Issue with propeller zinc

[baz]

Pete: Pay careful attention to the thruster zincs. Once they're gone the metals in the thruster assembly will be 'under attack', and if that compromises the thrusters operation it will turn into an expensive repair cost. I replace ALL my underwater zincs when they are at 50% or less and they are now lasting at least 9 months with having shore power connected only every 24 hrs per week. It will not be long until I think I can go 12 months before having my diver service replace my underwater zincs. 😀

 

[Red Raven]

Curt.. Thanks a million for your help and the pix.. now I get it....I also independently thought it might be a good idea to shim one of the flat contact surfaces to snug it up a bit....
you mentioned "added transom zinc"... a separate one?, or double up on the one that's there (the studs seem long enough..)
Gonna add the galvanic isolator too.. quick question...any reccs. on type or features? (and it seems you only need one of them, connecting both shore power inlet plug grounds to the one terminal of the isolator ?)
and one final pestering.... my thruster zincs totally vanished also... any suggestion?
I was addicted to the shore power for my first year... I will most certainly change that this year !!
Thanks again
Pete

Hi Pete,

We have an R27 that did not have a transom zinc when we purchased the boat. The only bonded zinc from the factory was the prop zinc. The “additional” transom zinc is additional to the prop zinc. I added a Mini Divers Dream. If you already have one that should be sufficient. The only way to know for sure is to buy a silver silver chloride reference and measure the galvanic potential of your bonding system. Like this one.

https://www.boatzincs.com/corrosion-reference-electrode-specs.html

Yes, one Galvanic isolator should work but you need to have the larger 60 amp version since I think you have two 30 amp receptacles. I used the Pro Mariner brand recommended by RT. Our thruster zincs last 6 months so that works for us as we pull the boat every fall. If yours are not lasting till haul out then you need to hire a diver to replace the zinc on a more frequent schedule.

Curt

 

[bill46]

Factory sent me a washer and new screw with mine. Washer helps.
If you are losing zincs you need to add a galvanic isolator, the one thing RT forgot! Guess they think everyone keeps on trailer.