My Hunter is a 77 30'. In Florida our lightning season is upon us. Do you have any recommendations for lightning protection specific to this boat. As far as I can tell the only grounding done so far (by the factory?) is a #12 wire from the mast step down to one of the keel bolts. I think the keel is lead filled and covered on the outside with fiberglass. If so, I wonder if this "grounding" is meaningful? Not a very good conductor into the water. Thanks, Henry
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SID JARVIS
LIGHTNING PROTECTION
While my boat was in Fort Lauderdale during a bad lightning period the delivery crew clamped battery cables to the shrouds and let them hang in the water. If your boat is going to be stationary for periods of time this might be helpful. The internal grounding in not sufficient. You might also try staying next to a boat with a taller mast. Good luck!
While my boat was in Fort Lauderdale during a bad lightning period the delivery crew clamped battery cables to the shrouds and let them hang in the water. If your boat is going to be stationary for periods of time this might be helpful. The internal grounding in not sufficient. You might also try staying next to a boat with a taller mast. Good luck!
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Bryan C.
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A.L. ("Jim") Willis Pres of ISLAND GIRL PROD.
More on electrical storms?
I'm very interested in this too: When I sailed out to HI in 94, there was one evening where I could see a lighting storm on the horizon where I was headed - the only thing for miles with a metal pole sticking out of the ocean. I researched this a bot and was told about the battery leads into the water bit. Apparently a lighting strike can blow all the electronics and even melt the bearings in the engine as the lighting exits via the prop! A also read about a "lighting dissapator:" that is like a wire brush attachment on the mast. Apprently this works (if it works) by allowing charge to leak slowly down rather than all at once. I had though myself of getting a large spike attached to battery lead all the way down to the water via the transom. Jim W
I'm very interested in this too: When I sailed out to HI in 94, there was one evening where I could see a lighting storm on the horizon where I was headed - the only thing for miles with a metal pole sticking out of the ocean. I researched this a bot and was told about the battery leads into the water bit. Apparently a lighting strike can blow all the electronics and even melt the bearings in the engine as the lighting exits via the prop! A also read about a "lighting dissapator:" that is like a wire brush attachment on the mast. Apprently this works (if it works) by allowing charge to leak slowly down rather than all at once. I had though myself of getting a large spike attached to battery lead all the way down to the water via the transom. Jim W
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John
Wire to nowhere!
I was cleaning and rebedding the mast step on our '85 H34 a few years ago. I pulled the step and in disconnecting that ground wire, and with barely a tug, the wire came out. It stuck about 5" into the deck and was cut off. As far as I know, this was the first time the step was ever removed. No protection at all!
I was cleaning and rebedding the mast step on our '85 H34 a few years ago. I pulled the step and in disconnecting that ground wire, and with barely a tug, the wire came out. It stuck about 5" into the deck and was cut off. As far as I know, this was the first time the step was ever removed. No protection at all!
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Phil Teter
ANSI/NFPA 78
IF you can find a copy of ANSI/NFPA 78 it has sailboat lightning protection information. IF you can't find it, Boatman's Motor Boating & Sailing Handbook (Revised Edition) by Hearst Marine Books has most of the same information. Good luck: Phil
IF you can find a copy of ANSI/NFPA 78 it has sailboat lightning protection information. IF you can't find it, Boatman's Motor Boating & Sailing Handbook (Revised Edition) by Hearst Marine Books has most of the same information. Good luck: Phil
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Jim Keller
Tallest Mast Aound
In September of 1998, I was the tallest mast around. Boat has a mast 63 feet above water. Took a hit while tied in slip with shore power connected. bolt apparently hit VHF antenna, which was blown away, then exited through shore power cord. Insurance is covering all but deductible to tune of $26,000. I have not heard of any foolproof way of protecting a boat. So make sure you have adequate insurance!
In September of 1998, I was the tallest mast around. Boat has a mast 63 feet above water. Took a hit while tied in slip with shore power connected. bolt apparently hit VHF antenna, which was blown away, then exited through shore power cord. Insurance is covering all but deductible to tune of $26,000. I have not heard of any foolproof way of protecting a boat. So make sure you have adequate insurance!
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Eric Lorgus
Lightning doesn't always strike the tallest object
As I understand it, lightning seeks the shortest path to ground. If a 60' and a 40' mast are within 100 yards of each other, lightning may strike the shorter mast, if it's the shortest path between ground and the point of origination of the charge. From what I've read (I'm certainly no expert), it seems the best protection is to give lightning a path to follow if it strikes your boat. That means wiring together the mast, compression post, shrouds, stays, engine block, and any other large masses of metal. These should all be connected to a metal plate of at least 12 square inches mounted under the boat. This is not a do-it-yourself project; it should be done by a qualified marine electrician. As for hanging chains or battery cables into the water from the shrouds, that might work if your mast, stays, and engine block are non-conductive. Otherwise, you may find part of the charge still seeking a path to ground on its own, and going through everything in its path.
As I understand it, lightning seeks the shortest path to ground. If a 60' and a 40' mast are within 100 yards of each other, lightning may strike the shorter mast, if it's the shortest path between ground and the point of origination of the charge. From what I've read (I'm certainly no expert), it seems the best protection is to give lightning a path to follow if it strikes your boat. That means wiring together the mast, compression post, shrouds, stays, engine block, and any other large masses of metal. These should all be connected to a metal plate of at least 12 square inches mounted under the boat. This is not a do-it-yourself project; it should be done by a qualified marine electrician. As for hanging chains or battery cables into the water from the shrouds, that might work if your mast, stays, and engine block are non-conductive. Otherwise, you may find part of the charge still seeking a path to ground on its own, and going through everything in its path.
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Rick Webb
Mind of it's own
I work with munitions and as you can imagine lightning protection is something we have studied. All of these responses make sense but the lightning is going to go wherever it wants to without regard for what protection you put out there. It may hit the taller mast or it may hit yours, it may even hit both. Best solution is to stay away from it, next to that is keep all the good Karma you can and to live right (whatever that is) lighting a candle may not hurt either. Most of all make sure your insurance is paid up all the time. Oh, and I personally would not go sailing with Lee Trevino nice guy but he seems to be a lightning magnet.
I work with munitions and as you can imagine lightning protection is something we have studied. All of these responses make sense but the lightning is going to go wherever it wants to without regard for what protection you put out there. It may hit the taller mast or it may hit yours, it may even hit both. Best solution is to stay away from it, next to that is keep all the good Karma you can and to live right (whatever that is) lighting a candle may not hurt either. Most of all make sure your insurance is paid up all the time. Oh, and I personally would not go sailing with Lee Trevino nice guy but he seems to be a lightning magnet.
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Edward Brennan
lightning primer
OK here goes. This forum does not really lend itself to a long primer but I've seen some good and not so good info out there. As a lightning detection and measurement engineer on the space shuttle program I get to record and measure about 15 strikes a year directly to my equipment. 1. 1. Lightning is inductive not resistive so "grounding" takes on a different term. The short answer is wide, flat cable with minumum bending tied directly to the keel. This will protect any individ
OK here goes. This forum does not really lend itself to a long primer but I've seen some good and not so good info out there. As a lightning detection and measurement engineer on the space shuttle program I get to record and measure about 15 strikes a year directly to my equipment. 1. 1. Lightning is inductive not resistive so "grounding" takes on a different term. The short answer is wide, flat cable with minumum bending tied directly to the keel. This will protect any individ
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Edward Brennan
lightning primer
OK here goes. This forum does not really lend itself to a long primer but I've seen some good and not so good info out there. As a lightning detection and measurement engineer on the space shuttle program I get to record and measure about 15 strikes a year directly to my equipment. 1. On any given day there is approximately 150 volts per meter of altitude in static charge. During a typical Florida storm lightning is triggered when this static charge reaches 5000 to 10,000 volts per meter. A 30 foot mast, properly "grounded" could be 100,000 volts higher in potential than the surrounding air at this height. 2. Lightning is inductive not resistive so "grounding" takes on a different term. The short answer is wide, flat cable with minumum bending tied directly to the keel. This will protect any individual from a direct flash but would certainly ring havoc with the electronics from induced fields or still cause death through side flashes. 3. Lightning is blind to it's ground environment until it reaches close to the ground so a tall mast won't trigger a flash. However, it's a good bet that the tallest mast has greater chance of being hit. 4. Brushes or dissipators effectively make the mast look smaller but it is still critical that proper grounding take place. 5. THe ANSI/NFPC 78 is great but also check out the ABYC standards ( boat insurance standards) For furhter reading try "Understanding Lightning" or "The Lightning Process" by Dr. Uman Sorry for dragging on....
OK here goes. This forum does not really lend itself to a long primer but I've seen some good and not so good info out there. As a lightning detection and measurement engineer on the space shuttle program I get to record and measure about 15 strikes a year directly to my equipment. 1. On any given day there is approximately 150 volts per meter of altitude in static charge. During a typical Florida storm lightning is triggered when this static charge reaches 5000 to 10,000 volts per meter. A 30 foot mast, properly "grounded" could be 100,000 volts higher in potential than the surrounding air at this height. 2. Lightning is inductive not resistive so "grounding" takes on a different term. The short answer is wide, flat cable with minumum bending tied directly to the keel. This will protect any individual from a direct flash but would certainly ring havoc with the electronics from induced fields or still cause death through side flashes. 3. Lightning is blind to it's ground environment until it reaches close to the ground so a tall mast won't trigger a flash. However, it's a good bet that the tallest mast has greater chance of being hit. 4. Brushes or dissipators effectively make the mast look smaller but it is still critical that proper grounding take place. 5. THe ANSI/NFPC 78 is great but also check out the ABYC standards ( boat insurance standards) For furhter reading try "Understanding Lightning" or "The Lightning Process" by Dr. Uman Sorry for dragging on....
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