I'm pretty sure that ABYC does not indeed require or even suggest bonding sea cocks or through-hull fittings:
"E 1.4 c. Items Not Required to be Bonded (I) Electrically isolated through-hull fittings need not be connected to the bonding system. (See ABYC E-2, "Cathodic Protection".) "
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I behold from the beach your crooked inviting fingers,
I believe you refuse to go back without feeling of me;
We must have a turn together . . . . I undress . . . . hurry me out of sight of the land,
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The issue of bonding through hulls seems to be a US thing (possibly wider). Certainly UK and many European boats do not have through hulls bonded together.
On my own yacht only the S/S rudder shaft is connected to the hull anode. The S/S propshaft has its own anode. The Bronze through hulls are all separate and will remain so.
Mine also
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This observation of lack of bond wire is most important comment yet! If indeed there was no bond wire, I would pull the boat out of the water soon, then yank on the valve with your gloved hand. If the assembly does not break off in your hand, the threaded thru hull fitting may still be sound. Of course with 19 years underwater, it should be removed and re-bedded at the least.
Clean it all up with CLR, then grab a wrench and pull the 90 bend and valve off the thru hull. Make sure you install a ground wire and decent marine thru hull valve.
Not at all. There is a long ongoing dispute about bonding or not bonding. Most my boats have been not bonded and the bronze etc has been very much inert and fine. In fact , Tying things together can create pathways for corrosive currents, especially if tied to the engine.
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