Unbonded thru hulls

New to me Mainship 350 trawler. As I go Below deck working on versions projects I keep finding that the green bonding wire To all of the thru hulls have been purposely disconnected and the terminal ends taped over.
What would be the reason to disconnect the bond wires from all the thru hulls?

There is a decent argument that bonding thruhulls doesn't help much. Obviously that is what the previous owner believed. Mainship used to build them with bonding, so.....

David

I would reconnect the bonding wires to the underwater metals. Steve D has some good articles on his web site dealing with this.

Certain bottom paints react when bonded to the zincs. This shows up as rings of no bottom paint around bronze thru hull fittings. It is a common reason. For PO’s to cut the bonding wires.

I do not bond thru hulls, The other view on the topic
https://www.westmarine.com/WestAdvisor/Marine-Grounding-Systems

Bonding and Electrolytic Corrosion Due to Hot Marinas
Do not bond any thru-hulls or other immersed metal that can be electrically isolated. Specifically, keep your metal keel/ballast, your metal rudder shaft, your engine/prop, and all thru-hulls electrically isolated, from each other, and from the engine.

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Soo-Valley said:

I do not bond thru hulls, The other view on the topic
https://www.westmarine.com/WestAdvisor/Marine-Grounding-Systems

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The conclusion section of the article has the following quoted section that is less persuasive - the "don't bond" position by Stan Honey is applicable to hot marinas. He clearly states bonding helps for self generated stray current, but not stray current from other boats or sources. Would also note this article is 25 years old. Hoping Steve D chimes in

"In the old days, the technique of bonding everything together worked okay. In its defense, the "bond everything together" approach makes your boat less sensitive to electrolytic corrosion that can result from faulty wiring on your own boat. The problem is, the "bond everything" approach leaves your boat totally defenseless to wiring errors in nearby boats and nearby industry, that cause stray DC currents to run through the water."

Peter

Reconnect or not?

I just redid my electrical system. After reading Steve Ds articles, I went heavy #6 wire on bonding system.

Peter

mvweebles said:

The conclusion section of the article has the following quoted section that is less persuasive - the "don't bond" position by Stan Honey is applicable to hot marinas. He clearly states bonding helps for self generated stray current, but not stray current from other boats or sources. Would also note this article is 25 years old. Hoping Steve D chimes in

"In the old days, the technique of bonding everything together worked okay. In its defense, the "bond everything together" approach makes your boat less sensitive to electrolytic corrosion that can result from faulty wiring on your own boat. The problem is, the "bond everything" approach leaves your boat totally defenseless to wiring errors in nearby boats and nearby industry, that cause stray DC currents to run through the water."

Peter

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The bolded above is all I need to not bond everything together and allow stray current from others access to my ground.
My AC and DC negative/ground are bonded to protect inside the boat, but that is not connected to the water, to any thru hull, shaft or zinc. Nothing leaves, nothing enters.

Soo-Valley said:

The bolded above is all I need to not bond everything together and allow stray current from others access to my ground.
My AC and DC negative/ground are bonded to protect inside the boat, but that is not connected to the water, to any thru hull, shaft or zinc. Nothing leaves, nothing enters.

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Stan Honey is one of the great ocean cruisers and racing tacticians ever. But for me, his 25-year old guidance in a field for which his credentials are less established just doesn't offset the guidance from Steve D who advocates a robust grounding system that also may also reduce severity of damage from a lightning strike (emphasis on 'may'). But it's a good point and I hope Steve D chimes in

Peter

It’s one thing if we are talking about unbounded bronze thru hulls. It’s another thing if we are talking about a bronze strut using stainless steel bolts. I am in the bonding camp unless we are talking about a wood hull.