External Grounding Bar Below Waterline?

[islandseeker]

Hello, I have seen some Brass grounding bars used for electronics grounding, ( mounted on the outside of the hull with studs into the bilge for connection points) as I understand it. Does anyone out there have one of these on thier vessel? I will have extensive electronics including SSB, AP, etc. Any opinions? Also, I have heard of grounding the mast to one of these for lightning protection? What do you all think? They seem quite spendy, How is the size determined?

Any response is appreciated, Thanks

[babylonlarry]

My Boat came with a dynaplate - a scintered bronze plate which is supposed to offer a large area of (RF) ground. It has become fouled with marine growth which, I suspect, greatly reduces the surface area.

I am a bit concerned with what would happen were there to be a direct lightning strike, as it may not be able to dissapate the charge and heat and explode.

While I have never heard of such, knowledgeable people do not dismiss the possibility out of hand.

I have thought of removing it, but haven't.

I do not like holes in the hull.

Gordon West ( a ham radio "guru") says that a bonded brass thru hull is sufficient for RF round for a HF radio. I have grounded engine, tanks, run some thin brass sheeting inside the hull under the waterline for a capacitive coupled RF ground and get out well.

[svReboot]

When I faced the same question for a new SSB transceiver I tried the following:

1. I ran a ground from the antenna tuner to one of the bolts on my keel. I did not run a ground between the antenna tuner and the transceiver (Kenwood TS-480 HX) as the shield of the coax is grounded to both the "case" of the antenna tuner and the transceiver and I did not want to provide multiple paths. I tuned the rig up and made a few contacts and got some signal reports. Then I dropped 100 feet of copper wire off the stern with one end attached to the antenna tuner ground. Repeated the contacts and got no difference in signal reports. I declared my keel just find as my counterpoise coupler.

2. With respect to a lightening strike I did not do anything to ground the mast. It is a keel stepped mast so I figure that the lightening with burn out whatever fiberglass sits between the keel and the bottom of the mast.