Exactamente Dodgy 👍
Martin is also correct.
Point 2 was discussed a few days ago in a similar thread.
The earth wire should be soldered or clamped to the prop tube of earth plate though.
A loose connection like a croc clip can itself be a source of interference; so called "Metal to metal noise". That's also why I don't like all metal UJs for the prop shaft.
Even 1:1 ships can suffer from problems with earthing plates
In the mid nineties I designed a COMMS system for a series of glass fibre minesweepers.
Against my better judgement the yard decide to use vertical whip antennae for the HF radios
A vertical monopole whip antenna needs a good earth to act as it's counterpoise.
"No problem " said the yard "We'll let a copper earth plate into the keel."
After launching and a few weeks of fitting out and trials they complained that the HF comm efficiency and range was deteriorating. We tested all our radios
, ATU and cabling and all was OK.
Then we sent a diver down to inspect the earth plate.
He came up and said "It looks like Chantilly lace!"
Red faces at the yard and they coughed up for the Crossed Dipole antenna (with it's own built in counterpoise and ATU) which I wanted to fit in the first place 😉
Cheers, Doug 😎