Raymarine course computer ground connection

[wiggy]

My course computer says
"3.6Grounding
These grounding requirements are applicable for Raymarine equipment with a dedicated ground terminal.
• The ground terminal must be connected to a common ground point.
• It is recommended that the common ground point is a bonded ground,i.e.with the ground point connected to battery negative, and situated as close as possible to the battery negative terminal. If a bonded ground system is not possible ,anon-bonded RF ground may be used."

What does this mean? Mine was connected to the saildrive leg of my MD 2020, this worries me as Volvo state that nothing should link the leg to earth.
I'm confused. Where do I connect this, at the moment it's connected to nothing.

 

[prv]

Mine also wasn't connected to anything. If I was installing it then I might have worried about what to do with it, but since I inherited it that way and it's working fine, I'm happy to leave it unconnected.

Pete

 

[lpdsn]

It's just to get rid of noise on the wiring. With the ACU-200 I ran OK for the first few months with the gnd point just connected to the -ve supply before I had the time to run a separate gnd to that part of the boat.

PS - the gnd connects to the keel, which is as fitted by the builder.

 

[paulbowen8]

When I got my boat the autopilot would occasionally give spurious 'Shallow' alarm display, and other times would for no apparent reason go into Standby mode. Fitting a ground wire to the course computer seems to have cured this.

 

[wiggy]

Mmmm, got me thinking, is there any risk at all to my saildrive (remember the volvo warning) with this Earth being attached to the saildrive.

 

[wiggy]

Earth connection on plastic fuel tank

I have a plastic fuel rank and it has a wire from one of the bolts attaching the filler to the deck down to the Volvo Saildrive.
Is this normal?
What does it do?
Could my saildrive vanish in a puff of galvanic corrosion?

This post follows my one about the Raymarine course computer also being grounded to the saildrive, both are disconnected at the moment.

 

[rob2]

I have a plastic fuel rank and it has a wire from one of the bolts attaching the filler to the deck down to the Volvo Saildrive...
Could my saildrive vanish in a puff of galvanic corrosion?

I suspect that the wire is to earth the filler to discharge static from the fuel hose. This is relatively normal for a petrol tank, but not considered necessary for diesel. Of course it's best to earth the hose before fuelling so any sparks don't see the fuel! Mind you, there is no earth when you fuel your car, is there? Volvo don't like anything wired to the leg, presumably to avoid some numpty bridging the isolation twixt engine/leg/propeller and any continuous currents. The filler neck on its own, though, should't generate a current as it is not immersed in the seawater - to be sure you'd need to make sure nothing else is connected to it.

Rob.