Hello All!



I just purchased a 17' SuperCat (Yay me!) and still have quite a bit to learn - perhaps someone can help me with this latest debacle:



Everyone I have talked to, who store their sailboats in the same area I do, never take their masts down - The boat ramp is just 30-50ft away, and they claim it is simply too much trouble to lower the mast every time they bring the boat in.



These boats sit on there on trailers most of the week. My question is: How likely is it that lightning will hit these boats (I live in FL - We get a LOT of storms in the summer)? Has anyone had it happen to them? What type of damage did your boat recieve (if any)? Is there a way to protect the boat (other than taking the mast down)?



Any advice/comments are appreciated!



Sid sends

It would seem to me that there would be bigger boats with higher masts, flag poles, or even trees that would be more attractive "grounds" for lightening. But I'm not sure.



Look around the boat yard....LOTS of keel boat masts are "up" all the time. That said, if I didn't sail often I think I'd keep mine down if the parking space could accomodate it.



On the other hand THAT'S gonna be the first mast or rigging hardware stolen if anybody is so inclined. (But then when's the last time you saw somebody going down the road with a H17 mast on their roof without the boat?)



I saw Alan Alda's Science program on PBS visiting a world class lightening research center associated with the University there in Florida. Give em a call! LOL

I would think that if you stuck a grounding rod in the ground where you park your boat, and fashion a ground strap to connect your mast (and maybe the cross beams) to the rod whilst the boat is parked, you would have some measure of protection. To be truly protected, all the metal bits on your boat should be grounded together, but that may not be practical. But nothing is certain when dealing with lightning.



Grounding your mast would make it a lightning rod - meaning it would bleed potential off, making it less attractive to lightning, and giving it a path if it is hit anyway (although that path will most likely not be completely followed). The common misconception being that lightning rods attrack lightning - that's not their purpose. The keel boats in the marina are mostly protected this way - if the boat is built nice the mast is ground-strapped to the keel or other grounding plate on the hull. The other metal bits are also tied to the ground with ground straps. The end result is a supposed "cone of protection" that fans out about 45 degrees from the mast tip.



With my luck, I'd go through all this, and the lightning would hit the tree next to my boat, which would then fall over on it and crush it.

Keith,



I'm not certain that I agree that grounding your mast makes you less likely to attract lightning. Lightning is simply trying to reach ground and you're providing a closer and slightly more direct path by grounding the mast. True, lightning rods were not designed to attract lightning in that they were designed to give lightning an alternative, and more desirable, path to ground than through whatever structure they were placed on, but it is my understanding that they do attract more lightning strikes (i.e. why does it always work when lightning researchers send a small rocket into the sky with a copper wire attached to ground?)



I've also heard tale of improperly grounded monohulls being struck by lightning (while on the water either moored or underway) and the lightning splintering out at the base of the mast blasting countless tiny holes in the bottom of the hull causing the boats to take on water and/or sink.



Keep in mind however - I never proclaimed to always be right!

Sid,

The Hobie 16 I grew up with was named "Lightning Rod" for the reason, that as a teenager, I used to like to take the boat out just before a storm and try to hit the beach before I was overrun by lightning. Needless to say, I don't recommend doing that. Anyway one time I hit the beach, dropped my sails, and was going away from the boat when it got hit. (There were taller trees nearby, but no other boats) Luckily I was far enough away from the boat I didn't get fried, but was quite startled. The lightning must have gone staight through the mast and down the dolphin striker to ground as noted by the divot in the sand under the dolphin striker. I did not notice any residual damage to the boat. I have also seen lightning hit a mast that was down on a trailered boat, again no damage. Both of these boats had all aluminun masts. What I've concluded is don't be anywhere near a boat when there is lightning around, and lightning doesn't always hit the tallest thing around. I'd leave my mast up, so it's ready to go when the weather is nice, and pray to the gods that if lightning does hit my boat, no one is around when it happens.

Hey Sid, Do you want to spend more time sailing or more time rigging? The ones who leave their mast up probably want to sail more than rig. Besides, you are far more likely to have your boat blown over and damaged by a storm than to have it damaged by lightning, so if you want to lose sleep over something, that is the thing to think about! Even augurs put down near the trailer to secure the boat to usually fail in big storms that dump enough rain to soften the ground so that the augurs pull out. Get some insurance - it is very inexpensive and then you can get some sleep! Oh, did I mention the security issue? Make sure your insurance covers theft, too! :-)



Mike Fahle Toledo

Hi,

It seems counter-intuitive to me, too, Jake... but my grandfather, who was a civil engineer and a sailor, and a metalurgist, with a masters from RPI, told me the same tale as Keith. Alas, I was too young to fully grasp the "why" behind the "what"



Ed Norris

(...who still aint gonna hang around tall metal objects in thunderstorms)

The thing is, lightning is not necessarily looking for the tallest thing to hit. It's looking for something that it's attracted to due to a difference in electrical charge. The ground normally being negatively charged, clouds being both positive and negative. When the buildup of these charges is great enough, you get a spark between the two - lightning.



The idea of grounding things together provides a path for the lightning, but it also bleeds off charge build-up, helping to avoid the strike in the first place. The principle used is refered to as a "Faraday's Cage". In that it provides a conductive path for the lightning, you could argue that it indeed is supposed to attract lightning, and carry it away from what is in the cage. But again, the technique also bleeds off potential, thus helping to avert the strike.



Check out Chapman Piloting Seamanship and Small Boat Handling for a better description. No, I didn't write it... ;-)



The rockets: The rockets themselves are probably developing a negative charge as they go through the air - the cable provides a path for the strike - same idea, but in this case the rocket is intentionally building charge. A real world case - in 1986 an Atlas Centaur rocket was struck by lightning on launch. As the rocket entered the clouds, it got hit, destroying it and the payload. The strike continued through the rocket body to the ground near the launch pad. Same thing - the rocket built charge as it moved, the charge in the clouds couldn't resist...

I'm really not worried about theft - I keep the boat on an Air Force Base (Nowadays they are VERY particular about who comes in and what is going on around base).



Blowing over isn't really an issue either. Dry storage is constucted over an abandoned runway, so there are plenty of recessed cleats cemented into the concrete to tie the boat down to.



Bringing the mast up and putting it down takes less than 5 minutes. I think I am just going to take the mast down for the week, after I use it. If lightning hits one of the other boats in the area, I'll see what happens to it and go from there.



I don't like rigging more than anyone else, but most insurance policies have a deductable of ~$500 and run about $200 a year. If I have to replace a trampoline from a lightning hit, I'll still be in the red. I'll just throw that cash into savings - Just in case. ;-)



I appreciate everyone's help - It seems like taking the mast down is a prudent precaution to avoid electrical destruction.



Thanx!



Sid sends





SId sends

Summer lightning season is almost here, so I am reviving this thread because someone just put a question on the old forum asking whether it is safe to sail in lightning storms with a carbon mast.

Does anybody know what the relative conductivity is of carbon as compared to aluminum and to wood and to composite plastics like the Hobie comptip?

I just read somewhere that "carbon is a remarkably good conductor of electricity." That doesn't sound good.

I've been searching a bit but I can't find any information relating directly to epoxy / carbon fiber composite resistivity. However, I can tell you that it appears that the raw carbon fiber is more conductive than aluminum. I'm not sure how much effect the laminate layers and the epoxy would have.

My 10 cents:

We use carbon fiber conductors on our slip rings all the time as well has other composites. AL isn't all the great of a conductor and either is carbon fiber, but they both are used quite a lot. All of our rail systems are AL with a stainless steel cap.

There is no protection against lightning strikes if your mast is up. It is all chance. I have been sailing for 14 years and all 14 I have kept my boat with the mast up 90% of the sailing season and so has the rest of the fleet. We have never had a lightning strike, but sooner or later it will happen. Grounding a mast is a waste of sailing time. It is not a deturant. Even if a mast was grounded, the resistance in the AL will at the very least bend the heck out of it rendering it useless. If you want video on this in action, we have it from overload testing of the Las Vegas monorail.

Hobie CompTip's are a complete waste of time. They do have some performance bonuses, but making CompTips manditory for Hobie Class racing is laughable. Just another in a long line of money-making scemes from everyones friend HobieCat.

Bottom line, when it happens don't be around and just laugh it off when you see it the next day because your insurance will prob. buy you a new boat.

Flounder,

While I don't really care for a boat with a comp tip style mast from a performance standpoint it does seem to have some merit when you look at the statistics. It's not to prevent lightning strikes but rather to prevent the running it into overhead electrical wires. I'm a fairly intelligent being (by my own, and educational, account anyway) and twice now, I've come very close to running an all aluminum mast into power lines and realized so only after the fact. Hobie claims to have had no reported electrocutions associated with their boats and masts that have a comp tip. Again, while I think it's a little less flexible (no pun intended) with sail trim, it's hard to argue with this kind of statistic.

But i'd be choking if I rocked up to my boat to see this, (see image)

Well... if someone steps their mast by an overhead wire, a CompTip may not save them. The body of the main halyard pully is AL. The majority of the halyard is stainless steel along with the rigging. Halyard hits electrical source. Makes contact with the mast or other conductive peice of the boat and wah-laa. Common sense, not CompTips, save lives.

I think the CompTip is more of a saftey hazard. I have seen 7-10 Hobie masts fill up with water and turtle because of a poorly installed tip. If Hobie thought a little harder, they would have made a covering for the mast and replaced the halyard with an insulated one. There are non-conductive, commerical, spray-on coatings that work very well and are frequently used in crane power systems. One gallon will run Joe Nobody about $55 and will cover atleast 15 mast tips. How much does it cost to make a cast fiberglass tip?

Some of the things boat builders come up with and boat owners end up doing are just idiotic. I could go on (non-conductive hiking sticks, H16 design, rudder systems, mast rotators, etc...)

The entire reason we have a comptip is because of my friend Stanley's uncle who was electrocuted in NC due to a low-hanging wire.

Flounder,
A little history lesson.

The Comp-tip and non-conductive hiking sticks are the result of a consent
agreement reached when Hobie was sued by the family of a person who was
electrocuted by hitting a power line with his mast.
If Hobie Corp agreed to make the top portion of the mast out of a
non-conductive material, they cannot change to a mere non-conductive coating.
The Hobie 17, 18, & 20 have internal, non-conductive halyards.
The 16 halyard is half stainless and the stainless half is behind the
mast until the sail is raised. Most power lines are hit from the front.
I saw a guy stepping his mast and hit a power line.
When he realized what he had done, he said he understood about comp-tips.

I have seen plenty of all-aluminum masts leak and fill with water.

The so-called "performance advantages" of the Comp-tip are only advertising spin.

What is wrong with mast rotators?

Has a beach cat ever been hit by lightning while on the water? I cannot recall ever hearing of an incident.

Well, I would love to know what is non-conductive about a stainless steel wire and shackle. How will a non-conductive hiking stick help? If lightning strikes your boat and you are wet, you will get shocked no matter what type of stick is in your hand.

CompTip's allow for a small margin of saftey, but they are in no way safe. Common sense takes the place of engineering way to often.

Question: Why are Nacra's still made without non-conductive tips?