About common agrrangement the gasoline fuel tank

I have a question, I split the one gasoline fuel tank into two gasoline fuel tank, because the bulkhead of the structure.
So, if I use that the pipe connect the two gasoline fuel tank? this plan could do?

 

Is that a side view or a top view?
Do they have two separate fill inlets?
How many outlets?
How big are the tanks?
What size is the 'connect piping' ?
Is the connect piping flexible hose?

 

No, unfortunately not as per ABYC
For GASOLINE, you cannot joint the bottoms of any fuel tanks.

You need to install two draw tubes, each fitted with antisphon valves then a valve to select between each of these tanks ( see below for an alternative **)

Does your boat have return lines? And what is the material of the tanks, aluminum or steel?

Re your drawing, you would not need 3 connect lines in any case

**If you installed two draw tubes and two antisiphon valves you could "Y" the two antisiphon lines and draw from both tanks simutaneously but this can create a problem in the future. If the lines are common and offer the same pressure losses/resistance, the fuel pump will pull an equal amount off each tank so that the level remains the same BUT, if you have a restriction in the antisiphon valve, ie accumulation of dirt, more fuel will be pulled from the fuel line of least resistance and depending on the location of the shut off valve etc, may never equalize. So when one tank, the one that has the least fuel line resistance gets low enough to draw air, you will never get the fuel out of the other tank.

My previous question about the engine having a return fuel line is of extreme importance, you need to check this out

 

The pickups have to be from the top,not any of the sides. A three way valve would be a good choice in case one tank empties before the other on gets contaminated.

 

No, the pipe is stainless steel.

 

So then the connecting pipes are stainless welded to a stainless tank?

 

An interesting standard about stainless tanks in the ABYC manual, H.24.18.2.2 Stainless steel gasoline tanks shall be cylindrical, with domed heads, and a capacity of less than 20 gallons, 75 litres

 

No, this engine is outboard.

Stainless steel

 

No, I use the flanges or the coupling.

 

So the joint will then be solid as it is unlikely that the coupling would be able to move a bit. Therefore when the tanks are moving slightly but independent of each other, you will have some strain, flex, within the materials elastic range.
Stainless, the effects dependent on what series that the tanks are made out of, can work harden, become brittle and crack at loads well below their ultimate strength. The openings that you have for these flanges, couplings would not meet the ABYC
guidelines. The reason being is that the are not as safe as they should be. Any holes that are in a gasoline tank, (ie a drain hole for cleaning) must be terminated by a tapered pipe plug.

Another footnote in the manual is that even if the tanks are stainless and below 20 gallons (75 litres) the only allowable alloys are 316L or 317L
The L is for low carbon and when welded offers more corrosion resistance at the weldment than non "L" designation

 

I already design the fuel supply line(P3), those piping feed the Outboards, the Outboards not need return oil. The V1 is quickly close valve.
That is to say, those tanks feed the Outboard that respective, but, if I use that three pipes connect the two gasoline fuel tank? this plan could do?

 

Oh, those tanks will fill PU of round.

 

You are using two deck fills and you illustrate two fuel lines going to the outboard. What is the reason to have non compliant and unsafe connecting pipes between the tanks. (the deck fills and tanks must be grounded by the way)
So your question "Will this plan do" No. Not if you want to be compliant. If at any time you have the boat surveyed by a qualified surveyor, say for insurance purposes or financing purposes (by either you or a future buyer) he should notice that the tank material with the size of the tanks that you have do not meet standards and your connecting pipes do not meet standards.

I do not understand your comment in your subsequent post "oh, those tanks will fill PU of round"

 

Two separate pick-ups with a Y junction into a single delivery line may indeed drain unevenly, but if it happens, a ball valve on both lines before the "Y" junction will prevent the scenario of not being able to draw fuel from the tank that isn't empty.

 

you mean an on off valve on both lines before the Y, that was the first recommendation