Rudder Post as SSB Ground?

[Mehalah]

Mehalah has, I think, a reasonable SSB installation. Short, thick, fused cables direct from batteries, new cables to tuner and a good backstay antenna.

I can use Sailmail quite effectively but there is a lot of interference when I try to join a net. I think this is mainly because the copper grounding strip is a deteriorating, corroding mess connected to nothing.

There are no bronze through hulls close to the tuner that I could use but there is a lovely shiny 2 1/2" thick solid stainless rudder post going down into the sea water.

Can I use this rudder post as my new ground and if so should it work?

Also, and this just shows my ignorance, is current only set up in an HF ground when the set is switched or is there always a current passing through it with the possibility of corrosion?

[stormalong]

Tell us more about your boat. Not enough information for a good answer.

What is the boat make and model? Is this a monohull? Does it have external ballast? Do you have access to the keel bolts. The rudder post is not much surface area In contact with the water. Even grounding to an internal ballast would, IMO be better than a rudder post.

[goboatingnow]

There is no need for seawater connection for an Rf ground connection , adequate conducting area near to seawater is sufficient , use coupling capacitors to block dc.

[Celestialsailor]

Originally Posted by goboatingnow

There is no need for seawater connection for an Rf ground connection , adequate conducting area near to seawater is sufficient , use coupling capacitors to block dc.

I would have to disagree. I went the whole copper sheeting in the bilge and struggled with performance. I finally read this article from Gordon West and never looked back. https://www.yumpu.com/en/document/re...d-boats-these-
Eventually put a copper plate outside the hull in the radio area designated solely for the radio ground plane.

[qwert]

I know very little about radio and its connections so forgive me if this is a stupid question, but with a backstay aerial is there any chance that the

" lovely shiny 2 1/2" thick solid stainless rudder post going down into the sea water".

might become a rather efficient lightning conductor right through the middle of your steering apparatus...?

[GordMay]

Greetings and welcome aboard the CF, Mehalah.

[boat driver]

need more info on the rudder post- if the post is enshrouded in fiberglass then it may not have sufficient ground/seawater contact. If it is well exposed, it works.

otherwise, use seacocks,

[guyrj33]

I would start by replacing the copper grounding strips. If you need a ground you could connect to the engine it should be grounded to see water.
But if you’re how is fiberglass, it should be OK without a separate sea water ground as fiberglass is transparent to RF energy. Think about radar domes as an example.

[Mehalah]

Hey

Thanks for all the replies!

stormalong: She's a 1983 Sparkman and Stevens 47' monohull. THICK fibreglass. Encapsulated keel. No keel bolts. 1" of post , unsheathed evident beneath the hull. Bronze through hulls, bonded with a green wire. Centre cockpit so nearest seacocks forward of aft cabin.

celestial sailor: I would prefer no more holes in the hull if possible. Great article from Gordon West. Thanks.

boat driver: As above, 1" of exposed s/s post beneath the hull.


I realise there is a big debate through hulls v internal copper strips v Kiss. My inclination at the moment is make an easy connection to the rudder post and potentially extend to the three nearest bonded through hulls about 4m away if necessary.

[Frankly]

Try a short wire connection to the rudder post and see if it improves things. I connected my HF ground to my SS centerboard cable pipe. On 14,300 Mhz works just as well as a jumbo Dynaplate which I no longer have to scrape.


Frankly

[wholybee]

I would try to avoid connecting to a moving part. Otherwise a rudder post should work fine, but mind the connection to ensure it doesn't fail from the movement. You do not need as much surface area as most people suggest if there is a direct connection to water. If you are creating a ground plane without a connection to water, then you need a lot.

In theory, the icom tuners have a capacitor on the ground connection to block DC against corrosion. However, not all of them do, so many people install a capacitor(s) in the copper strip. Just cut the strip, and use several capacitors to bridge the gap.

[Brian.D]

https://briandphoto.net/Ground.html

[wcapman]

Using a rudder post for a ground might not be a good idea. If this is a typical design, there is a metal quadrant attached to the post in full electrical contact. This has steering cables and chain to a gear at the wheel. In other words full electrical contact to your hands on the wheel. And to the autopilot. It is far better to keep the ground isolated from body parts and electronics. A separate ground plate close to the transmitter is always best for safety. Also keep in mind this is not a DC ground but an RF ground and as such you can get significant burns connected to an RF ground, especially if you also contacted the backstay during transmission.

[Mehalah]

Wcapman:

Originally Posted by wcapman

If this is a typical design, there is a metal quadrant attached to the post in full electrical contact. This has steering cables and chain to a gear at the wheel. In other words full electrical contact to your hands on the wheel. And to the autopilot. It is far better to keep the ground isolated from body parts and electronics.

Yes. This is indeed the setup on Mehalah and is perhaps a good reason to not use the rudder post.

Let's suppose I run a good copper strip to the three bonded through hulls instead, a distance of between 3 and 4 metres from the tuner. Any problem with that (other than it might be too long a run)?

[Celestialsailor]

Originally Posted by wcapman

Using a rudder post for a ground might not be a good idea. If this is a typical design, there is a metal quadrant attached to the post in full electrical contact. This has steering cables and chain to a gear at the wheel. In other words full electrical contact to your hands on the wheel. And to the autopilot. It is far better to keep the ground isolated from body parts and electronics. A separate ground plate close to the transmitter is always best for safety. Also keep in mind this is not a DC ground but an RF ground and as such you can get significant burns connected to an RF ground, especially if you also contacted the backstay during transmission.

Also a pathway for stray currents.