Lightning and what to do with it

[katiedobe]

I am newly arrived in the Yuctan area of Mexico and live on a large lake, 50 Km long by 15 Km wide about 40 miles as the crow flies from the Carribean ocean. So far dufing this winter we have a thunder and lighting filled squall blow in quickly across land and into the lake from the ocean about every other day. Being from the Pacific NW I am not used to the rapid deterioration in weather and am not able to predict if we will have a T-storm in the next hour or two when I depart the dock. Here is my question, I know how to dowse my sails and I have a small outboard and the waves never form very tall so capsizing is not a worry. What am I supposed to do about my large, 22 foot aluminum mast? I am not set up like some boats for quick lowerings for passing under bridges.

How do I protect from lightning when I am far from shore. I seem to remember that something about connecting a chain to the cable shroud and dangling that into the water and just hoping for the best. Ideally if I am close to shore I will anchor and swim to shore and get away from the boat and tall trees and enjoy the cooling shower. But what if I am out in the middle of the lake. These squalls move in quickly, and last only about 20 minutes, after which there is usually a fresh breeze,10t0 15 MPH, and lots of blue sky.
Any suggestions from tropical sailers?
Katiedobe

[katiedobe]

I am newly arrived in the Yuctan area of Mexico and live on a large lake, 50 Km long by 15 Km wide about 40 miles as the crow flies from the Carribean ocean. So far dufing this winter we have a thunder and lighting filled squall blow in quickly across land and into the lake from the ocean about every other day. Being from the Pacific NW I am not used to the rapid deterioration in weather and am not able to predict if we will have a T-storm in the next hour or two when I depart the dock. Here is my question, I know how to dowse my sails and I have a small outboard and the waves never form very tall so capsizing is not a worry. What am I supposed to do about my large, 22 foot aluminum mast? I am not set up like some boats for quick lowerings for passing under bridges.

How do I protect from lightning when I am far from shore. I seem to remember that something about connecting a chain to the cable shroud and dangling that into the water and just hoping for the best. Ideally if I am close to shore I will anchor and swim to shore and get away from the boat and tall trees and enjoy the cooling shower. But what if I am out in the middle of the lake. These squalls move in quickly, and last only about 20 minutes, after which there is usually a fresh breeze,10t0 15 MPH, and lots of blue sky.
Any suggestions from tropical sailers?
Katiedobe

[katiedobe]

I am newly arrived in the Yuctan area of Mexico and live on a large lake, 50 Km long by 15 Km wide about 40 miles as the crow flies from the Carribean ocean. So far dufing this winter we have a thunder and lighting filled squall blow in quickly across land and into the lake from the ocean about every other day. Being from the Pacific NW I am not used to the rapid deterioration in weather and am not able to predict if we will have a T-storm in the next hour or two when I depart the dock. Here is my question, I know how to dowse my sails and I have a small outboard and the waves never form very tall so capsizing is not a worry. What am I supposed to do about my large, 22 foot aluminum mast? I am not set up like some boats for quick lowerings for passing under bridges.

How do I protect from lightning when I am far from shore. I seem to remember that something about connecting a chain to the cable shroud and dangling that into the water and just hoping for the best. Ideally if I am close to shore I will anchor and swim to shore and get away from the boat and tall trees and enjoy the cooling shower. But what if I am out in the middle of the lake. These squalls move in quickly, and last only about 20 minutes, after which there is usually a fresh breeze,10t0 15 MPH, and lots of blue sky.
Any suggestions from tropical sailers?
Katiedobe

[Mrleft8]

Ground your mast. If it isn't already grounded, you can easilly ground it by wrapping a chain around it, and tossing the loose end (preferebly with a weight, like an anchor on it) into the water.

[Mrleft8]

Ground your mast. If it isn't already grounded, you can easilly ground it by wrapping a chain around it, and tossing the loose end (preferebly with a weight, like an anchor on it) into the water.

[Mrleft8]

Ground your mast. If it isn't already grounded, you can easilly ground it by wrapping a chain around it, and tossing the loose end (preferebly with a weight, like an anchor on it) into the water.

[Gary E]

I am not 100% sure that this will work 100% of the time BUT,

I KNOW IT WORKED ONCE.

Several of us fished out in the Atlantic Ocean in sportfishing boats. Storms can and do blow in at anytime.

So, what we did was run a heavy copper wire, I am talking 1/4 in Dia here, all the way up the base pole of the radio antenna and connect it to the ground plate mounted on the boats keel.

One day, Joe and his crew were not to far from me, maybe a mile or so when I heard him on the VHF say, "You see whutz commin?" ...umm, yeah, letz go home.

Home wuz 20 or so miles and the water was lumpy. As we both headed to the inlet several miles went by and all of a sudden KABOOM... Holy CRAP that was loud, but we kept on going. I looked over to Joe and seems he was lagging so I waited, then he started up and we continued on to the dock. Wasnt until we both tied up did I learn why he didnt answer the radio. He was hit by that ligntning and the it stopped both engines. He hit the starters and both engines came alive then he tried to use the radio but when he reached for the mic, it was in pieces all over flybridge deck.

So I know it worked ONCE.

[Gary E]

I am not 100% sure that this will work 100% of the time BUT,

I KNOW IT WORKED ONCE.

Several of us fished out in the Atlantic Ocean in sportfishing boats. Storms can and do blow in at anytime.

So, what we did was run a heavy copper wire, I am talking 1/4 in Dia here, all the way up the base pole of the radio antenna and connect it to the ground plate mounted on the boats keel.

One day, Joe and his crew were not to far from me, maybe a mile or so when I heard him on the VHF say, "You see whutz commin?" ...umm, yeah, letz go home.

Home wuz 20 or so miles and the water was lumpy. As we both headed to the inlet several miles went by and all of a sudden KABOOM... Holy CRAP that was loud, but we kept on going. I looked over to Joe and seems he was lagging so I waited, then he started up and we continued on to the dock. Wasnt until we both tied up did I learn why he didnt answer the radio. He was hit by that ligntning and the it stopped both engines. He hit the starters and both engines came alive then he tried to use the radio but when he reached for the mic, it was in pieces all over flybridge deck.

So I know it worked ONCE.

[Tristan]

Am no expert, and you need to heed what a really knowledgable person can tell you, but I don't think chain is the complete answer. I'd say you need to ground with a piece of VERY heavy copper wire, that sticks above your mast a foot or so, with the upper end sharpened. The other end of the wire should run down a shroud and into the water where it is fastened to a copper plate, or be securely fastened to the mast which, in turn, must be linked to a heavy bronze through-hull fitting that is fastened to a fairly large piece of copper that us permanently fastened to the hull. If you opt for a down the shroud wire, you can SECURELY clamp the "in the water" section of wire with it's copper plate when lightening threatens. Otherwise the copper lightening rod, mast and through the hull might be the best idea. Again, these are only vague guidelines that I recall from the dim distant past and by all means, consult an expert. Lightening can jump all over is there are loose connections (and chains are not the best conductors) or large chunks of metal to attract it away from a guided path.

[ 07-25-2005, 05:15 PM: Message edited by: Tristan ]

[Tristan]

Am no expert, and you need to heed what a really knowledgable person can tell you, but I don't think chain is the complete answer. I'd say you need to ground with a piece of VERY heavy copper wire, that sticks above your mast a foot or so, with the upper end sharpened. The other end of the wire should run down a shroud and into the water where it is fastened to a copper plate, or be securely fastened to the mast which, in turn, must be linked to a heavy bronze through-hull fitting that is fastened to a fairly large piece of copper that us permanently fastened to the hull. If you opt for a down the shroud wire, you can SECURELY clamp the "in the water" section of wire with it's copper plate when lightening threatens. Otherwise the copper lightening rod, mast and through the hull might be the best idea. Again, these are only vague guidelines that I recall from the dim distant past and by all means, consult an expert. Lightening can jump all over is there are loose connections (and chains are not the best conductors) or large chunks of metal to attract it away from a guided path.

[ 07-25-2005, 05:15 PM: Message edited by: Tristan ]

[Gary E]

I am not 100% sure that this will work 100% of the time BUT,

I KNOW IT WORKED ONCE.

Several of us fished out in the Atlantic Ocean in sportfishing boats. Storms can and do blow in at anytime.

So, what we did was run a heavy copper wire, I am talking 1/4 in Dia here, all the way up the base pole of the radio antenna and connect it to the ground plate mounted on the boats keel.

One day, Joe and his crew were not to far from me, maybe a mile or so when I heard him on the VHF say, "You see whutz commin?" ...umm, yeah, letz go home.

Home wuz 20 or so miles and the water was lumpy. As we both headed to the inlet several miles went by and all of a sudden KABOOM... Holy CRAP that was loud, but we kept on going. I looked over to Joe and seems he was lagging so I waited, then he started up and we continued on to the dock. Wasnt until we both tied up did I learn why he didnt answer the radio. He was hit by that ligntning and the it stopped both engines. He hit the starters and both engines came alive then he tried to use the radio but when he reached for the mic, it was in pieces all over flybridge deck.

So I know it worked ONCE.

[Tristan]

Am no expert, and you need to heed what a really knowledgable person can tell you, but I don't think chain is the complete answer. I'd say you need to ground with a piece of VERY heavy copper wire, that sticks above your mast a foot or so, with the upper end sharpened. The other end of the wire should run down a shroud and into the water where it is fastened to a copper plate, or be securely fastened to the mast which, in turn, must be linked to a heavy bronze through-hull fitting that is fastened to a fairly large piece of copper that us permanently fastened to the hull. If you opt for a down the shroud wire, you can SECURELY clamp the "in the water" section of wire with it's copper plate when lightening threatens. Otherwise the copper lightening rod, mast and through the hull might be the best idea. Again, these are only vague guidelines that I recall from the dim distant past and by all means, consult an expert. Lightening can jump all over is there are loose connections (and chains are not the best conductors) or large chunks of metal to attract it away from a guided path.

[ 07-25-2005, 05:15 PM: Message edited by: Tristan ]

[Ian McColgin]

Given how high lightning forms, a 22' mast will not "pull" lightening very far.

Lightening seeks the best route between cloud and earth charges. To some extent, high spots are smaller and thus concentrate the charge, so the effect of a lonely hill top with a silo on it attracting multiple lightning strikes is common.

Golfers are often fooled by heights, and God hates the silly cloths they wear anyway, so they too are subject to lightening strikes.

A small sailboat is actually not very likely to be struck, but it never hurts to prepare.

I preferr hanging a couple fathoms of very heavy copper wire one from each upper shroud. Wrap the wire on above the turnbuckle.

Do not ground the back stay. Also do not sit right between the back stay and the rudder post, just incase there's any flashing.

Do completely disconnect any radio antenna and anything else you can off the mast. Even with a good path to earth through the stays and heavy wire, you can get a huge charge inside that will blow most everything.

You might also consider a very huge but super short - like an inch from the mast - ground strap and outside big ground plate, but I prefer the hanging wire approach.

I preferr to sail through a squall. Assuming no close lee shore, run off under jib alone or even bare pole. Depending on the sloop, you may well be able to hold five or so points off the wind under jib alone, so you need not just go downwind.

G'luck

[Ian McColgin]

Given how high lightning forms, a 22' mast will not "pull" lightening very far.

Lightening seeks the best route between cloud and earth charges. To some extent, high spots are smaller and thus concentrate the charge, so the effect of a lonely hill top with a silo on it attracting multiple lightning strikes is common.

Golfers are often fooled by heights, and God hates the silly cloths they wear anyway, so they too are subject to lightening strikes.

A small sailboat is actually not very likely to be struck, but it never hurts to prepare.

I preferr hanging a couple fathoms of very heavy copper wire one from each upper shroud. Wrap the wire on above the turnbuckle.

Do not ground the back stay. Also do not sit right between the back stay and the rudder post, just incase there's any flashing.

Do completely disconnect any radio antenna and anything else you can off the mast. Even with a good path to earth through the stays and heavy wire, you can get a huge charge inside that will blow most everything.

You might also consider a very huge but super short - like an inch from the mast - ground strap and outside big ground plate, but I prefer the hanging wire approach.

I preferr to sail through a squall. Assuming no close lee shore, run off under jib alone or even bare pole. Depending on the sloop, you may well be able to hold five or so points off the wind under jib alone, so you need not just go downwind.

G'luck

[Ian McColgin]

Given how high lightning forms, a 22' mast will not "pull" lightening very far.

Lightening seeks the best route between cloud and earth charges. To some extent, high spots are smaller and thus concentrate the charge, so the effect of a lonely hill top with a silo on it attracting multiple lightning strikes is common.

Golfers are often fooled by heights, and God hates the silly cloths they wear anyway, so they too are subject to lightening strikes.

A small sailboat is actually not very likely to be struck, but it never hurts to prepare.

I preferr hanging a couple fathoms of very heavy copper wire one from each upper shroud. Wrap the wire on above the turnbuckle.

Do not ground the back stay. Also do not sit right between the back stay and the rudder post, just incase there's any flashing.

Do completely disconnect any radio antenna and anything else you can off the mast. Even with a good path to earth through the stays and heavy wire, you can get a huge charge inside that will blow most everything.

You might also consider a very huge but super short - like an inch from the mast - ground strap and outside big ground plate, but I prefer the hanging wire approach.

I preferr to sail through a squall. Assuming no close lee shore, run off under jib alone or even bare pole. Depending on the sloop, you may well be able to hold five or so points off the wind under jib alone, so you need not just go downwind.

G'luck

[Ken Hutchins]

Ian good info, the only thing that should be considered is use braided multi strand non insulated wire, not a big solid wire. the electricity will flow along the surface of the wire not thru the middle and the combined surface of many strands are greater then a single wire. All building lightning rod systems use loosely braided multi strand wire.
The other thought on this is that a good properly grounded system with pointed rods will tend to dissipate the electrical charge before it builds up to the dangerous lightning potential, which will help to minimise the number of hits.

[Ken Hutchins]

Ian good info, the only thing that should be considered is use braided multi strand non insulated wire, not a big solid wire. the electricity will flow along the surface of the wire not thru the middle and the combined surface of many strands are greater then a single wire. All building lightning rod systems use loosely braided multi strand wire.
The other thought on this is that a good properly grounded system with pointed rods will tend to dissipate the electrical charge before it builds up to the dangerous lightning potential, which will help to minimise the number of hits.

[Ken Hutchins]

Ian good info, the only thing that should be considered is use braided multi strand non insulated wire, not a big solid wire. the electricity will flow along the surface of the wire not thru the middle and the combined surface of many strands are greater then a single wire. All building lightning rod systems use loosely braided multi strand wire.
The other thought on this is that a good properly grounded system with pointed rods will tend to dissipate the electrical charge before it builds up to the dangerous lightning potential, which will help to minimise the number of hits.

[kc8pql]

Here's a link to the best information out there on lightning and boats, written by an electrical engineer at Florida State. Lightning Protection of Boats (http://www.thomson.ece.ufl.edu/lightning/)

[kc8pql]

Here's a link to the best information out there on lightning and boats, written by an electrical engineer at Florida State. Lightning Protection of Boats (http://www.thomson.ece.ufl.edu/lightning/)

[kc8pql]

Here's a link to the best information out there on lightning and boats, written by an electrical engineer at Florida State. Lightning Protection of Boats (http://www.thomson.ece.ufl.edu/lightning/)

[PaulC]

"Being from the Pacific NW I am not used to the rapid deterioration in weather and am not able to predict if we will have a T-storm in the next hour or two when I depart the dock."

Do you have a barometer? It won't tell you to the hour, but it will give you a pretty good indication of what is coming. Be sure to read the booklet that comes with it.

[PaulC]

"Being from the Pacific NW I am not used to the rapid deterioration in weather and am not able to predict if we will have a T-storm in the next hour or two when I depart the dock."

Do you have a barometer? It won't tell you to the hour, but it will give you a pretty good indication of what is coming. Be sure to read the booklet that comes with it.

[PaulC]

"Being from the Pacific NW I am not used to the rapid deterioration in weather and am not able to predict if we will have a T-storm in the next hour or two when I depart the dock."

Do you have a barometer? It won't tell you to the hour, but it will give you a pretty good indication of what is coming. Be sure to read the booklet that comes with it.

[katiedobe]

Thanks for all the great info. I knew I could count on you folks.

Here is a little more info. I have a plywood, glued and taped seam sloop, 17 feet long. The mast is an aluminum one from Dwyer mast Co with no back stay or upper shrouds or spreaders. Simple side stays and fore stay. No built in radio antannea, handhold VHF only. My wife is the only person who listens to me, as no coast guard or police presence on the lake. I do have some #4 copper wire, stranded.

Two questions.
Does the whole lenght of the copper wire need to be bare or only the top few feet?

My mast is stepped on top of the deck as this was designed as a trailer sailer. I do have two 1/4" steel plates bolted to both sides of my 12" deep keel, no centerboard, as ballast. Can I just attach the copper wire to this plate?

I will get a barometer it may help. I have not observed one, it would be interesting to see if there is a sudden change or just the same low reading all day long. Often the storms pass 20 miles away on the horizon. Or I may see it off in the distance and then it moves away from me.

Any suggestions for a good set of Themometer, humidity, and Barometer to buy. I am now in the US for 4 weeks and can carry some things back.
Katiedobe

[katiedobe]

Thanks for all the great info. I knew I could count on you folks.

Here is a little more info. I have a plywood, glued and taped seam sloop, 17 feet long. The mast is an aluminum one from Dwyer mast Co with no back stay or upper shrouds or spreaders. Simple side stays and fore stay. No built in radio antannea, handhold VHF only. My wife is the only person who listens to me, as no coast guard or police presence on the lake. I do have some #4 copper wire, stranded.

Two questions.
Does the whole lenght of the copper wire need to be bare or only the top few feet?

My mast is stepped on top of the deck as this was designed as a trailer sailer. I do have two 1/4" steel plates bolted to both sides of my 12" deep keel, no centerboard, as ballast. Can I just attach the copper wire to this plate?

I will get a barometer it may help. I have not observed one, it would be interesting to see if there is a sudden change or just the same low reading all day long. Often the storms pass 20 miles away on the horizon. Or I may see it off in the distance and then it moves away from me.

Any suggestions for a good set of Themometer, humidity, and Barometer to buy. I am now in the US for 4 weeks and can carry some things back.
Katiedobe

[katiedobe]

Thanks for all the great info. I knew I could count on you folks.

Here is a little more info. I have a plywood, glued and taped seam sloop, 17 feet long. The mast is an aluminum one from Dwyer mast Co with no back stay or upper shrouds or spreaders. Simple side stays and fore stay. No built in radio antannea, handhold VHF only. My wife is the only person who listens to me, as no coast guard or police presence on the lake. I do have some #4 copper wire, stranded.

Two questions.
Does the whole lenght of the copper wire need to be bare or only the top few feet?

My mast is stepped on top of the deck as this was designed as a trailer sailer. I do have two 1/4" steel plates bolted to both sides of my 12" deep keel, no centerboard, as ballast. Can I just attach the copper wire to this plate?

I will get a barometer it may help. I have not observed one, it would be interesting to see if there is a sudden change or just the same low reading all day long. Often the storms pass 20 miles away on the horizon. Or I may see it off in the distance and then it moves away from me.

Any suggestions for a good set of Themometer, humidity, and Barometer to buy. I am now in the US for 4 weeks and can carry some things back.
Katiedobe

[katiedobe]

I just visited the link regarding lighting posted by kc8pql. Everyone should read the pamphlet and if you have time watch the video.

All my questions have been answered. Now I just need to find stips of copper or aluminum in the Yucatan. That I can do easily enough.

Thanks.

[katiedobe]

I just visited the link regarding lighting posted by kc8pql. Everyone should read the pamphlet and if you have time watch the video.

All my questions have been answered. Now I just need to find stips of copper or aluminum in the Yucatan. That I can do easily enough.

Thanks.

[katiedobe]

I just visited the link regarding lighting posted by kc8pql. Everyone should read the pamphlet and if you have time watch the video.

All my questions have been answered. Now I just need to find stips of copper or aluminum in the Yucatan. That I can do easily enough.

Thanks.

[Ken Hutchins]

To prevent electroylsis problems I would use aluminum wire on the mast and use an aluminum to copper wire connector somewhere away from the mast, these connectors are available at large electrical suppliers or from lightning rod suppliers.

[Ken Hutchins]

To prevent electroylsis problems I would use aluminum wire on the mast and use an aluminum to copper wire connector somewhere away from the mast, these connectors are available at large electrical suppliers or from lightning rod suppliers.

[Ken Hutchins]

To prevent electroylsis problems I would use aluminum wire on the mast and use an aluminum to copper wire connector somewhere away from the mast, these connectors are available at large electrical suppliers or from lightning rod suppliers.

[Ian McColgin]

I'd go with the dangle off the shrouds approach as you really have to work hard to make a good bond mast base to mast step and then step down to plate bolts (especially if they are just bolted to each other through the keel) and even then steel is not such a wonderful ground plate.

Braided wire strapping is readily available, more commonly uninsulated. Any insulation where it's in the air does not matter either way, but you want it uninsulated under water and, of course, contacting the stay.

Thunder storms are intensly local and a baramoter will not give that great a warning. Often they come in squall lines and you can see ranks of thunderstorms stalking you.

If you're on the edge and can't see clearly the storm's path, Bayes-Ballots Law (sp approx) is just a restatement that these are anti-clockwise rotating storms. Face the wind. Stick your right hand straight out to your side. Point with your index finger. That's the direction of the storm's center.

If you can determine the storm's track - likely west to east but there are more exceptions than examples - consider the storm's direction as its zero degrees. Try to get to the storm's 270 - 360 side where you can sail out of it on a broad port reach and the wind intensity is lessend by the storm's movement.

If you're on the 0 - 90 side, the broad port reach will hold you in the storm forever. A port beat might get you through if you and the boat are tough enough. Try a starboard beat, close reach or heave-to.

(Antipodal friends note that this is Northern Hemisphere stuff.)

Prayer also helps.

[Ian McColgin]

I'd go with the dangle off the shrouds approach as you really have to work hard to make a good bond mast base to mast step and then step down to plate bolts (especially if they are just bolted to each other through the keel) and even then steel is not such a wonderful ground plate.

Braided wire strapping is readily available, more commonly uninsulated. Any insulation where it's in the air does not matter either way, but you want it uninsulated under water and, of course, contacting the stay.

Thunder storms are intensly local and a baramoter will not give that great a warning. Often they come in squall lines and you can see ranks of thunderstorms stalking you.

If you're on the edge and can't see clearly the storm's path, Bayes-Ballots Law (sp approx) is just a restatement that these are anti-clockwise rotating storms. Face the wind. Stick your right hand straight out to your side. Point with your index finger. That's the direction of the storm's center.

If you can determine the storm's track - likely west to east but there are more exceptions than examples - consider the storm's direction as its zero degrees. Try to get to the storm's 270 - 360 side where you can sail out of it on a broad port reach and the wind intensity is lessend by the storm's movement.

If you're on the 0 - 90 side, the broad port reach will hold you in the storm forever. A port beat might get you through if you and the boat are tough enough. Try a starboard beat, close reach or heave-to.

(Antipodal friends note that this is Northern Hemisphere stuff.)

Prayer also helps.

[Ian McColgin]

I'd go with the dangle off the shrouds approach as you really have to work hard to make a good bond mast base to mast step and then step down to plate bolts (especially if they are just bolted to each other through the keel) and even then steel is not such a wonderful ground plate.

Braided wire strapping is readily available, more commonly uninsulated. Any insulation where it's in the air does not matter either way, but you want it uninsulated under water and, of course, contacting the stay.

Thunder storms are intensly local and a baramoter will not give that great a warning. Often they come in squall lines and you can see ranks of thunderstorms stalking you.

If you're on the edge and can't see clearly the storm's path, Bayes-Ballots Law (sp approx) is just a restatement that these are anti-clockwise rotating storms. Face the wind. Stick your right hand straight out to your side. Point with your index finger. That's the direction of the storm's center.

If you can determine the storm's track - likely west to east but there are more exceptions than examples - consider the storm's direction as its zero degrees. Try to get to the storm's 270 - 360 side where you can sail out of it on a broad port reach and the wind intensity is lessend by the storm's movement.

If you're on the 0 - 90 side, the broad port reach will hold you in the storm forever. A port beat might get you through if you and the boat are tough enough. Try a starboard beat, close reach or heave-to.

(Antipodal friends note that this is Northern Hemisphere stuff.)

Prayer also helps.

[Tom Robb]

You don't need instruments to see a thunder storm.
Cumulus clowds building way high and the top blowing off in an anvil shape are thunder storms. Next you get a cold/cool sudden wind blowing from the storm's downdraft. Ya wanna be reefed by then :rolleyes: or better yet off the lake.
You'll hear the thunder before you see strikes. Time from boom to flash yields proximity - about 6 seconds/mile, IRRC. Thousands get killed by lightning each year so paranoia is reasonably well founded.
Enjoy the show anyway :D

[ 07-26-2005, 01:30 PM: Message edited by: Tom Robb ]

[Tom Robb]

You don't need instruments to see a thunder storm.
Cumulus clowds building way high and the top blowing off in an anvil shape are thunder storms. Next you get a cold/cool sudden wind blowing from the storm's downdraft. Ya wanna be reefed by then :rolleyes: or better yet off the lake.
You'll hear the thunder before you see strikes. Time from boom to flash yields proximity - about 6 seconds/mile, IRRC. Thousands get killed by lightning each year so paranoia is reasonably well founded.
Enjoy the show anyway :D

[ 07-26-2005, 01:30 PM: Message edited by: Tom Robb ]

[Tom Robb]

You don't need instruments to see a thunder storm.
Cumulus clowds building way high and the top blowing off in an anvil shape are thunder storms. Next you get a cold/cool sudden wind blowing from the storm's downdraft. Ya wanna be reefed by then :rolleyes: or better yet off the lake.
You'll hear the thunder before you see strikes. Time from boom to flash yields proximity - about 6 seconds/mile, IRRC. Thousands get killed by lightning each year so paranoia is reasonably well founded.
Enjoy the show anyway :D

[ 07-26-2005, 01:30 PM: Message edited by: Tom Robb ]

[Ric_Bergstrom]

AM radio will snap every time lightning strikes.

Well before you are in range.

About the cheapest lightning detector you can buy.

[Ric_Bergstrom]

AM radio will snap every time lightning strikes.

Well before you are in range.

About the cheapest lightning detector you can buy.

[Ric_Bergstrom]

AM radio will snap every time lightning strikes.

Well before you are in range.

About the cheapest lightning detector you can buy.

[Ken Hutchins]

A customer was in the local marine supply emporium yesterday, buying a bunch of stuff to replace what was destroyed by a lightning strike, everything from the wind direction indicator, to epoxy to fix fried f$#%$#%$# and even o rings for deck fill plugs. So I asked him if he had a lightning ground system on the boat :D of course the answer was no. :rolleyes:

[Ken Hutchins]

A customer was in the local marine supply emporium yesterday, buying a bunch of stuff to replace what was destroyed by a lightning strike, everything from the wind direction indicator, to epoxy to fix fried f$#%$#%$# and even o rings for deck fill plugs. So I asked him if he had a lightning ground system on the boat :D of course the answer was no. :rolleyes:

[Ken Hutchins]

A customer was in the local marine supply emporium yesterday, buying a bunch of stuff to replace what was destroyed by a lightning strike, everything from the wind direction indicator, to epoxy to fix fried f$#%$#%$# and even o rings for deck fill plugs. So I asked him if he had a lightning ground system on the boat :D of course the answer was no. :rolleyes:

[Tom Lathrop]

Originally posted by Tom Robb:
Thousands get killed by lightning each year so paranoia is reasonably well founded.
:D Tom,

The National Weather Service records show that an average of 73 people die each year in the USA from lightning strikes. Not a trivial number but a bit less than thousands. It is more than tornadoes and some other natural disasters but well short of paranoia inducement.

The best scientific studies show that nothing short of a metal enclosure will prevent all human damage on a boat struck by lightning. The referenced articles from Florida State are probably the best information available. The advice is fairly straightforward but proper execution on a given boat is often extremely difficult to achieve.

Manufacturers don't seem to make any provision whatever for lightning protection and I don't think the USCG makes any requirements on them. Does anyone know of any boats that come from the factory with lightning protection. :confused:

One recomendation often overlooked and even erroneously advised by some experts is to run bonding wire down the inside of the hull to the underwater terminal plate. This is wrong since strikes to the water through the hull then become more attractive.

Lightning current is DC but the wavefront is so steep (nanoseconds) that the current looks like broadband AC. This is why it shows up on a AM radio at all frequencies. This also why it likes stranded wire (more surface area where AC current likes to flow) and why it can blow through the hull (a capacitor) so easily and why sharp bends (high series inductive impedance) are to be avoided. In other words, a sharp bend in a bonding wire just inside the hull and below the waterline is an invitation for a hole in the hull.

An alligator clip on a stay and chain to the water make be of some use but misses all the rules. The mast terminal protectors (bottle brushes) are claimed to protect the boat by dissipating the energy before a strike can form but I don't think any of the evidence supports that. As the articles say, the best protection is a good (straight as possible) connection bewteen the mast top to the water under the hull. Also keep your body as far away as possible from making a connection between any two metalic points in the boat or metalic points and the water.

Lightning is not magic but it often acts like it. Its a bit like genes in your offspring, only somewhat predictable. I have worked on high voltage and, even in the lab, it is hard to completely control the outcome of an experiment.

As for the underwater ground terminal, don't be fooled by the claims of the porus copper "Dynaplate". These are no better than a solid copper bar of equal size. They may even be worse in a lightning strike since they might explode by steam generated inside the porus structure by the current. A metal keel is the best bet (other than a metal hull) and a copper plate outside the hull and as close to below the mast as possible.

I assume no responsibility for anything in the above. I'm sorry this was so long but I lack the time to make it shorter.

[Tom Lathrop]

Originally posted by Tom Robb:
Thousands get killed by lightning each year so paranoia is reasonably well founded.
:D Tom,

The National Weather Service records show that an average of 73 people die each year in the USA from lightning strikes. Not a trivial number but a bit less than thousands. It is more than tornadoes and some other natural disasters but well short of paranoia inducement.

The best scientific studies show that nothing short of a metal enclosure will prevent all human damage on a boat struck by lightning. The referenced articles from Florida State are probably the best information available. The advice is fairly straightforward but proper execution on a given boat is often extremely difficult to achieve.

Manufacturers don't seem to make any provision whatever for lightning protection and I don't think the USCG makes any requirements on them. Does anyone know of any boats that come from the factory with lightning protection. :confused:

One recomendation often overlooked and even erroneously advised by some experts is to run bonding wire down the inside of the hull to the underwater terminal plate. This is wrong since strikes to the water through the hull then become more attractive.

Lightning current is DC but the wavefront is so steep (nanoseconds) that the current looks like broadband AC. This is why it shows up on a AM radio at all frequencies. This also why it likes stranded wire (more surface area where AC current likes to flow) and why it can blow through the hull (a capacitor) so easily and why sharp bends (high series inductive impedance) are to be avoided. In other words, a sharp bend in a bonding wire just inside the hull and below the waterline is an invitation for a hole in the hull.

An alligator clip on a stay and chain to the water make be of some use but misses all the rules. The mast terminal protectors (bottle brushes) are claimed to protect the boat by dissipating the energy before a strike can form but I don't think any of the evidence supports that. As the articles say, the best protection is a good (straight as possible) connection bewteen the mast top to the water under the hull. Also keep your body as far away as possible from making a connection between any two metalic points in the boat or metalic points and the water.

Lightning is not magic but it often acts like it. Its a bit like genes in your offspring, only somewhat predictable. I have worked on high voltage and, even in the lab, it is hard to completely control the outcome of an experiment.

As for the underwater ground terminal, don't be fooled by the claims of the porus copper "Dynaplate". These are no better than a solid copper bar of equal size. They may even be worse in a lightning strike since they might explode by steam generated inside the porus structure by the current. A metal keel is the best bet (other than a metal hull) and a copper plate outside the hull and as close to below the mast as possible.

I assume no responsibility for anything in the above. I'm sorry this was so long but I lack the time to make it shorter.

[Tom Lathrop]

Originally posted by Tom Robb:
Thousands get killed by lightning each year so paranoia is reasonably well founded.
:D Tom,

The National Weather Service records show that an average of 73 people die each year in the USA from lightning strikes. Not a trivial number but a bit less than thousands. It is more than tornadoes and some other natural disasters but well short of paranoia inducement.

The best scientific studies show that nothing short of a metal enclosure will prevent all human damage on a boat struck by lightning. The referenced articles from Florida State are probably the best information available. The advice is fairly straightforward but proper execution on a given boat is often extremely difficult to achieve.

Manufacturers don't seem to make any provision whatever for lightning protection and I don't think the USCG makes any requirements on them. Does anyone know of any boats that come from the factory with lightning protection. :confused:

One recomendation often overlooked and even erroneously advised by some experts is to run bonding wire down the inside of the hull to the underwater terminal plate. This is wrong since strikes to the water through the hull then become more attractive.

Lightning current is DC but the wavefront is so steep (nanoseconds) that the current looks like broadband AC. This is why it shows up on a AM radio at all frequencies. This also why it likes stranded wire (more surface area where AC current likes to flow) and why it can blow through the hull (a capacitor) so easily and why sharp bends (high series inductive impedance) are to be avoided. In other words, a sharp bend in a bonding wire just inside the hull and below the waterline is an invitation for a hole in the hull.

An alligator clip on a stay and chain to the water make be of some use but misses all the rules. The mast terminal protectors (bottle brushes) are claimed to protect the boat by dissipating the energy before a strike can form but I don't think any of the evidence supports that. As the articles say, the best protection is a good (straight as possible) connection bewteen the mast top to the water under the hull. Also keep your body as far away as possible from making a connection between any two metalic points in the boat or metalic points and the water.

Lightning is not magic but it often acts like it. Its a bit like genes in your offspring, only somewhat predictable. I have worked on high voltage and, even in the lab, it is hard to completely control the outcome of an experiment.

As for the underwater ground terminal, don't be fooled by the claims of the porus copper "Dynaplate". These are no better than a solid copper bar of equal size. They may even be worse in a lightning strike since they might explode by steam generated inside the porus structure by the current. A metal keel is the best bet (other than a metal hull) and a copper plate outside the hull and as close to below the mast as possible.

I assume no responsibility for anything in the above. I'm sorry this was so long but I lack the time to make it shorter.

[Mike DeHart]

I did the math one day and calculated very close to 5 seconds per mile between flash and BOOM.

[Mike DeHart]

I did the math one day and calculated very close to 5 seconds per mile between flash and BOOM.

[Mike DeHart]

I did the math one day and calculated very close to 5 seconds per mile between flash and BOOM.

[Tom Robb]

Tom, the statistic that I recall, (given my creeping CRS) was some thousands. Perhaps I'm confusing it with persons hit by lightning. The number, IIRC, was a comparison with winning the lottery - way easier to get hit by lightning :eek:
Your number may be correct. I have no documentation.

[ 08-02-2005, 03:56 PM: Message edited by: Tom Robb ]

[Tom Robb]

Tom, the statistic that I recall, (given my creeping CRS) was some thousands. Perhaps I'm confusing it with persons hit by lightning. The number, IIRC, was a comparison with winning the lottery - way easier to get hit by lightning :eek:
Your number may be correct. I have no documentation.

[ 08-02-2005, 03:56 PM: Message edited by: Tom Robb ]

[Tom Robb]

Tom, the statistic that I recall, (given my creeping CRS) was some thousands. Perhaps I'm confusing it with persons hit by lightning. The number, IIRC, was a comparison with winning the lottery - way easier to get hit by lightning :eek:
Your number may be correct. I have no documentation.

[ 08-02-2005, 03:56 PM: Message edited by: Tom Robb ]

[ssor]

Lightening strikes where it will when it will. I have seen it strike the ground in a pasture a hundred yards from a white oak. I have seen it strike a short poplar tree in the valley with hundreds of taller trees around and up the hill.I was discussing this with a friend and she said that in Marathon, Florida there was one of boats with all the proper lightening gear attached that was struck three times in one season. The companies that sell homeowners insurance will not discount your premiums because you have installed lightening protection. So where does this leave you? I don't know of any boats in our marina that have lightening protection devises installed, and have not heard of a boat being damaged by lightening in the thiry plus years I have been here, a couple of barns and a house on the next street but no boats.

[ssor]

Lightening strikes where it will when it will. I have seen it strike the ground in a pasture a hundred yards from a white oak. I have seen it strike a short poplar tree in the valley with hundreds of taller trees around and up the hill.I was discussing this with a friend and she said that in Marathon, Florida there was one of boats with all the proper lightening gear attached that was struck three times in one season. The companies that sell homeowners insurance will not discount your premiums because you have installed lightening protection. So where does this leave you? I don't know of any boats in our marina that have lightening protection devises installed, and have not heard of a boat being damaged by lightening in the thiry plus years I have been here, a couple of barns and a house on the next street but no boats.

[ssor]

Lightening strikes where it will when it will. I have seen it strike the ground in a pasture a hundred yards from a white oak. I have seen it strike a short poplar tree in the valley with hundreds of taller trees around and up the hill.I was discussing this with a friend and she said that in Marathon, Florida there was one of boats with all the proper lightening gear attached that was struck three times in one season. The companies that sell homeowners insurance will not discount your premiums because you have installed lightening protection. So where does this leave you? I don't know of any boats in our marina that have lightening protection devises installed, and have not heard of a boat being damaged by lightening in the thiry plus years I have been here, a couple of barns and a house on the next street but no boats.

[Tom Lathrop]

Tom,

Statistics can be tough to nail down since they often are derived from different sources with different criteria and/or over different time periods. One source I looked at is:

http://www.lightningsafety.com/nlsi_lls/fatalities_us.html

This gives an even lower number of annual deaths as a bit over 58 per year.

Having lived most of my life in the lightning belt, I've had the opportunity to observe it up close more than anyone might like. One sailing friend was killed by lightning but not in a sailboat. It often does strange and unpredictable things. That is, unpredictable because we don't have complete information (or maybe complete understanding) of the instantaneous parameters when it occurs. It follows rigid physical laws and principles but, in any individual case, we are not able to apply these to predict the correct solution.

And statistics can lead us far astray sometimes. For instance, the number of males killed each year is 84% to 16% for females. Think about the stupid conclusions that could be given for that :rolleyes:

[Tom Lathrop]

Tom,

Statistics can be tough to nail down since they often are derived from different sources with different criteria and/or over different time periods. One source I looked at is:

http://www.lightningsafety.com/nlsi_lls/fatalities_us.html

This gives an even lower number of annual deaths as a bit over 58 per year.

Having lived most of my life in the lightning belt, I've had the opportunity to observe it up close more than anyone might like. One sailing friend was killed by lightning but not in a sailboat. It often does strange and unpredictable things. That is, unpredictable because we don't have complete information (or maybe complete understanding) of the instantaneous parameters when it occurs. It follows rigid physical laws and principles but, in any individual case, we are not able to apply these to predict the correct solution.

And statistics can lead us far astray sometimes. For instance, the number of males killed each year is 84% to 16% for females. Think about the stupid conclusions that could be given for that :rolleyes:

[Tom Lathrop]

Tom,

Statistics can be tough to nail down since they often are derived from different sources with different criteria and/or over different time periods. One source I looked at is:

http://www.lightningsafety.com/nlsi_lls/fatalities_us.html

This gives an even lower number of annual deaths as a bit over 58 per year.

Having lived most of my life in the lightning belt, I've had the opportunity to observe it up close more than anyone might like. One sailing friend was killed by lightning but not in a sailboat. It often does strange and unpredictable things. That is, unpredictable because we don't have complete information (or maybe complete understanding) of the instantaneous parameters when it occurs. It follows rigid physical laws and principles but, in any individual case, we are not able to apply these to predict the correct solution.

And statistics can lead us far astray sometimes. For instance, the number of males killed each year is 84% to 16% for females. Think about the stupid conclusions that could be given for that :rolleyes:

[ssor]

Originally posted by Tom Lathrop:
Tom,

And statistics can lead us far astray sometimes. For instance, the number of males killed each year is 84% to 16% for females. Think about the stupid conclusions that could be given for that :rolleyes: Is that because they have lightening rods? :rolleyes:

[ssor]

Originally posted by Tom Lathrop:
Tom,

And statistics can lead us far astray sometimes. For instance, the number of males killed each year is 84% to 16% for females. Think about the stupid conclusions that could be given for that :rolleyes: Is that because they have lightening rods? :rolleyes:

[ssor]

Originally posted by Tom Lathrop:
Tom,

And statistics can lead us far astray sometimes. For instance, the number of males killed each year is 84% to 16% for females. Think about the stupid conclusions that could be given for that :rolleyes: Is that because they have lightening rods? :rolleyes:

[Tom Lathrop]

Originally posted by ssor:
</font><blockquote>quote:</font><hr />Originally posted by Tom Lathrop:
Tom,

And statistics can lead us far astray sometimes. For instance, the number of males killed each year is 84% to 16% for females. Think about the stupid conclusions that could be given for that :rolleyes: Is that because they have lightening rods? :rolleyes: </font>[/QUOTE]Grounding rods perhaps. Or maybe because they are enlightened. :D

Statistics also show that the worse state for being killed ,on a per capita basis, is Wyoming and that the Rockies, from Mexico to Canada are bad news for lightning kills. So males on horseback riding in the mountains or high plains is much more risky than sailing in the coastal US.

I knew that :D

And please, there is no "e" in lightning.

[Tom Lathrop]

Originally posted by ssor:
</font><blockquote>quote:</font><hr />Originally posted by Tom Lathrop:
Tom,

And statistics can lead us far astray sometimes. For instance, the number of males killed each year is 84% to 16% for females. Think about the stupid conclusions that could be given for that :rolleyes: Is that because they have lightening rods? :rolleyes: </font>[/QUOTE]Grounding rods perhaps. Or maybe because they are enlightened. :D

Statistics also show that the worse state for being killed ,on a per capita basis, is Wyoming and that the Rockies, from Mexico to Canada are bad news for lightning kills. So males on horseback riding in the mountains or high plains is much more risky than sailing in the coastal US.

I knew that :D

And please, there is no "e" in lightning.

[Tom Lathrop]

Originally posted by ssor:
</font><blockquote>quote:</font><hr />Originally posted by Tom Lathrop:
Tom,

And statistics can lead us far astray sometimes. For instance, the number of males killed each year is 84% to 16% for females. Think about the stupid conclusions that could be given for that :rolleyes: Is that because they have lightening rods? :rolleyes: </font>[/QUOTE]Grounding rods perhaps. Or maybe because they are enlightened. :D

Statistics also show that the worse state for being killed ,on a per capita basis, is Wyoming and that the Rockies, from Mexico to Canada are bad news for lightning kills. So males on horseback riding in the mountains or high plains is much more risky than sailing in the coastal US.

I knew that :D

And please, there is no "e" in lightning.

[ssor]

And please, there is no "e" in lightning.[/QB]So noted. Thanks.
Ross

[ssor]

And please, there is no "e" in lightning.[/QB]So noted. Thanks.
Ross

[ssor]

And please, there is no "e" in lightning.[/QB]So noted. Thanks.
Ross