation. If you bury the stern; the boat sinks. Any way you can move the vent further aft?

Re: Fuel tank venting pressure and vacum separately FL14LS +10%

Posted: Tue Nov 17, 2020 8:36 pm
by VT_Jeff
fallguy1000 wrote: Tue Nov 17, 2020 8:20 pm If you bury the bow; it is a pretty dangerous situation. If you bury the stern; the boat sinks. Any way you can move the vent further aft?
I can. Would I need to step up the diameter as the length increases to avoid resistance? Tank is in front.

Re: Fuel tank venting pressure and vacum separately FL14LS +10%

Posted: Tue Nov 17, 2020 10:19 pm
by fallguy1000
VT_Jeff wrote: Tue Nov 17, 2020 8:36 pm
fallguy1000 wrote: Tue Nov 17, 2020 8:20 pm If you bury the bow; it is a pretty dangerous situation. If you bury the stern; the boat sinks. Any way you can move the vent further aft?
I can. Would I need to step up the diameter as the length increases to avoid resistance? Tank is in front.
Nope

Re: Fuel tank venting pressure and vacum separately FL14LS +10%

Posted: Thu Nov 19, 2020 11:52 pm
by TomW1
I can only type one handed due to my shoulder replacement surgery. This has been discussed a lot on here, do search. Go to the store also to get an idea of the hoses and vents you will need. The vent for the tank will need to face to back as as will the fill vent. You will make a loop in both hoses to keep water from coming in.

Tom

Re: Fuel tank venting pressure and vacum separately FL14LS +10%

Posted: Fri Nov 20, 2020 10:43 am
by VT_Jeff
TomW1 wrote: Thu Nov 19, 2020 11:52 pm I can only type one handed due to my shoulder replacement surgery. This has been discussed a lot on here, do search. Go to the store also to get an idea of the hoses and vents you will need. The vent for the tank will need to face to back as as will the fill vent. You will make a loop in both hoses to keep water from coming in.

Tom
Appreciate the input, esp under duress!

Re: Fuel tank venting pressure and vacum separately FL14LS +10%

Posted: Sun Nov 22, 2020 12:01 am
by BarraMan
You're overthinking it! :D

Re: Fuel tank venting pressure and vacum separately FL14LS +10%

Posted: Sun Nov 22, 2020 5:57 am
by cape man
DO NOT LOOP THE FILL LINE! You will not be able to fill the tank. Once full you close it, so you don't need the loop.