Grounding Gas Tank - Curious

[Gary Warner]

So yesterday we went up to see a boat restorer in upstate NY.
VERY nice guy. Anyway, while talking he reminded me that
I need to run a ground wire from my steel gas tank to the
engine or other ground point. ~ I'm sure this is a good idea
that can't hurt, but I'm just wondering:

#1 - What exactly could happen without that. I assume it's that
a static electric charge could build up on the tank or on me...and
when I touch the gas cap a spark happens in the tank?

#2 - Is the real purpose of the ground to the engine is because
the engine is grounded to the battery or is it because the engine
is connected to the drive shaft which is in the water (true ground).

#3 - What happens when the boat is on the trailer? Then none of
the boat is grounded....It's setting on wooden bunks and on rubber
tires? Couldn't I still get a spark then? ~ It's like a car...that has a
gas tank, but it's not grounded since it all sets on rubber tires?

#4 - Lastly, do the hoses at gas stations connect to ground? The
hoses appear to be rubber but I suppose maybe they are special
hoses with some ground wire embedded in the rubber to take
away any static charge ??

THANKS
Gary

 

[Glenn Ashmore]

The answer to #4 is that you do have to run a separate ground wire from
the deck fill to ground. It is also a good idea to tap the fuel filler
nozzel against the deck fill before you open it to drain any built up
potential. Aircraft fuel trucks have a separate ground clip that is
attatched to the airplane before fueling to drain any charge.

So yesterday we went up to see a boat restorer in upstate NY.
VERY nice guy. Anyway, while talking he reminded me that
I need to run a ground wire from my steel gas tank to the
engine or other ground point. ~ I'm sure this is a good idea
that can't hurt, but I'm just wondering:

#1 - What exactly could happen without that. I assume it's that
a static electric charge could build up on the tank or on me...and
when I touch the gas cap a spark happens in the tank?

#2 - Is the real purpose of the ground to the engine is because
the engine is grounded to the battery or is it because the engine
is connected to the drive shaft which is in the water (true ground).

#3 - What happens when the boat is on the trailer? Then none of
the boat is grounded....It's setting on wooden bunks and on rubber
tires? Couldn't I still get a spark then? ~ It's like a car...that has a
gas tank, but it's not grounded since it all sets on rubber tires?

#4 - Lastly, do the hoses at gas stations connect to ground? The
hoses appear to be rubber but I suppose maybe they are special
hoses with some ground wire embedded in the rubber to take
away any static charge ??

THANKS
Gary

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

 

[Rick]

Larry W4CSC wrote:

Conductive rubber is used on airplanes for tires for
the same reason, to bleed off static buildup.

Larry, airplane tires are no more or less conductive than nearly any
other vehicle tire.

Do you have a book of wierd technical myths that you drag out every
couple of days or do these ideas just kind of jump off your fingertips
onto the keyboard?

Rick

 

[Gary Warner]

The only gas gauge on this boat is going to be a stick.

And our filler pipe is a nipple screwed directly to the tank.

But thanks for all the comments anyway...the common ground
ideas apply just fine.

 

[DaveH]

Aircraft hangers generally have ground points to attach the aircraft to.