On Thu, 30 Oct 2003 09:55:53 -0500, "Gary Warner"
wrote:


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?

BOOOM!

#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).

Static grounds don't have to handle major lightning strikes, just
provide a leakage path to bleed off the charge before it sparks. The
electrons don't produce BOOOOM!, the heat from the spark does. It's
the heat that sets it off.

#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?

Naw....it leaks off quite nicely. My tank is polyethelene in my cheap
Sea Ray. It's just sitting in the bilge, held in with a couple of
little plastic angle brackets and some chewing gum. Polyethelene is
one of the finest insulators we know of. Take a poly bag and shuffle
it across the bed in the dark. It looks like a miniature thunder
storm!

#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 ??

Yes, these hoses are CONDUCTIVE back to the grounded pump. Conductive
rubber is used on airplanes for tires for the same reason, to bleed
off static buildup.



Larry W4CSC

"Very funny, Scotty! Now, BEAM ME MY CLOTHES! KIRK OUT!"