Fuel Tank build

[warthog5]

Here's some things I've learned. When testing a tank under preasure.
1st you only need about 1lb of preasure. I took it to the high side of 1lb. IE the needle on a 0 to 15lb guage was just to the right of the 1lb mark and it was touching that mark.
THAT'S IT NO MORE!

My brother has a really sharp guy working for him he said if you take it to 4lbs that sucker will unzip itself. I belive him.[^]






Here's some interesting data from brother Rick.

Here is something you can show to the people that think you should
pressurize your tank to several psi for testing. I put together a quick
model and analyzed it in my finite element program (stress analysis). I
modeled it to the same dimensions as your tank and even put in the interior
baffles as they add to the rigidity of the tank. I then put a load of 1 psi
internal pressure. You can see the results. The max stress is the orange
area which equals 130,599 psi. Just so you know, the material we used
yields (permanently bends) at about 100,000 psi. I assume what is happening
is that the area that is permanently bending is small and that is why it is
not showing up. However, it probably won't take much higher pressure to
open this thing up. The orange areas show you where it will most probably
open up first.

[Finster]

Gotta love CAD, Nice welds, looks great. That's aluminium isn't it? USCG won't certify stainless tanks anymore.

[PipeDreamsMarine]

nope.. she's Stainless Steel... [img]/images/graemlins/shocked.gif[/img] [img]/images/graemlins/shocked.gif[/img] [img]/images/graemlins/shocked.gif[/img] [img]/images/graemlins/shocked.gif[/img]

Warhog.. why SS tank?

[warthog5]

Yes it's ALL stainless steel. It will still have a Coal Tar epoxy coating on the outside.

[Finster]

Yeah, I had a beautifull 130 gallon belly tank that I tired to get recertified and no one would touch with a stick. And the USCG doesn't like them because the welds are prone to give out. The freak'n thing had to weigh 300lbs. [img]/images/graemlins/shocked.gif[/img]

[Scott]

I'm not sure I understand ....

Bobby .... feel like we are ganging up on ya with the questions... but the pressure testing ... is 1 "lb" (psi I assume) appropriate ?? I ask only because of what the Federal Regulation states (or at least how I read it) ....plus I know the tank builders around here all mention and build to the CG/Federal standards and they typically test to 5 psi …even mentioned on their websites

Does the 1 psi pressure test fit within the Federal requirements ? Is the caveat in #2 below ?

Maybe I don’t understand the methods of testing or the numbers being thrown around here….or maybe it has to do with the malleability of Aluminum vs Stainless?


Quote from Boatbuilder handbook
Title 33 CFR, Sections 183.501–183.590
FUEL SYSTEMS
Revised November, 2003

“FEDERAL LAW:
183.542 Fuel systems.
(a) Each fuel system in a boat must have been tested by the boat
manufacturer and not leak when subjected to the greater of the
following pressures:
(1) Three pounds per square inch; or
(2) One and one-half times the pressure created in the lowest part of the
fuel system when it is filled to the level of overflow with fuel.
(b) The test pressure shall be obtained with air or inert gas.”

[pelican]

Originally Posted by warthog5

Yes it's ALL stainless steel. It will still have a Coal Tar epoxy coating on the outside.

and notice the fact that coal tar epoxy has peeled off in sheets...


every time I read ANYTHING this guy types I laugh !

warthog ?? should "bobby the butcher"...

[strick]

Originally Posted by pelican

and notice the fact that coal tar epoxy has peeled off in sheets...


every time I read ANYTHING this guy types I laugh !

warthog ?? should "bobby the butcher"...

So you never screwed up before? My guess is you got booted out of kindergarten for not playing nice.....

strick

[strick]

Originally Posted by pelican

I've made many mistakes... you ??

Yep I've even posted many my of mistakes on the internet for all to see....you?


strick

[bitsamonkey]

I followed this guy's build and really liked a lot of the things he was doing at the time. You leave yourself very exposed when you basically blog an entire build and it's easy to criticize with hindsight. I've redone a couple of boats and looking back there's always something I would have done differently.
What is interesting about this build is that he sold it online with pictures of how it's aged, and it's got more problems than just that fuel tank.
The durabak floor, which the company used as a testimonial in their ads, is a disaster.
The balance of the boat is so completely off with those two 4 strokes hanging off the bracket that the motors are totally corroded up and under the cowlings.
After all of that work, time and money, painting his truck to match and everything the poor guy manages to put about 200 hrs on the boat before selling it.
Jack of all trades, master of none can end in serious disappointment if you're building your "dreamboat". Boats that work properly and look great doing it are no accident.