lightning protection - Page 3 - SailNet Community

   Search Sailnet:

 forums  store  


Quick Menu
Forums           
Articles          
Galleries        
Boat Reviews  
Classifieds     
Search SailNet 
Boat Search (new)

Shop the
SailNet Store
Anchor Locker
Boatbuilding & Repair
Charts
Clothing
Electrical
Electronics
Engine
Hatches and Portlights
Interior And Galley
Maintenance
Marine Electronics
Navigation
Other Items
Plumbing and Pumps
Rigging
Safety
Sailing Hardware
Trailer & Watersports
Clearance Items

Advertise Here






Go Back   SailNet Community > On Board > Gear & Maintenance
 Not a Member? 
  #21  
Old 08-21-2008
teshannon's Avatar
Senior Member
 
Join Date: Aug 2006
Location: Philadelphia
Posts: 2,713
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 11
teshannon has a spectacular aura about teshannon has a spectacular aura about teshannon has a spectacular aura about
The boat that got hit by lightning in my marina a few weeks ago had a grounding system. Maybe that's why they got hit. Most but not all of their electronics were fried. When the boat was hauled the thru hulls were fine but the grounding plate was still it's original color. I'm told it should have turned pink. I'm not sure if that means his grounding system was not wired propoerly but in any case the system, such as it was, did not help them much. I'm with SD, if you're happy with what you have leave it alone.
Reply With Quote Quick reply to this message Share with Facebook
  #22  
Old 08-21-2008
ASA and PSIA Instructor
 
Join Date: Apr 2000
Posts: 3,496
Thanks: 7
Thanked 19 Times in 19 Posts
Rep Power: 15
sailingfool will become famous soon enough
Quote:
Originally Posted by sailingdog View Post
..... However, there is evidence that grounded boats do get hit more often...
OK, I'll bite, can you reference us to the evidence that grounded boats are struck more often...I personally think that is an urban myth...
__________________
Certified...in several regards...
Reply With Quote Quick reply to this message Share with Facebook
  #23  
Old 08-22-2008
Classic30's Avatar
Once known as Hartley18
 
Join Date: Aug 2007
Location: Melbourne, Australia
Posts: 4,618
Thanks: 38
Thanked 54 Times in 54 Posts
Rep Power: 9
Classic30 will become famous soon enough Classic30 will become famous soon enough
Quote:
Originally Posted by sailingfool View Post
OK, I'll bite, can you reference us to the evidence that grounded boats are struck more often...I personally think that is an urban myth...
Maybe someone's done the research - maybe they haven't. At the end of the day, what matters is what happens to *your boat* when the clouds are overhead.

The truth is that lightning doesn't obey the laws of man. Grounding the boat is no guarantee it's going to come out unscathed - it's more of a "Mister Lightning please travel this way and don't hurt my pretty boat - thank you!" suggestion. Lightning does whatever it blooming likes.

If it helps, most countries have fairly comprehensive Lightning Protection standards (like AS/NZS 1768) which are reasonably easy to read and can go a long way to dispelling myths.

I'd suggest the first thing anyone worried about this should do is get a copy of the latest "thunder days" map for your area from the Met Bureau... and then make sure you park in a clear spot.
__________________
-
"Honestly, I don't know why seamen persist in getting wrecked in some of the outlandish places they do, when they can do it in a nice place like Fiji." -- John Caldwell, "Desperate Voyage"
Reply With Quote Quick reply to this message Share with Facebook
  #24  
Old 08-22-2008
hellosailor's Avatar
Senior Member
 
Join Date: Apr 2006
Posts: 10,884
Thanks: 2
Thanked 102 Times in 99 Posts
Rep Power: 10
hellosailor has a spectacular aura about hellosailor has a spectacular aura about
"Maybe someone's done the research "

No maybe about it, the folks who know how to deal with lightning are all in the broadcast engineering industry. You know, the guys who hold up the sign that says "TECHNICAL DIFFICULTIES, PLEASE STAND BY" on your TV?

Radio and television antenna towers are lightning magnets. Antenna towers are routinely over 1000 feet tall, out in the middle of nowhere, and built all of metal with metal guy cables. Some are closer to 1/4 mile tall. Then there are sites like the Empire State Building, which was capped with the broadcast antennas for most of the network anchors in NYC before the WTC was built with the new tower antenna on it. The Empire State gets hit by lightning something like 300 times a year--and it doesn't knock the stations off the air, or damage the building. (Except for some holes in the roof, literally.)

Those guys know that a good grounding path can carry the jillion volts and amps right down into the ground, without destroying the goodies alongside it. MOST of the time, anyway. Once in a while--a rare while--they still have to hold up those signs.[g]

Give lightning an express lane to travel in, and it usually will. Leave it to find its own path--and you're likely to take a lot of collateral damage. "Please travel this way" is a very good way to put it!
Reply With Quote Quick reply to this message Share with Facebook
  #25  
Old 08-22-2008
Seafire327's Avatar
Member
 
Join Date: Aug 2008
Location: Boston, Massachusetts
Posts: 43
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
Seafire327 is on a distinguished road
Quote:
Originally Posted by hellosailor View Post
"Maybe someone's done the research "

No maybe about it, the folks who know how to deal with lightning are all in the broadcast engineering industry. You know, the guys who hold up the sign that says "TECHNICAL DIFFICULTIES, PLEASE STAND BY" on your TV?

Radio and television antenna towers are lightning magnets. Antenna towers are routinely over 1000 feet tall, out in the middle of nowhere, and built all of metal with metal guy cables. Some are closer to 1/4 mile tall. Then there are sites like the Empire State Building, which was capped with the broadcast antennas for most of the network anchors in NYC before the WTC was built with the new tower antenna on it. The Empire State gets hit by lightning something like 300 times a year--and it doesn't knock the stations off the air, or damage the building. (Except for some holes in the roof, literally.)

Those guys know that a good grounding path can carry the jillion volts and amps right down into the ground, without destroying the goodies alongside it. MOST of the time, anyway. Once in a while--a rare while--they still have to hold up those signs.[g]

Give lightning an express lane to travel in, and it usually will. Leave it to find its own path--and you're likely to take a lot of collateral damage. "Please travel this way" is a very good way to put it!
I work for a radio station in Boston and in my time there (4+ years) we've never had a lightning strike knock us off the air. Now I know there is heavy duty grounding since the antenna is on top of the Prutential Tower, along with a lot of other stuff, but I'm not sure of the system in place. When our chief engineer gets back next week I'm going to rack his brain...

And one other interesting thing... Right outside my studio window is the 80 foot tower used to transmit our signal to the Pru and in al this wild weather we've had over the past 2 months, no hit. Not a good feeling sitting almost under the thing though....
__________________
'70 Columbia C26 Mk II - "Klydo"
Boston, Ma
Reply With Quote Quick reply to this message Share with Facebook
  #26  
Old 08-22-2008
arbarnhart's Avatar
Senior Member
 
Join Date: Jun 2007
Location: North Carolina
Posts: 761
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 8
arbarnhart is on a distinguished road
Quote:
Originally Posted by sailingfool View Post
OK, I'll bite, can you reference us to the evidence that grounded boats are struck more often...I personally think that is an urban myth...
The one I read referred to terrestrial insurance data with the bit about the farm tractors being hit far more (like orders of magnitude) than random chance would explain. But as someone pointed out to me earlier in this thread, I was a believer in a myth myself - tires don't insulate cars and trucks. I still have a hard time believing that a vehicle riding on largely rubber tires is solidly grounded.

That same report referred to a boat study which seemed to indicate that grounding didn't attract more strikes, but the author explained that away. His reasoning was that the owners only said the boat was grounded if it was explicitly wired to ground, but there were keel stepped boats who didn't claim to be grounded and pretty much any boat with an inboard and mast mounted electroics is grounded. EDIT - By "grounded" in in this context I mean providing a path to the ground, whether it is a proper one that attempts to avoid electronics or through the electronics burning up wires and jumping switches.
__________________
-Andy
Newport 17 - "Kohanna"
At sea Darwin's hypotheses is the final arbiter of right of way.

Last edited by arbarnhart; 08-22-2008 at 08:28 AM.
Reply With Quote Quick reply to this message Share with Facebook
  #27  
Old 08-22-2008
sailingdog's Avatar
Telstar 28
 
Join Date: Mar 2006
Location: New England
Posts: 43,290
Thanks: 0
Thanked 11 Times in 11 Posts
Rep Power: 13
sailingdog is just really nice sailingdog is just really nice sailingdog is just really nice sailingdog is just really nice sailingdog is just really nice
Andy-

A vehicle sitting on four tires is grounded, but nowhere near as well as a tractor or combine with metal bits dug into the ground. Whether a car is grounded or not has little effect on its ability to protect its passengers, since most cars have enough metal surrounding the passenger compartment to act as a rough faraday cage, preventing the lightning from injuring the passengers.

IMHO, the main reason to install a lightning grounding/bonding system on a boat is to protect the occupants. The main thing a lightning grounding/bonding system will do is help prevent sideflashes inside the boat. Sideflashes are probably the most lethal aspect of a lightning hitting a small fiberglass or wooden sailboat. One of my friend's boats got hit about ten years ago, and she said that the lightning leapt from the mast to the starboard chainplate and apparently exited the boat via the starboard chainplate. If she had been sitting on the starboard settee, it probably would have killed her. Her current boat has a 4' x 2" copper plate bolted/bonded to the hull, which is used as the termination for all the lightning grounding/bonding connections. It has five threaded copper studs that come through the hull that the connections are made to.

I don't have a lightning protection system on my boat. I chose to do so, knowing that the chances of my boat are lower by not having one, but take the risk that if I do get struck, far more damage will occur.
__________________
Sailingdog

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Telstar 28
New England

You know what the first rule of sailing is? ...Love. You can learn all the math in the 'verse, but you take
a boat to the sea you don't love, she'll shake you off just as sure as the turning of the worlds. Love keeps
her going when she oughta fall down, tells you she's hurting 'fore she keens. Makes her a home.

—Cpt. Mal Reynolds, Serenity (edited)

If you're new to the Sailnet Forums... please read this
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
.

Still—DON'T READ THAT POST AGAIN.
Reply With Quote Quick reply to this message Share with Facebook
  #28  
Old 08-22-2008
Senior Member
 
Join Date: Jun 2007
Posts: 535
Thanks: 0
Thanked 3 Times in 3 Posts
Rep Power: 8
GBurton is on a distinguished road
Do the studs simply extend through the hull into the water?

Quote:
Originally Posted by sailingdog View Post
Andy-

A vehicle sitting on four tires is grounded, but nowhere near as well as a tractor or combine with metal bits dug into the ground. Whether a car is grounded or not has little effect on its ability to protect its passengers, since most cars have enough metal surrounding the passenger compartment to act as a rough faraday cage, preventing the lightning from injuring the passengers.

IMHO, the main reason to install a lightning grounding/bonding system on a boat is to protect the occupants. The main thing a lightning grounding/bonding system will do is help prevent sideflashes inside the boat. Sideflashes are probably the most lethal aspect of a lightning hitting a small fiberglass or wooden sailboat. One of my friend's boats got hit about ten years ago, and she said that the lightning leapt from the mast to the starboard chainplate and apparently exited the boat via the starboard chainplate. If she had been sitting on the starboard settee, it probably would have killed her. Her current boat has a 4' x 2" copper plate bolted/bonded to the hull, which is used as the termination for all the lightning grounding/bonding connections. It has five threaded copper studs that come through the hull that the connections are made to.
I don't have a lightning protection system on my boat. I chose to do so, knowing that the chances of my boat are lower by not having one, but take the risk that if I do get struck, far more damage will occur.
Reply With Quote Quick reply to this message Share with Facebook
  #29  
Old 08-22-2008
sailingdog's Avatar
Telstar 28
 
Join Date: Mar 2006
Location: New England
Posts: 43,290
Thanks: 0
Thanked 11 Times in 11 Posts
Rep Power: 13
sailingdog is just really nice sailingdog is just really nice sailingdog is just really nice sailingdog is just really nice sailingdog is just really nice
The studs are part of the copper plate. They were soldered or brazed into the copper plate IIRC. The studs and the plate were tinned as well...
__________________
Sailingdog

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Telstar 28
New England

You know what the first rule of sailing is? ...Love. You can learn all the math in the 'verse, but you take
a boat to the sea you don't love, she'll shake you off just as sure as the turning of the worlds. Love keeps
her going when she oughta fall down, tells you she's hurting 'fore she keens. Makes her a home.

—Cpt. Mal Reynolds, Serenity (edited)

If you're new to the Sailnet Forums... please read this
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
.

Still—DON'T READ THAT POST AGAIN.
Reply With Quote Quick reply to this message Share with Facebook
  #30  
Old 08-22-2008
Senior Member
 
Join Date: Jun 2007
Posts: 535
Thanks: 0
Thanked 3 Times in 3 Posts
Rep Power: 8
GBurton is on a distinguished road
Did she design this system herself.......? Interested because my boat had a copper strip bonding the chainplates together then a #4 copper wire going down to a Dynaplate. I took it off

Quote:
Originally Posted by sailingdog View Post
The studs are part of the copper plate. They were soldered or brazed into the copper plate IIRC. The studs and the plate were tinned as well...
Reply With Quote Quick reply to this message Share with Facebook
Reply

Quick Reply
Message:
Options

By choosing to post the reply above you agree to the rules you agreed to when joining Sailnet.
Click Here to view those rules.

Register Now

In order to be able to post messages on the SailNet Community forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
Please note: After entering 3 characters a list of Usernames already in use will appear and the list will disappear once a valid Username is entered.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

 
Posting Rules
You may post new threads
You may post replies
You may post attachments
You may edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Lightning Strike! Kathy Barron Seamanship Articles 0 04-07-2005 09:00 PM
Lightning Strike! Kathy Barron Gear and Maintenance Articles 0 04-07-2005 09:00 PM
Lightning Strike! Kathy Barron Cruising Articles 0 04-07-2005 09:00 PM
Lightning Examined Kevin Hughes Seamanship Articles 0 05-10-2004 09:00 PM
Lightning Protection 101 Sue & Larry Seamanship Articles 0 11-22-1999 08:00 PM


All times are GMT -4. The time now is 10:29 PM.

Add to My Yahoo!         
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
SEO by vBSEO 3.6.1
(c) Marine.com LLC 2000-2012

The SailNet.com store is owned and operated by a company independent of the SailNet.com forum. You are now leaving the SailNet forum. Click OK to continue or Cancel to return to the SailNet forum.