Lightning

[Seminole Wind]

God always wins

I've read all the latest articles, ideas, and electrically engineered correct ways to deal with lightning; heck I even have a Meteorology degree. Plain truth is if it wants YOU, it will find YOU if YOU are near where it's looking. If you ground, then you attract, if you don't, then you attract less, but you also risk blowing a hole in your boat. My MacGregor 26C has been hit twice (with me on it) in 12 years along the Gulf Coast with very little more than EMP damage, so I"m lucky...really. The best advice is as many have mentioned, get away from the metal elements and go below if you can or lay low in the cockpit with in the pyramid of protection offered by the shrouds...better yet, pull up anchor sooner or check WX before you go out. An ounce of prevention is well...you know.

 

[moway]

Long Island Lightning Encounter

Have been in a number of "lightning" situations, but one stands out above all else...Sailing my Catalina 22 from New Rochelle, Long Island Sound, to dinner @ Port Washington; was ghosting into the outer harbor of Port Washington under full sail, when looking back over Manhattan, black swirling clouds were rushing over Laguardia & City Island, heading directly to Port Washington. Lightning was flashing throughout the immense storm front. Immediately started my 9.9 Merc & pointed the bow into the oncoming storm...My wife & Austrian guest climbed on the cabin top to lower the main as I furled the jib & steered. With the main half down, we were hit by a 4-foot wall of water and massive winds. The haulyard was wrapped once around the main & boom, keeping the sail onboard. We all held on as the entire boat was lifted out of the water, pivoted 180 degrees to starboard and smacked down again with the wind coming over the stern. I continued the starboard turn back into the wind...and again was picked up and thrown by the wind/waves 180 degrees. A larger boat (35' plus) close to shore did not see the storm soon enuf & was slammed flat onto the water, the mast sending up a massive spray. One more time, we continued our starboard piroette bringing the bow back into the wind and once more were literally heaved 180 degrees to starboard.All this time, in very confused waters and unbelievable wind, rain was pounding down and lightning was striking the water all around us. Seemed like dozens of lightning strikes narrowly missed our boat, but we were not hit (nothing was grounded as I trailered the boat & did not have grounding installed)We were able to get the main securely wrapped up with the haulyard to the boom. We turned the corner into the inner harbor and were blown quickly towards the Eastern beach covered with buildings on pilings (including our resturaunt). We could not stop the boat. Lightning continued to strike all around us. We headed directly into the large moorage area, hoping to grab someone's mooring bouy. My wife crawled on her belly to the bow; I laid the bow up to one bouy pennant ... she missed it & we were blown off; we did it again...again she missed to pennant & we were again blown off; the third time I circled, still in the heavy wind and pounding lightning (the waves had now stopped after rounding the point)we bowed up to our third bouy pennant. Christiane succeeded in grabbing the pennant, pulled up the mooring loop and slapped it over our bow cleat.Do one was wearing PFD, and no one panicked. We went below & had a stiff drink.We learned that 19 boats sank in that blow which continued over Long Island to the outer banks and into the Atlantic. Never did find out what hit us.Bruce MaynardH380 "Journey"Bellingham, Wa

 

[Bob W.]

"I'm A Believer--A Once of Protection"

Now that I live in Florida the lighting capital of the world, I realized the preventive measure I took years ago on board my Cat25 sailing out of Pensacola was a saviour. Worried about lighting chances I fabricated simple to obtain materials to make arresting rods(lines) by using heavy guage copper wire (same diameter as the power companies use for grounding their light poles)and some specialty clamps from the hardware store. The clamps are about 1-1/4" square made of two metal plates that squeeze together when two screws are tightened with a phillips screwdriver. At the first sign of any lighting in the area--visual or the smell of ozone--out come the lines. Two are attached to the port and starboard shrouds and the other to the back stay. I've put a fender washer on the ends of all the lines to create drag. The shroud drag lines are cut in length so as not to interfer with the outboard and are easy to stow. The aft drag line is the same length as the foward ones. Once all is attached, disconnect the antenna from the VHF. Throw open the inline switch to the batteries and everyone flat into their bunks. Start the motor to trolling speed (Sails all down of course) and go below deck and ride it out. My belief is that the humidity and rain one goes through in a sail boat with the rigging generating static electricity, makes one a likely for a strike. If your ever in a rain storm and can only see 10 to 15 feet in any direction, you'll know you did your best to protect crew and boat. Been there!!!

 

[Doug L]

Hull damage

I am about to purchase another boat (Lord willing!)and looked at a Hunter 26 that had been hit by lightening. Therre were a half dozen spots where the gel coat was blown off & repaired and & saw some minor delamination in the upper right side of the hull that I suspect was caused by the lightning. The owner said all the electronics and light fixtures had been replaced by his insurance company in additional to the gel coat repair, but I have to wonder if there was not additional damage to the hull. I have chosen to buy a different boat, at least in part because of the lightning strike.

 

[Terry]

On the other hand

Okay so you've tied everything together, shrouds, mast, keel etc. Does this protect you, or is it making your boat a better target than an un-grounded boat? They say lightning generally takes the path of least resistance.Sail On...Terry

 

[roger5034]

Bob

do you attach lighting protection cables to your mast and extend overboard ?

 

[Gord May]

For a good explanation of basic lightning protection principles, goto “Lightning

 

[Tim McCarty]

Well, after extensive reading on the subject...

I've found that there are no guarantees, although at this point, about the best thing I've heard is attached jumper cables. In order to be effective though, you would need to attach them, not only to every shroud, but also to the forstay, and backstay...that's a lot of cables (on my boat, it's 8-10). I've thought about buying heavy guage wire at the hardware store, and attaching clips to fasten to the stays. Good discussion topic.

 

[Steve]

Lightning strike

Two years ago. Patti, Grace (ship's cat) and I were making our approach to Ballantyne's Cove on Nova Scotia's north shore when the sky darkened substantially in a VERY short time. We brought in sail and prepared as best as we could for the squall we could see from about 9 miles. A bolt of lightning went from cloud-to-cloud right over the mast! It was right about then I remembered a quote from someone who said "If you see the lightning... it missed you!"

 

[Bob W.]

Roger--KC

Because the Cat 22 & 25's have stepped masts into a metal tabernacle with no grounding to the rest of the boat, I felt that I need only attach the clips/wires to the outer shrouds and back stay. I should mention the the clips were found in a speciality hardware store. They are 1-1/4" square, flat in the middle(one is threaded to receive the screw from the other half)and both halves have half moon shape grooves that match each other along their left and right sides to accept the wires that will be placed in them when the screws are tightened. I also added the fender washers(Note: get the largest diameter washer with the smallest center hole and flatten the wire to retain the washer)to create drag when in the water.

 

[Bob W.]

Tim--LaSalle,MI

"Tim--I'm laughing so hard because I can only visualize you running around hanging these wires, battery cables on your boat only to have the storm move right on by. Plus, you would need a suitcase to carry them around." I thought of using battery cables but I wanted full length bare wire as a conductor. In my case the diameter of the copper wire had to be less then the shroud diameter to provide a electrical "step-down" movement of any lightening strike. Also, the battery cables would not give me the extended length in the water and stood the chance of coming loose.

 

[Bob W.]

"Terry--Lake PendOrielle

"Grounded Versus Ungrounded Boat." Having lived in Chicago and slipped on the lake front, I've watched lightening strike the tall buildings up and down the lake front but no strikes on the many sail boats in the harbors or the street lights and wire trash containers at the curb. This said, lightening is looking for the path of least residence---the higher the better. For instance having been in the ocean oil rig/ship business hardly a storm day didn't go by that lightening didn't make a strike. If we, (You and I) were on our boats with guests in a lightening storm and I'm throwing copper wire in the water and your not, I sure within a couple of minutes my boat is going to look like I just escaped from Cuba with all the people on board--you included. "I CAN'T STOP LAUGHING -)"

 

[Joe Lupton on XTASEA]

"I think we were struck by lightning!"

My wife and I were cruising in the Chesapeake Bay about six years ago and we were looking for soft shell crabs at a small marina near Reedsville, VA. The sky was getting dark and thunder was getting louder as we departed the marina for our anchorage. Big raindrops were beginning to fall as we set the anchor and went below to ride it out. Withen a few minutes lightning was popping all around us as the rain came down in buckets. One strike seemed particully loud, and I told my wife, "that one was close!" It didn't take long before my wife asked, "what happened to the stereo?" which had been playing. The light was still on in the digital faceplate, but no audio came out. Not a good sign. I told her "I think were just got struck!"A few minutes later the storm had passed by and just as the rain had slowed to a drizzel, we heard someone on our stern hailing us. "Are you guys in there OK?" he asked. "You were hit by lightning!" They had been in a boat right behind us in the river and saw a strike to our masthead. A rescue vehicle even showed up on the bank behind a nearby resturant and they were calling us as well! WOW! some response! The results of our strike was surprising. We lost our VHF radio, the stereo, the onboard charger, and both the knot meter and depth sounder, both digital. I thought I had also lost the alternator, but it turned out to be OK. What really surprised me was the Raytheon 570 Loran, with an antenna attached to the stern rail, was not affected. It still works fine to this day! The VHF antenna was bent over in an inverted "U" shape from the instant heat, but it didn't seem to affect the co-ax cable which worked fine with a new antenna and VHF. Did I take any special measures prior to the storm? No. I did know the deck stepped mast had a heavy cable running from the deck plate to the forward keel bolt.Did it scare us? Other than the very close, loud noise it made, we had no way to know we had been struck other than the loss of our stereo.Joe

 

[Jim C.]

Saint Elmo's Fire

In a book about Magellan, the sailors see a blue halo around the mast and cross beam during thunderstorms. It was nothing more than static electricity. They called it Saint Elmo's Fire, thinking Saint Elmo was protecting them from lightening.I've never seen Saint Elmo's Fire on my Mac 26 D, is it possible an aluminum mast prevents it's forming?

 

[Terry]

Bob W. - Palm Coast Florida

Well I guess you figure you have a shorter mast than I. I work with equiptment day in day out that is grounded from lightning, some times it works and sometimes it doesn't. If you are grounding a boat keep the conductors short and large. Also, keep the conductors in as straight of path as possible as lightning will continue in a straight path if it encounters a sharp bend in a grounding conductor.  Anyone who says they won't get hit, but someone else will doesn't have a clue.Sail On...Terry

 

[Sue]

No Lightning Here

We're in Southern California - thunderstorms and lightning don't happen all that often here.

 

[Bob Weeks]

Cant make a decision when it comes to Lightning

Here is what happened to me and my Mac 25. When I bought the boat I docked it in a slip on a small creek that leads out to the Chesapeake Bay. After stepping the mast for the first time I noticed the VHF antenna was no good. I replaced the rf cable and antenna because it looked old and bad. Along with this I installed a battery master switch along with a accy switch bank, stereo, and a new mast light. A few weeks later we had a bad storm and to my surprise my boat was hit right at the dock! It blew the battery master switch right off the wall down below. Everything was fried. I replaced it all again only to be struck again later that summer at the dock! I thought that it could never happen twice. The next time I replaced everything chose to not put the VHF antenna on the mast because it seemed to me that this was the path to ground. I instead use a mag mount VHF and only pull it out when needed. I have heard two schools of thought. Cone of protection-Ground the mast straight from the top with at least an 8 Gauge wire as straight down as possible to the bottom of the hull and exit the boat at the keel or with a zinc or copper thru hull fitting. This is supposed to divert the strike out of the boat and protect the area around the mast.(Of course you should not touch anything metal) The second and my choice after being hit twice was to unground everything that was on the mast. All wiring is unplugged so that resistance to ground is higher. I also am very careful to watch the weather and I have been out in bad weather since without another strike. I am in the rf electronics business and I have seen many radio towers hit by lightning and they were always grounded well. Needless to say that it may save some equipment but I always had pleanty to fix or replace. Mother is going to win no matter what!!

 

[Moe16696]

First, do no harm...

There's considerable debate over whether grounding the mast makes it more likely to be struck by lightning. I won't join that debate, but do note that some who say it doesn't are in the business of selling lightning protection systems.If it does, the worst possible case is grounding it well enough to feed an attachment spark (which doesn't take much), but not well enough to carry the current of a direct hit and dissapate it into the water. How many masts would be unintentionally grounded worst case? A keel stepped mast may be grounded. Even a deck-stepped mast may be grounded through a less well conducting stainless steel compression post, especially if it's connected to a keel or centerboard hanger. Any light on the mast may ground it if it connects the 12VDC negative bus to the mast. A VHF whip grounds it, all the way up at the top, which some think may be worse. The 12VDC negative bus SHOULD be grounded and is on an inboard engine. But even with an outboard tilted up, it still may be in contact with the water at its transom mount. If the path to ground is through the 12VDC bus, doesn't it seem like any electronics connected to it could be damaged? And if shorepower equipped, doesn't that apply to everything connected to the 120VAC ground bus, which should be grounded at the 12VDC ground?Even if grounding doesn't make it more likely to be struck, is that because even a truely ungrounded mast is already so likely to be struck that it makes little difference? There are an awful lot of free electrons in an aluminum mast and boom. Does that leave enough positive ions at the top to create a large attachment spark when those electrons retreat to the bottom (as do those in the rigging)? The statistics seem to indicate if a sailboat IS hit, it's going to be on the mast.I don't pretend to know the answers to the above, but one thing I do know is that electricity doesn't take ONLY the path of least resistance. It takes as many paths as it can find, but the resistance does determine how much current flows through each. And when dealing with high voltage, sometimes it makes its own paths when it can't find enough with low enough resistance. I also question whether it is possible to provide a robust enough path with sufficiently low resistance to redirect the awesome power of a direct strike, especially in freshwater, since the ability to dissapate is part of that resistance.To date, we've done nothing about lightning protection. But doing nothing includes not mounting a mast top VHF antenna and not bonding the compression post to the centerboard hanger submerged in freshwater. I've rewired the lights on our mast and they don't bond the 12VDC negative to it. We keep them unplugged except at night.

 

[ex-admin]

Final results

Final results for the Quick Quiz ending August 28, 2005:My experience with lightning includes:45% Seeing lightning hit nearby24% Never seen it nearby and hope it stays that way18% Infrequent sightings13% My boat has taken a hit

 

[rfowlerhelen]

On my Javelin, the mast metal path leads very close to the keel. Any high voltage buildup of static or hit of lightning would surely arc thru to the water. (I hope)