Rapid corrosion on motor

Jon said:
Few questions for you. Where would you recommend your grounding /bonding system be tied to? I have a fibreglass boat and what Brutus and myself believe is it’s tied to main outboard as I don’t have any true through hull fittings .
Next question what gauge wire did you run for bonding on trim tabs? If you get a chance maybe snap a pic for me .
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Says on the post 10 gauge, I think 12 or 14 would work too
 
The main motor is a good place to bond to...both my main and kicker are bonded to the bonding system...even though the main is hung onto the aluminum pod which is also bonded....the pod is powder coated so there is likely no direct metal to metal contact between them. I use green 10 gauge for all bonding. I normally replace it all every season due to corrosion...this year I didn't because of Covid and a short season and I had no problems. So I will probably go 2 years now before replacing. I will take a pic of the tabs.
 
Bonding reduces the electrical potential between 2 or more metals exposed to saltwater; in the case above the trim tabs & motor. Seawater is a pretty good conductor, so the bonding eliminates/reduces the amount of electricity that flows thru the water. The larger the wire, the less the resistance the wire has, and the electricity will flow via the wire,and the lower the electrical potential (this is good). Most stuff I just read says 8AWG or larger. My boat uses 2 inch wide copper for this. FYI these stray electrons in the water can repel fish. Thanks guys, just remembered I forgot to bond the 2 transducers I just installed.
 
So in the first pic you can see how both side of the hinged tab are bonded together...then on this side of the boat I picked up and bonded one of my transducer and bracket...from there in the second picture it travels up to the stainless fitting that all my main engine controls exit through the transom...so I didn't have to drill another hole in the transom. I drilled a small hole in that fitting to get it to the inside where it runs inside with the engine controls...the piece of hose pulls over the top of that hole and hides it.
 
Correction that wire that goes into the engine control fitting turns towards the main engine and I have it attached to a bolt on the engine block...then another wire is attached there as well and runs back inside the boat...so I picked up the main motor in that one loop.
 
profisher said:
Correction that wire that goes into the engine control fitting turns towards the main engine and I have it attached to a bolt on the engine block...then another wire is attached there as well and runs back inside the boat...so I picked up the main motor in that one loop.
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Where does this terminate after grabbing the main motor ?
 
All my bonding wires go to a bolt I had welded to the backside of one of my pod's through transom mounting bolts. Where I have a sizable bar of zinc attached. Basically took a stainless bolt and had it welded to the pod bolt..bolt head to bolt head
 
profisher said:
All my bonding wires go to a bolt I had welded to the backside of one of my pod's through transom mounting bolts. Where I have a sizable bar of zinc attached. Basically took a stainless bolt and had it welded to the pod bolt..bolt head to bolt head
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Could a guy bond everything together and terminate it at the large zinc below the trim motor on my main ? Or terminate at a grounding block from the battery ?
Bonding kicker into same series as main ?
 
My understanding is that the bonding system should be
separate and stand alone from electical system itself. That is why many marine electronics have a seperate grounding/bonding wire in addition to the positive and negative leads. I don’t have my batteries negative circuit included in the bonded system.
 
As far as using the mains engine bracket to bolt on a bar of zinc... you could but if me I would get a piece of aluminum or stainless flat bar and find somewhere it can be fixed to the transom with existing bolts..so you aren’t drilling new holes. Then have the zinc bolted or welded to that. Welding is a better connection and you could simply remove the flat bar when the zinc needs replacing and have a new one welded on at a bench.. then put back on the transom when done
 
You guys have me confused now lol, i rewired a few boat in the years, and alway bonded all the electrical in a loop, with one end of the bonding terminating either on a grounding plate attach to the hull of a through hull on the boat, all my true hull are bonded together, all the ones under water are bronze, no plastic bellow water. Am I missing something ????
 
profisher said:
My understanding is that the bonding system should be
separate and stand alone from electical system itself. That is why many marine electronics have a seperate grounding/bonding wire in addition to the positive and negative leads. I don’t have my batteries negative circuit included in the bonded system.
Click to expand...
Far as I can see my bonding is tied into the negative buss bar essentially. As negative ties into motor casing and jumper wires from different parts on the leg . Same with kicker . I need to re visit this and check with meter though out the boat.
I’m confused for sure .
 
Brutus, your system is correct. Mine is in a loop as well but mine ends at my pod bolts which are grounded to the pod itself which sits in the water with a bar of zinc welded to bare aluminum tabs on the bottom side. I've just found a way to end the loop on the inside of the hull and still be grounded to the water.
 
Think of it as a three wire 120 volt AC system. The third green wire grounds all receptacles and devices to ground and is completely separate from the energized circuit.
 
Jon said:
Far as I can see my bonding is tied into the negative buss bar essentially. As negative ties into motor casing and jumper wires from different parts on the leg . Same with kicker . I need to re visit this and check with meter though out the boat.
I’m confused for sure .
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Ya me too lol
 
Easy way to include metal thru hull fittings it to strip back an inch to 2 inches of insulation off that end of your bonding wire and then use a stainless hose clamp around the threaded stem of the fitting.....simply tighten down the clamp around the stem with the bare wire in between.
 
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