Bonding

[Offshore]

My main eng thru Hull doesn't have a bolt to attach a bonding wire. Anyone experience that and a fix ?

 

[tiltrider1]

Hose clamp when all else fails.

 

[TJM]

I second the SS hose clamp. Conductivity is the solution with a GREEN wire.

 

[Offshore]

BUTY are Stainless and Bronze going to get long ?

 

[BB-marine]

The stainless steel hose clamp method is a last resort in my opinion. Stainless steel and bronze are galvanically incompatible. Add the copper tin wire to the equation and there is probably going to be some corrosion and the bond will be incomplete. A bronze grounding pipe clamp would be a better alternative. This type of clamp is commonly used for grounding gas and water pipes in residential and commercial installations. The clamps are available in 1/2" dia. to 4" dia. The thru hull fittings are bronze so install a bronze clamp.

Using the stainless steel clamp as a temporary bonding repair would be a satisfactory repair. The worst case is you end up with what you have now. No bond. The question I have is what issue are you having with the non-bonded through hull? Has it been this way since the boat was built? If so is it damaged? Sometimes the thought process of ( if it works don't change it) works.
Brian

 

[Bmarler]

Agree with Brian, you don’t know if it needs to be connected to the bonding system until you survey the under water metals with a reference cell.
I have under water through hull fittings not bonded that read perfectly fine.

 

[tiltrider1]

We can go down the rabbit hole of does the bronze thru hull even need to be bonded. Most struts are bronze and held on with stainless bolts. Attaching a stainless hose clamp to a bronze thru hull won’t set off any significant galvanic corrosion issues.

Is it a permanent fix? I would say no. I would say it is a 5 year fix then reinspect. A bronze gas clamp would be a better solution if the correct size can be sourced.

 

[BB-marine]

We can go down the rabbit hole of does the bronze thru hull even need to be bonded. Most struts are bronze and held on with stainless bolts. Attaching a stainless hose clamp to a bronze thru hull won’t set off any significant galvanic corrosion issues.

Is it a permanent fix? I would say no. I would say it is a 5 year fix then reinspect. A bronze gas clamp would be a better solution if the correct size can be sourced.

Using a stainless steel fastener to attach a bronze fitting to a hull is a different subject. 316 stainless steel and bronze are close in a galvanic series and considered a good combination when fastening a bronze component on a boat. Bronze and stainless steel are dissimilar metals and considered incompatible. Using a stainless steel band to hold a copper wire to a bronze underwater fitting that is expected to maintain continuity is a different use. It is not a question of significant galvanic corrosion issues. It is a question of surface corrosion of stainless/copper/bronze that compromise the connection. IMO.
I agree with you it will work in the short term, if it is inspected regularly and connections kept clean. It is not what would be considered a permanent fix.


Brian

 

[Don L]

A bad bonding connection corroded a thur hull fitting on my first boat and when I found it the only thing holding a 1.5" connection and keeping the boat from sinking was caulk.

 

[tiltrider1]

A bad bonding connection corroded a thur hull fitting on my first boat and when I found it the only thing holding a 1.5" connection and keeping the boat from sinking was caulk.

There is more to this story. An isolated bronze thru hull does not need to be bonded. Bonding can be a negative in cases of electrolysis. When wire reinforced hose is used, it’s recommended that the thru hull be bonded as a potential preventative measure.

 

[SteveK]

I thought dissimilar metals had to be immersed in a conductive enviroment as in water to start corrosion. A wet bilge will suffice.

 

[Don L]

There is more to this story. An isolated bronze thru hull does not need to be bonded. Bonding can be a negative in cases of electrolysis. When wire reinforced hose is used, it’s recommended that the thru hull be bonded as a potential preventative measure.

Of course there is more. There was a ground wire problem from a metal tank. But if that tank and the thru were not bonded together the thru connection would not have corroded. The bottom line is IMO connecting anything that doesn't have to be into a system that might have a potential electrical differential is crazy.

 

[J.T kearney]

BUTY are Stainless and Bronze going to get long ?

Hi
Steve D has a video out on bonding and suggest adding a ferrule to the bonding wire end for better surface contact when using a hose clamp.