Gas Tank Fitting Placement

[Curious]

I'm getting ready to replace the gas tank in the 78 22 Family Fisherman.  I have a question on the placement of the fittings:



On the original tank the vent is way in the rear and the draw tube is near the center with a tube going to the bottom/rear of the tank.  I have asked the welder to move the vent up next to the fill tube and the draw tube back toward the rear of the tank.  Is there a reason why the tank was set up this way and would the changes cause any problems?
Thanks, Dan

[Capt. Bob]

OK,
I'll guess.

I don't think (other than convenience) it really matters where the vent exits the tank. I had mine constructed as you stated with the vent adjacent to the fill. Both are now accessible via one deck plate. My dual pickups are located in the rear of the tank (stern).

My guess would be that the vent location was the vent location as described (didn't really matter) and that maybe the thought for the center mount of the pickup tube was to ensure that fuel was available with a low fuel level in a heavy sea. That is as fuel transfers fore and aft in a heavy sea, the baffles (if they are present) would help concentrate fuel in the midsection as opposed to either end.

That's as stated earlier, a very big WAG.
Sounds good though.

[Blue Agave]

No worries, should work just fine.

[fitz73222]

Interesting, most vents are adjacent to the fill anyway. Looks like an original tank given the direct reading mechanical fuel gage. The challenge will be to replace the fill and vent hoses that are normally entrapped with foam. They should also be replaced with new fuel tank. You're also going to need run wiring to replace with a new fuel sending unit unless you are going to use the mechanical gage.

[dirtwheelsfl]

If the boats sitting on a pretty good bow up slope, then the vent in the rear would not let you fill up the last few gallons. I think fill and vents should be toward the front of the tank, and pickups middle to rear. Id have the vent moved near the fill for sure though...

[Curious]

Judging by the condition of the tank it was most likely original.  Just a weird setup with the pickup and vent.  Makes me really wonder if it was set up that way for a reason.  The pickup tube goes down into a 90 degree sweep, through the rear baffle and towards the rear of the tank right at the base.  Why not place it at the rear to begin with?  Same theory with the vent.  Isn't forward better?  Anyways, the folks building the tank indicate that its all good to change it around so I'll defer to them since I know less than nothing about boat fuel tanks.

As soon as things get underway I'll start a thread on the project.

In the meantime, I'll be hunkering down with the "Blizzard of 2013".  Or is it Nemo?  To us, it is just another nor'easter.  Although they are calling for 29 foot waves off our southeastern shores......

[Curious]

Survived Nemo.  Highest gust on the island was around 80 mph.  Anyways, I think one possibility for the draw tube being near the middle of the tank with an internal tube going to the bottom/rear is for clearance?  If you look at this picture, the tank coffin is deep in front and shallow in the rear:



  It still doesn't explain why the vent is way back there though.  I think we may have come up with a solution.  I'm having the tank made by Luther's Welding in Bristol, RI and they are going to install female pipe fittings in the area of the original vent fitting and near the fill.  That way I can try the vent up front and if that works then I can plug the rear fitting.  I'll leave the coffin cover loose until after the first few test runs in case I need to change anything.  

The guys at Luther's have been great and their price quote is very reasonable.  At least one other member has used them and was pleased with the results.

[wingtime]

Here is a link to how I built the tank for my 200XF.  I placed the vent at the forward end of the tank the fill in the middle and the pick up at the aft end.

http://www.classicaquasport.com/phpbb3/viewtopic.php?f=2&t=4460&p=28127&hilit=fuel+tank+cover#p28127

[Curious]

Thanks wingtime,
With that setup have you experienced any problems drawing and venting?  Also,most posts I've read state that 5200 wont adhere to starboard.  Have you noticed any problems with your install?  Good looking tank, kinda sucks to cover it up!