Installing ground/bond wires

[tamaynes]

Here in Maine it is almost boat season so I've begun thinking about spring boat projects for our E32-200.

Last summer we found ourselves off shore in a fairly severe thunderstorm. When we returned to port I decided to check our boats bonding system and found that there is none. The mast, shrouds, stays, binnacle, etc. seem to have no connections to an electric ground of any kind.

I'm thinking of adding ground wires this spring, running them to a keel bolt. Here's the question...

Has anyone done this and can you offer advice on how to proceed?

Thanks,
Tom Maynes
Ambrevena E32-2
Boothbay harbor

 

[ted_reshetiloff]

Step one: Drive to local Auto Parts Store
Step Two: Purchase set of battery jumper cables.
Step Three: Store cables on boat, attach to shrouds and toss other end in water when next thunderstorm approaches.
Step Four: Rinse cables with fresh water and store in dry place.

There are lots of theories on the merits of bonding however my personal experience has been that bonding causes damage to boats from galvanic corrosion. YMMV.

 

[mherrcat]

Ha Ha!
I was wondering if there was a temporary solution to this!
Is this for real or just a joke?

 

[Frank Langer]

I have also read about hooking cables to the shrouds during a thunderstorm and dangling the other end in the water to provide a pathway for the lightning, so I think Ted is not necessarily joking. I'm sure it wouldn't be quite as effective as a grounding system, but I have also heard about corrosion problems resulting from the grounding system. There doesn't seem to be a perfect solution.
I have decided not to install a grounding/bonding system on our boat. Fortunately, we are in an area where there aren't too many thunderstorms, and I hope that by the time the storm does hit, I'm in the pub.

Frank

 

[Emerald]

I've been avoiding this thread, as lightening is one of those charged topics that attracts all sorts of hits....

You'll get as many opinions on this as blister repair, so good luck, but here it goes. The primary objective is to give the lightening a path of least resistance to ground. Lightening doesn't like to make turns, and wants to go straight if possible. It can jump. I think I've probably read as many accounts of boats with grounding/bonding plates blowing holes in their hulls from a hit as not, so I personally would avoid them, even though some will praise them. I agree with Ted on creating galvanic issues tying it all together. Perhaps if I was keel stepped I would try to tie the engine to the mast base, but as deck stepped, I think I'd leave them separate and hope the lightening went down the shrouds. I'd hate to bond the engine to the mast and blow the stuffing box out of the boat and sink from a hit that way. Has anyone ever heard of that scenario?

I've used jumper cables as Ted describes. Never taken a hit with them, so can't comment on their effectiveness. I've also heard of keeping chain for the same purpose. Just wrap the chain several times around the base of the shrouds and hang overboard. Somehow I've come away with the impression that the chain wraps do a better job of getting the lightening to follow it to water than the jaws on jumper cables, due to more surface contact area.

I have one personal experience with a pre-lightening hit. This was many (like 35) years ago on a Tartan 34. We were anchored on a "nice" afternoon and as a storm approached, our rigging started to buzz. I want to say the hair on our arms also started to raise. My father went below and disconnected the VHF antenna and made a connection to a bonding/grounding plate of some sort, and in the process got a nice electrical zap that knocked him on his rear, and the buzzing in our rigging stopped. It is my understanding that we were building up a charge in our rigging and were about to get hit. So, here's one where a grounding/bonding plate did protect us. I wish I could go back and hang cables/chain off the shrouds to see what would have happened. With this experience you'd think I'd be all over plates, but I've heard of too many stories of plates sinking boats to feel comfortable installing one. So cables/chain would be my current choice.

And then there are the creatures that look like a bottle brush on your mast head that are, I believe, supposed to dissipate a charge at the ion level. Seems I've heard as many arguments for them helping as hurting, like most lightening remedies.

Any other first hand experiences out there?

 

[Tom Metzger]

David - You are correct; grounding the rig will allow charge to bleed off and reduce the likely-hood of a strike.

BTW, One should not put oneself into the current path as your father did. :nerd:

 

[Emerald]

David - You are correct; grounding the rig will allow charge to bleed off and reduce the likely-hood of a strike.

BTW, One should not put oneself into the current path as your father did. :nerd:

Yeah, I think he'd second that about not getting into the current path. Saying he got knocked on his rear is a bit of an understatement, as I think about it. If I remember this correctly, it literally was taking the antenna from the back of the VHF and connecting it to the plate. This was obviously a close call, and we're really lucky he didn't get fried and we didn't get struck.

 

[Lucky Dog]

I am not expert,

The path of least resistance is does not include any change of direction greater than 10 degrees. I agree with the battery cable idea, hoping the lighting follows the shrouds and not the mast.

One of the presentations at Strictly Sail in Chicago this year, told a great story about taking a direct hit while anchored. They were not the tallest boat, plenty of other boats surrounding them, not the closest to land or the farthest.

His wife was about to come on deck to see where the storm was, when they were hit. Sent her fly into the forward berth from the companionway. When they went on deck it was on fire from all the extreme heat and sparks. They lost all electrical and followed another boat into a harbor where their was hospital.

They ended up rebuilding the boat and his wife suffered minor injuries, once they were at a hospital. I believe they had a grounded boat.

Best part of the presentation. Was up to Garrison Keillors standards.

ml

 

[tamaynes]

Boat Grounding

There certainly is a diversity of opinion on this subject. I don't think it is reasonable to expect that a grounding system or one of those little brush things will somehow protect a boat from a lightning strike. The energy involved in such an event is simply too great. Furthermore, I don't think it is reasonable to protect electronic equipment from a direct strike for the same reason. My primary concern is to ensure that lightning striking our boat finds a way to ground without blowing out a plastic seacock, or passing through me or my crew to get there.

When we were in the storm last summer we had about 1/2 hr warning via NOAA weather radio, and that time was spent preparing the boat and crew... sails, fowl weather gear, etc. During the storm the wind was in the 40-50mph range and we were pretty busy with things flying around, (our radar reflector broke away from a spreader and was dragging in the water). So, from that experience I think that an external grounding "jury rig' is an inconvenience and something I'd rather not have to remember to do.

All that said, I've concluded that the best course of action for Ambrevena is to install a permanent ground system attached to the keel. I'll ground the engine, mast, shrouds, binnacle, and lifelines. Hope we never experience a lightning strike, but if we do a grounded boat should provide an extra margin of crew safety.

Thanks for the input,
Tom Maynes
s/v Ambrevena E32-200
Boothbay Hbr, ME

 

[Tom Metzger]

All that said, I've concluded that the best course of action for Ambrevena is to install a permanent ground system attached to the keel. I'll ground the engine, mast, shrouds, binnacle, and lifelines. Hope we never experience a lightning strike, but if we do a grounded boat should provide an extra margin of crew safety.

Tom - This is a good plan, and I am anxious to hear how you run the leads. You should use at least #4 copper wire for all of the connections and try to avoid as many sharp bends as you can.

Take lots of pics showing how you get the wires through the cabin.

 

[HughHarv]

Solid Copper Ground Wire

Why not solid 4-0 copper ground wire wrapped to each shroud with several feet in the water on each side of the boat? Seems like it would be less resistance to ground than chain and less drag.

 

[Rhynie]

Story dating back to the '70's. A couple I knew back then, older than I, were experiences sailors and had retired and had bought a larger boat. As I recall, it was a Gulstar, and took delivery of it in Mobile AL. Anyway on the shakedown in the bay, she was hit by lightning; fried everything but nobody hurt. The boat was rebuilt there and a couple months later was brought to Mandeville, LA where they had a condo on the bayou. About two weeks later leaving the harbor, you guessed it, they were hit again and again nobody hurt.
Jack sold the boat and retired from sailing saying, "there damn sure wasn't going to be a third time".

There is another story from around that same time of a boat racing on Lake Pontchartrain and she sailed under a power line. She took a big hit, sails caught fire, disabled everything. They then drifted back under it and took a second hit.

 

[bayhoss]

I remember a video of a sailboat hitting overhead power lines. The boat was fair sized and equipped with a keel stepped mast. When the mast made contact with the lines there was a bright flash in the water. I would assume that to be the charge exiting thru the keel and the surrounding part of the hull. The boat sank like a rock. If overhead lines can do that than you bet lighting can do it better. I'd put the cables over the side and avoid taking a route thru the boat to the keel. Just my HO.

Best,
Frank

 

[Gary Peterson]

Confusing thing is that if one talks to 10 Physics PhDs, one will get 10 different answers. There is one agreement that there is a 45 degree cone of protection starting at the mast head for people onboard. Don't ever want to test that one either.
I'll stick with large jumper cables attached to my shrouds.

 

[Emerald]

There is one agreement that there is a 45 degree cone of protection starting at the mast head for people onboard. Don't ever want to test that one either.

That would be going with the Faraday Cage theory. I agree - not what I want to test. Seeing how I've got jumper cables and chain, but not enough of either to cover all stays, but combined can get the lot, it seems I'll go for a mixed approach.

 

[tamaynes]

To Bond... or not...

Well, I consulted an oracle... a professional boatbuilder here in Maine with decades of experience building some of the finest yachts afloat. Here's what he told me.

• All yachts he's built have had grounding systems. The primary ground is a busbar from the mast step to a keel bolt.
• He knows of no owners of his yachts, build over the past 50 years or so, that have ever been injured by a lightning strike, though many boats have been struck over the years.
• Electronics are sacrificial when a boat is struck. The little gizmos almost never survive.
• Grounding systems have not noticeably affected the corrosion rate of yacht equipment
• His boats also ground shrouds, stays, engine, binnacle, and electronics using #4 copper wire run to the same keel bolt as the mast busbar. Only one keel bolt is used for all grounds.
• Barrier coatings over a keel reduce the effectiveness of a bonding system, but bottom paint does not because it saturates with sea water.

Tom

 

[Jon Libby]

Bonding for lighting

As an electrical contractor for many years I'd come into contact at one point with an old timer that was installing a lighting rod system on a house we were wiring and ask the questions why? He explained it in a way that put it across simply, and I never forgot.

As the storm or beast is moving in, an electrical potential is building. Potential is the key word. If you lick a 9 volt battery you might feel a little tingle, if you lick the end of an extension cord that’s plugged in, you gotten get kicked in the face. The difference is potential. So as the beast is moving in, it’s building up an electrical potential between itself and earth, our goal is to be the smallest potential out there. Your mast, the witches’ broom, and anything else in the air, (the more the better) should scratch the belly of the beast and become it friend or same potential. Become the same potential as the beast as quickly as possible. If your not its friend, your its enemy and he’ll kick you in the face and soon as he has the energy. Fast moving or large storms don’t give a lot of time for potential to equalize, that’s why we see lots more strikes with these than slow moving storms. Any path on our boat that the energy can take to neutralize this potential is good, the more the better including bonding anything to a common plate, and jumper cables if you have time and aren’t doing anything else. I would not include any thru hull fittings as part of the under water grid. They are isolated under water and don’t add a lot of surface area underwater. If something is the only path to ground for the beast, then you’re going to be the conductor to ground, a tree, house, golfer sailboat. Then the bonding will hopefully carry the energy to ground without damage to the boat or persons on board. Don’t get between the beast and ground, like unplugging an antenna, you then become the conductor to ground. We’ve all heard the stories about thru hulls being blown out in lighting hits, which is why my boat doesn’t have them bonded. My bonding includes all shrouds, and mast to a big dyna-plate.

This is only my opinion from listening to an old timer and licking a 9 volt battery.

 

[Tom Metzger]

I don't know how old you have to be to be an "old timer", but I do have lots of years behind me. Regardless, here are a couple of points to consider:

You equalize the charge around your mast by bleeding off electrons into the charged atmosphere from the masthead, antenna, or whatever is up there that is grounded and has sharp edges or points. This greatly reduces the likelihood of a stroke.

A Dynaplate is designed for a radio ground, not lightning. A lightning stroke will likely explode the Dynaplate leaving behind a hole in your hull. You are better off using copper bar stock. [Glyn - You should use bronze ]

YMMV

 

[westcoastcat]

Alright, a question for the experts here, I just purchased another boat ( not an Ericson, but I still own one so don't throw me off the site ) but this boat - non cored fiberglass hull, fin keel - lead, had a single very large grounding wire that went from the engine to a keel bolt, this wire had corroded off the keel bolt and per the surveyor this caused "galvanic corrosion" - basically the keel and hull around the keel blistered, the fairing material - cabosil on the keel and hull blistered. I never knew this could occur, anyone have any knowledge or experience with this. By the way another surveyor said this was a crock and that the fairing material on the keel was applied incorrectly - I don't know the boat is 26 years old, seems if it was installed incorrectly this would have occured prior to now.

 

[Loren Beach]

As I recall, my prior boat (built in the Great Lakes area) had a cable from the mast base to a keel bolt. Lots of lightning threat back there, I am told.

No corrosion at all, nor would there be, as long as the wire was not sitting in corrosive salt water inside the boat.

Keep the bilge dry, would be my take on this.

What is the keel made of? Lead has a lot less problems than cast iron, but either material can shed its fairing material if the metal is not correctly prepped before the fairing is applied. I know a ship wright and yard owner that used to have a very precise procedure to follow to get epoxy to bond securely to raw metal... and timing was very important.

No way to know what a former yard did or did not do right. Might be time now to redo the whole keel finish and fairing. And put in a new ground cable inside the boat while you're at it.

It depends on how much of a threat that lightning is in your sailing area, too. My boat was build in California and there was no ground installed there at all.


LB

edit: No, I do not believe that the ground cable or lack of one influenced the blistering. But that's just an opinion...