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Old 06-04-2021, 08:47 PM   #10
rgano
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City: Southport, FL near Panama City
Vessel Name: FROLIC
Vessel Model: Mainship 30 Pilot II since 2015. GB-42 1986-2015. Former Unlimited Tonnage Master
Join Date: Oct 2007
Posts: 4,984
Quote:
Originally Posted by Marinex View Post
I replaced the thru hulls when we got the boat ten years ago as they were original and some were frozen, also some fuzz around each. We left them isolated and unbonded and have had not an issue at all since then. If a system is fully bonded as Nigel Calder says "in perfect condition" and monitored then you probably would be okay. But if a bonding system is installed and not balanced to the total zinc amounts then the sacrificial link becomes your wood boat. In our case under the genset and hidden, fortunately we caught it before really serious wood issues arrived.
My Electro-Guard had a rheostat to let me adjust as necessary to keep the meter in the green as zincs/bottom paint aged. Yes, the copper-laden paint is involved too. Ref zinc rarely replaced, and the sacrificial about every year. That big plate I see in a photo above was twice as big as my Electro-Guard would stand. I put one like that on one time and the meter pegged until after several cuts, it was half that size (42 foot boat). I do not see why it seems to be a hard thing to ensure the bonding is in good shape. I managed with 11 thru-hulls, twin shafts/rudders, four fuel and two water tanks. I took a crawl through the bilges once every year to make sure it was all shiny, and the E-G would let me know if something were askew. I moved in or left more than one transient marina when I pulled in to find the meter pegged due to marina dock issues.
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Rich Gano
FROLIC (2005 MainShip 30 Pilot II)
Panama City area
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