To Bond or NOT to Bond

[Anonymous 121765]

I know I will get alot of flack on this subject however, I can only relate to what I have learned & experienced the last twenty years.

I just read an article in Boat US Seaworthy (July, 2014 issue) magazine on "Below the waterline wisdom" by Steve D'Antonio covering bonding systems on boats. Steve seems to be very knowledgeable on bonding theories but, I have to disagree somewhat from what I have experienced over my twenty years. His article was about bonding components on a boat. This was to cover stray current, electrolysis & lightening protection.

I live on the left coast of Florida, you know, the lightening capital of the REAL world. Twenty years ago, a lightening strike bounced off the building close to me & hit my masthead. It burned out my Average Wind Indicator (AWI) & down to my VHF. So, I did my own background investigation first in lightning protection & this eventually took me to ship component bonding. I started with the USCG Lightning Cone of Protection info & from there it led me to bonding theories. When in a lightning storm, I turn off my electronics. I don't want a path to ground.

As for a bonded boat & lightning protection, I found a scientific article covering two new million dollar YACHTS with the latest in bonding systems that sunk as a result of a lightning strike. The bonding system was properly installed & all wires led to an anode in the bilge. There was a lightning strike on both NEW yachts & both sank.

The reason they sunk, was both had anodes in the lower section of the bilge & covered somewhat with water. When lightning did strike, the bonding system worked as it was designed to & channeled the strike directly to the anode. However, because the anode was in bilge water, the strike instantly vaporized the bilge water building up pressure which BLEW the thru-hull fittings out of the hulls. Both million dollar yachts sank, right there at the dock.

So, I read on & the more I read, the more I believed that lightning protection is not a guarantee. I now have no light green bonding wires attached anywhere on my boat. I had one, but it was attached to my fuel tank. You only need this when fueling for protection against static electricity. I have an alligator clip on my bonding wire & only clip this to my fuel tank tang when fueling. I also have alot of boats near me running systems 24/7 when a few years ago I was getting electrolysis that was attacking my pedestal. I disconnected all bonding, repaired the pedestal & have not had a problem since. I'm in a small bayou with alot of boats running systems.

Another problem I have observed with a bonding system is that this system is a two-way street. Most systems tie into an anode then to a ground on your engine ultimately passing thru your shaft to the water. But, what happens if you are around boats with systems running 24/7 & you are in a small bayou? The stray current fills this area up & guess what, up your shaft, thru your components causing electrolysis & galvanic corrosion.

My friend Luther moved his boat to such a place. Within a year his two aluminum fuel tanks started to leak. After great costs, they were removed & replaced with exact customized tanks. The removed tanks had the bonding connection & both tanks had holes in the center tank bottoms. When he installed the new tanks, I told him what I had read about bonding problems & that maybe he might want to think before attaching the bonding wires.
He decided to connect them & in less than a year & a half later, had both tanks leaking again. Guess where, center tank bottom.

To get a better grasp of this, check out the Galvanic chart:
https://www.google.com/search?q=met...9A4OayATZwILYDQ&ved=0CB4QsAQ&biw=1106&bih=514

Aluminum I feel suffers first, followed by dissimilar metals such as copper & brass connected to stainless.

I fully know I'm gonna take some hits on this, but this has been my experience to date. I know that what I have seen has merit, but each to their own I guess.

CR

 

[victorhoisington]

For me lightning is not my biggest worry. My boat was hit 4 years ago where a fender was rubbing the hull during one of our dry thunderstorms. Blew a hole, that ended up the size of a dinner plate, from the top of the fender into the boat on the kitchen side and back out at the bottom of the fender, about 2" above the waterline.

The interesting thing is, didn't touch the electronics but, the bag of chips in the kitchen was exploded across the cabin. I'll admit I've done only a little research but haven't seen anything that is fool proof. My neighbor has a lightning disbursment attachement at the top of the mast, grounded to the back stay and drags a frayed wire in the water as he sails. he's never been struck, so it works for him. My limited research says lighting is the most unpredictable of weather events and no amount of preparation will garauntee success.

So given what I know, I've decided I have no control and so won't get too worried about it. If you worry a lot about lighting, have fun bonding and grounding. You'll feel better and worry less, or like me, stand on the deck during a storm and watch the lighting. I love the view, but only hold onto the wooden hand rails during a storm.

 

[Benny17441]

The best protection against lighting strikes is INSURANCE. Fortunately boating has proved to be safer than golfing in this area. The majority of strikes on boats happen at the docks or near shore. There is something to be said about getting seaway in a storm both to avoid a lee shore and to reduce the incidence of lightning strikes. I do not trust bonding to re-direct the awesome forces of lightning so I would rather not attract it by making a lame path hoping it will follow it. I hear more about strikes with casualties to power boats than I hear about sailboats; perhaps the cone of protection is real.

 

[Crazy Dave Condon]

Not sure why but I always told my customers never moor close to land with a lot of pine trees.

 

[Anonymous 121765]

Dave,

I believe here in Florida, most fatalities from lightening are on a beach or under/near trees. Why you may ask, for one, trees are grounded. Beaches, I don't why.

Do you know that when you see a cloud to ground lightening strike that lasts 1-2 seconds & bright as the sun? A surprising fact is while looking like a big wide lightening bolt, they are no larger than the diameter of a silver dollar. It's the punch they pack that gives the illusion.

Here are some links on lightning facts:

http://hyperphysics.phy-astr.gsu.edu/hbase/electric/lightning2.html

http://www.weatherimagery.com/blog/lightning-facts/

CR

 

[Chris Patterson]

Lightning is 53000 degrees. The sun is 12,500,000

 

[capta]

Several years back I was reading about a company that builds a lightning protection system. They apparently installed it on a couple of new builds and both were hit almost immediately by lightning. Perhaps there was no damage, but it sure seemed their system attracted the hits.
I can't imagine an anode in the hull would conduct the lightning without causing severe damage to the hull around it. Often I've seen anodes hung over the side with alligator clips to the upper shrouds, but again, I can't imagine that they (or the internal bonding wires on most small craft) would carry the load, unless the clips and wire were huge (which they never are).
The one strike I took in the Keys only affected the 110 volt equipment that wasn't running (the ac unit, TV and fridge that were running were fine, but the other ac unit, water heater and generator were destroyed), so turning off the equipment may not be much help. As mentioned, perhaps insurance is the only reasonable defense. I think it's like fishing lures; whatever we think will work, makes us feel better, but neither the fish nor the lightning really care.

 

[DougMc]

Companies sell lighting protection systems to make money. No insurance asks for them. I believe in no bonding so that you will limit tiggl currents that seem to attract lightning.

 

[All U Get]

Lightning is 53000 degrees. The sun is 12,500,000

It's not the heat, it's the humidity.

All U Get

 

[Maine Sail]

Companies sell lighting protection systems to make money. No insurance asks for them. I believe in no bonding so that you will limit tiggl currents that seem to attract lightning.

There is no such thing as "lightning protection", meaning to prevent a strike..


The only good data we have suggests that non-bonded boats are struck slightly more than bonded boats... The idea behind lightning bonding is not to prevent a strike, you simply can't do that, it is to minimize hull damage and hopefully minimize side flashes in the cabin.. Bonded boats with good mast to keel or mast to lightning ground do also suffer slightly less hull damage.

 

[Skipper]

Mine is bonded from the chain plates to the thru hulls to the engine. I only figured it was to reduce corrosion on the whole boat, with the shaft anode protecting all. I Also hang a zinc grouper off the back stay, which prolongs the shaft anode.
I wouldn't think that those bonding wires would hold a lightning charge.
Although the mast base is bolted to the keel. I don't know if that would actually help.
Last, I think the reason more lighting statistically hits harbored boats is that most boats are in the harbor.

 

[Chris Patterson]

I've always been under the opinion that lightning protection was to spare the occupants, not the boat..

 

[Anonymous 121765]

What I have read, no breakers, fuses or isolators are immune to lightning strikes. The lightning volt/amperage will arc-pass these before they burn out.

Lightning protection is a matter of personal preference. Which is right is still up for discussion. I gotta tell ya, that a big direct hit is just that......a big direct hit.

CR

 

[Davidasailor26]

I saw a statement in a lightning thread a little while back that made a lot of sense to me - the electricity went through a mile of air to get to your boat; the extra few millimeters of open circuit or blown fuse probably won't help much. Stories like the potato chip bag being blown open without damaging electronics just reinforce the idea that lightning strikes and damage are unpredictable and pretty much uncontrollable, so to me it's not worth much time or effort to fight them.

 

[Mark Maulden]

When aircraft are hit, the airplane simply becomes part of the path whether it's cloud-cloud, or cloud-ground, or ground to cloud. When aircraft are hit there is an entry point and an exit point. The current flow can be 250,000a at 250,000V. A lot of energy. Between the moveable external control surfaces and the wing or fuselage are very beefy bonding straps. They are very short and they are as straight as possible. Lightning does not like to turn corners in a conductor. The magnetic fields induced by the high currents will try to straighten a curved conductor out and can break it. Aircraft bonding straps have been broken. So I do not put any credence to these protection systems that run wire all over the place. In a fiberglass boat, the best is as Maine describes. Mast/rigging to keeled other such ground pt. Also, the magnetic fields induced on ships wiring can cause voltages on the wiring that will damage electronics. Usually the power supply/data bus and or other interfaces. The straps on aircraft are heavy braid straps over an inch wide and shorter than six inches per hinge point.