Lightning mitigation systems - South Florida

[RLB64]

New X4.9 being built. Carbon rig. Full B&G H5000 Electronics. Home port Miami. 

Scary scenario, right?  

Anyone have any real data or anecdotal evidence for lighting mitigation? 
Ion Diffuser? Sertec CMCE Sytem, 4/0 AWG hanging off the side!

I have contacted the ABYC (they set standards for boating industry). They have documentation on bonding minimums and lightning mitigation, E-11 and TE-4 respectively.

Any insight or discussion would be appreciated. 
 

Thanks 

Capt. Ron

 

[Rasputin22]

If it is gonna happen, then it is going to happen out there...

 

[Grande Mastere Dreade]

i was told a long time ago,   to go stand on deck with a 1 iron,  " 'cause not even god can hit a 1 iron... "

 

[slug zitski]

Every carbon mast I have worked with had a lightning conductor  ,, copper cable down the mast or the aluminum mainsail track used as a down conductor 

this conductor ends at a keel bolt 

at the mast head is a lighting rod 

does this system work ?  This is the Million dollar question 

somehow the lighting energy must get from masthead strike to the sea 

ask your mast builder for suggestions 

 

[SEC16518]

This is nonsense, lightning strikes with no resistance so it can pass through any medium. Anything with moving electrons (so not frozen at absolute zero) can conduct electricity if the voltage is high enough.

A heavy copper wire in carbon fiber mast?  What's the point of going with a lightweight mast then adding a heavy copper wire inside of it.

 

[RLB64]

If it is gonna happen, then it is going to happen out there...

Thanks Swab. 

 

[slug zitski]

New X4.9 being built. Carbon rig. Full B&G H5000 Electronics. Home port Miami. 

Scary scenario, right?  

Anyone have any real data or anecdotal evidence for lighting mitigation? 
Ion Diffuser? Sertec CMCE Sytem, 4/0 AWG hanging off the side!

I have contacted the ABYC (they set standards for boating industry). They have documentation on bonding minimums and lightning mitigation, E-11 and TE-4 respectively.

Any insight or discussion would be appreciated. 
 

Thanks 

Capt. Ron

And since it’s a xyacht , with  afiberglass enclosed keel , you have no seawater exit for the lightning  energy 

you should ask xyacht for a earth solution 

 

[Rasputin22]

    Seriously, that was sort of a welcome response to a newbie. Used to be a lot worse!

     I do understand your concern and am close to making a similar decision for a 50 catamaran with a carbon wing mast for Hawaii. I doubt the lightning threat in Hawaii would be as high as in your Florida location. Not many places have the potential for lightning quantity and danger. I used to work for Gold Coast Yachts who have probably built more USCG certified cats than anyone anywhere and we used to make our own needle point lightning rods by grinding a sharp point on a 3/8" SS threaded rod and connect that to a heavy gauge copper welding cable down to a copper sintered plate on the outside of one of the hulls. Those plates are often used for radio grounds (SSB?) and have a lot of surface area for their footprint. 

   That seemed to work until two of our boats got struck by the same squall line within a few minutes of each other. One was an earlier trimaran design which was one of GC's first licensed boats and it was in its slip in a marina in St Croix. That mast was an epoxy/plywood fold up mast similar to the Gougeon Bros early wingmast and the lightning seemed to run down the carbon uni tows that had been added at the top of the mast to stiffen the cantilevered portion of the mast above the mast hounds on the fractional rig. From there the strike seemed to prefer the SS headstay as a path and ran down to the headstay fitting at the bow. In addition it seemed that there was enough carbon derivative in what I remember as a Technora spinnaker halyard but the cap shrouds shared a good portion of the strike. I am not sure if that boat had the ground plate mentioned above but the result was dozens of pinholes in the outer skins of the nomex cored hull and the mast above the hounds looked like a cartoon shotgun that someone poked their finger in the barrel as it was fired.  The mast came back to our shop and I helped with the repair and post-mortem but it took months before the hull got dried out enough from drilled holes and paper towel wicks. Coast Guard would come out every couple months or so with a moisture meter until they deemed the hull dry enough to restore the tri's certification.

    The other boat was a GCY53 catamaran which was by far the workhorse of the daycharter fleet and it was out sailing with guests on board just south of St Thomas. It was a newer boat and had no core to be an issue and the rod, cable and ground were probably much better suited to the task but it was where the cable had to make two right angle turns to go from the mast base on CL out through the main cross beam and then a hard turn down into the hull to the grounding plate below the WL. That much electric current just didn't like the hard turns and blew out in several places. Enough juice got into the house electrical network to run aft to the helmstation where it blew out the instruments and such. The skipper got a pretty heavy shock holding onto the SS wheel and when his head cleared the first thing he noticed was his knuckles on one hand were bleeding and he couldn't under stand how he got that injury until someone noted that the shattered glass bezel on one of the instruments mounted on the bulkhead that the helm was bolted had some skin on it. Seems that the spasm of the electrical shock had made the skippers muscles tighten up and the back of his had a hit the instrument. The event scared the shit out of crew and guest alike but there were a few holes in the hull or hulls and were taking on some water. Those boats had outboard motors on sleds aft and those electrics must not have gotten disable so they were able to strike sail and motor back to their dock in a hurry.

     There was a lot of debate in the charter community and our own staff and we switched to the 'bottle brush' type of lightning 'charge disperser' that was just coming into use at that time. I think the idea that the 'bottle brush' bleeds off the electrical potential of the boat through the multitude of small wires without making the 'feeder spike' to the clouds above that lets the Big Bang follow back down to the boat. I think that debate still goes on. Keep us posted on what you decide...

Forespar Dissapator

 

[slug zitski]

With lightning you just never know 

your only choice is to use best practice and hope for the best 

Many boats use brushes , many use lightning rods 

what is certain is that you don’t want the lightning energy to flow down the carbon epoxy mast 

 

[Bowchow]

Where in MIami? Big chance you won't be the biggest stick around...

With that rig height I'd be more concerned about hurricane storage.. 

 

[AnotherSailor]

I recently read up about lightning mitigation and learned some interesting details.

Rasputin is right with the angles: electric current prefers to go straight, so if your system makes an angle it might jump to another "ground." Ideally it goes straight from the top of the mast to the keel. Some things I learned:

- If you do need to make an angle: 90 degrees is the absolute max with a radius of 2 feet. 

 - If the steel in your keel is covered (for example in fiberglass), ground plates can be used instead

- Not sure on the need of a copper wire. Carbon is a good conductor (better than stainless)

- there is a difference between salt and fresh water (you need better protection on fresh water)

- if you have a deck stepped mast, you need a wire from the bottom of the mast to the keel or ground plate (kind of a no-brainer, but again run this as straight as possible.

Then lastly, lightning does not always enter through the mast. It can hit the water near the boat and enter your systems that way. So in order to prevent damage:

- all metal parts need to be connected in straight lines (or as straight as possible): engine + shaft, rudder shaft, steering wheel, metal tanks, toe rail, and rigging

These were my notes from some research. It is not a complete list and I am happy to hear more thoughts as I am sometimes using a boat that is in a lightning area. If I purchased a new X4.9 I would hire a professional to take care of this. But it is never a bad idea to have some knowledge yourself. 

I am wondering if in Rasputin's story the strike did enter through the water, as opposed to the mast.

 

[AnotherSailor]

Let me correct myself on one point: carbon is by itself not a good conductor. So, yes ask the builder about that.

 

[slug zitski]

Let me correct myself on one point: carbon is by itself not a good conductor. So, yes ask the builder about that.

From a naval architect ….

“ Being an enthusiast of carbon fiber masts, I collect stories of lightning strikes on them. I have seen carbon masts turn to toast, and I have seen them survive. Those that get toasted are the ones with no lightning ground wire inside the mast. The easiest path for the lightning is through the mast laminate itself which is electrically conductive, being carbon. The fibers and the resin burn out, rendering the mast totally useless and unrepairable. Those that survive usually have a lightning ground wire inside the mast. The ground wire is an easier path for the lightning, having a lower resistance than the laminate. In these cases, the mast suffers no damage and goes on to sail another day.

I definitely recommend having a ground wire inside the mast and connected to an air terminal (solid round rod with a spherical top end) at the top of the mast and also to a grounding plate on the outside of the hull below the waterline.
 “

 

[AnotherSailor]

From a naval architect ….

“ Being an enthusiast of carbon fiber masts, I collect stories of lightning strikes on them. I have seen carbon masts turn to toast, and I have seen them survive. Those that get toasted are the ones with no lightning ground wire inside the mast. The easiest path for the lightning is through the mast laminate itself which is electrically conductive, being carbon. The fibers and the resin burn out, rendering the mast totally useless and unrepairable. Those that survive usually have a lightning ground wire inside the mast. The ground wire is an easier path for the lightning, having a lower resistance than the laminate. In these cases, the mast suffers no damage and goes on to sail another day.

I definitely recommend having a ground wire inside the mast and connected to an air terminal (solid round rod with a spherical top end) at the top of the mast and also to a grounding plate on the outside of the hull below the waterline.
 “

Thanks for that. Wouldn't damage result exactly from not being conductive enough? 

As far as I understand carbon fibre: it depends on how it is constructed.

I don't currently own a cf mast, so not my first worry, but it is that of the OP.

 

[slug zitski]

Thanks for that. Wouldn't damage result exactly from not being conductive enough? 

As far as I understand carbon fibre: it depends on how it is constructed.

I don't currently own a cf mast, so not my first worry, but it is that of the OP.

I’m not a lightning specialist 

I simply work on many boats and can observe “ best practice “ 

if you are in a region with many lightning strikes you should contact the insurance companies or a local surveyor to find out what works locally 

evidently boats in fresh water are very difficult to protect 

 

[kent_island_sailor]

FYI - fiberglass/carbon fiber airplanes can be destroyed by a lightning hit. To be certified for IFR, which involved thunderstorms some days, the plane must have a metal mess embedded to conduct lighting currents. This system passes lightning tests run by the FAA.

A carbon mast with a heavy conductor would *probably* be OK as long as the lighting hits the top where the terminal is. If the conductor was inside the mast and lighting burrowed in from the side, not so much.

This website is interesting: http://www.marinelightning.com/Siedarc.htm

Mast builders might want to look at this:

https://www.compositesworld.com/articles/lightning-strike-protection-for-composite-structures

IMHO the biggest issue is NDT, if the mast is not obviously damaged, how can you be sure it is not damaged at all?

 

[slug zitski]

FYI - fiberglass/carbon fiber airplanes can be destroyed by a lightning hit. To be certified for IFR, which involved thunderstorms some days, the plane must have a metal mess embedded to conduct lighting currents. This system passes lightning tests run by the FAA.

A carbon mast with a heavy conductor would *probably* be OK as long as the lighting hits the top where the terminal is. If the conductor was inside the mast and lighting burrowed in from the side, not so much.

This website is interesting: http://www.marinelightning.com/Siedarc.htm

Mast builders might want to look at this:

https://www.compositesworld.com/articles/lightning-strike-protection-for-composite-structures

IMHO the biggest issue is NDT, if the mast is not obviously damaged, how can you be sure it is not damaged at all?

They use ultra sound to survey carbon masts, structures 

when the resin fails, or disbonds ,  the ultrasound senses this  change in density of the laminate  

these tools are used by specialist surveyors 

I see this company on many carbon surveys 

https://www.marineresults.com/survey/

 

[nota]

tall buildings help about the only good point to condo's or office buildings near water

we lived aboard in dinner key anchorage and watched the storms roll in with strikes on the builds

regular event but hits on boat masts were very very rare so rare I can't remember any

useless data but about 300 boats with alloy masts pre carbon era from the clubs the marina and those anchored out over more then 20 years time in a very stormy high strike area but ringed by high rize buildings

 

[Zonker]

Bottle brush - better for toilets. You won't be to create enough ions unless it's the size of a beach ball.

Carbon masts - yes a grounding conductor is vital. I wonder if mast builders should study what aircraft do with copper mesh. I think it's just under a thin skin of e-glass to carry the arc on the surface and not get into the laminate.

This website is interesting: http://www.marinelightning.com/Siedarc.htm

Run by the only researcher who has devoted much of his career to lightning hitting boats. Expensive but probably the most rigorous in terms of what might work. He's been in business now for several years so probably has more results to show if his system works.

Catamaran grounding path: Make a hole in the bridgedeck just fwd or aft of the main beam. Glass in a GRP tube. Have the cable go straight down into the water with a grounding plate you lower down during a storm. Leave it in the water when the boat is unoccupied. That is what did. I knew lightning no like the 90 degree turns. The Siedarc folks now have this option. I was ahead of the science!