Cruisers Forum
 


Reply
  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on Cruisers Forums. Advertise Here
 
Thread Tools Search this Thread Rate Thread Display Modes
Old 16-11-2020, 10:57   #76
Registered User
 
capn_billl's Avatar

Join Date: Aug 2010
Location: Naples, FL
Boat: Leopard Catamaran
Posts: 2,572
Re: Lightning Protection for Electronics

Oh, alternator diodes.

Good call.

A 12v diode connected between the boats electronics, and a positive 12v wire goes to every system on the boat including mast top light.

And is connected to a ground via engine prop shaft.

That little diode is the only thing between your anchor light, and your prop.
capn_billl is offline   Reply With Quote
Old 16-11-2020, 11:59   #77
smj
Registered User

Join Date: Nov 2007
Boat: TRT 1200
Posts: 7,265
Re: Lightning Protection for Electronics

Quote:
Originally Posted by Alistair242 View Post
Did it defuse it? Are they not supposed to divert the lightening away from the mast?


They are supposed to and it did not.
smj is offline   Reply With Quote
Old 16-11-2020, 12:02   #78
smj
Registered User

Join Date: Nov 2007
Boat: TRT 1200
Posts: 7,265
Re: Lightning Protection for Electronics

Quote:
Originally Posted by Frankly View Post
It diffused the $ balance in his checking account, and diverted funds away way from a more useful boat toy.





Frankly


I bought the boat after it had been struck. Only way I could afford a boat like that so it was actually a good thing for us!
smj is offline   Reply With Quote
Old 16-11-2020, 12:41   #79
Registered User

Join Date: Jan 2014
Location: Panama City FL
Boat: Island Packet 32 Keel/CB
Posts: 995
Re: Lightning Protection for Electronics

Think the issue is the definition of "Protection".

If your meaning of protection is never being struck, then don't think you will find any knowledgeable individuals that will say such a system exists.

My definition of protection is for the inhabitants and the basic vessel to come out the other side of a significant strike without major injury/damage. Electrical and electronics all bets are off.

The sailing yacht is actually a simpler problem than a lot of structures.
1. It is floating in a better conduction medium (sea water) than most soils.
2. It is usually comes factory equipped with this aluminum pole towering above all the other structure.
3. The missing link is the connection from mast to seawater (not trivial but not real difficult either).

As to actual strike event.

Years back, a shake you out the bed strike occurred right outside my bedroom. Turned out the main recipient of the discharge was an oak tree about 25 ft from my bed.

Located within 50 ft or less of that tree were two sailboats both with copper ground plates electrically connected to the mast. Got the radar on one and the inverter charger on the other. No other electrical damage. The Island Packet factory bonding system includes a ground wire from the port backstay to the engine/ bonding system. The lug on that wire was nearly burned completely through where it connected to a collecting terminal strip. I had redone all those connections within a couple of years previous and I check on most my electrical system quite regularly. I am convinced that the failure of that connection was related to the strike.

Was this a large inductive pickup with enough current to overheat the connection, did a side leg of the strike attach to the IP mast and enough current flow through to overheat this connection. No way to really know.

Many years back a local High School student was killed by a lightning strike and was standing within spitting distance of a typical Faraday lightning system on her single story school building.

With lightning, no guarantees just trying to shift the odds.


Frankly
Frankly is offline   Reply With Quote
Old 16-11-2020, 13:35   #80
Registered User

Join Date: Nov 2020
Posts: 92
Re: Lightning Protection for Electronics

Quote:
Originally Posted by justinfinity View Post
Give me a single example of any sailboat anywhere with evidence that it sustained a direct hit and was not damaged intact and I'll consider it. Don't tell me about aircraft or structures on land. I want to know about sailboats.
how about a power boat, direct hit with zero added lightning protection?

The story I posted about earlier about my dad's boat when I was a teen....
It's not a story of an undamaged hit...but I feel it does point to something....
direct hit to the radio antenna
two independent windshield wiper motors.... one switched on, the other switched off
various lights switched on, others switched off
etc....
ALL the things switched on melted...pile of goo. ALL the things switched off survived.

Anecdotal...but I've gotta beleive that if we'd switched off everything that a lot more of it would have survived.

No way some little DC circuit on/off switch has enough air gap to stop lightning...but there was something about the stray voltage spike on a closed circuit.... so that tells me there are ways to mitigate the damage
skyhawk is offline   Reply With Quote
Old 16-11-2020, 13:39   #81
Registered User
 
Dave_S's Avatar

Join Date: Jun 2016
Location: Brisbane Australia
Boat: Schionning Waterline 1480
Posts: 1,987
Re: Lightning Protection for Electronics

Quote:
Originally Posted by Steve DAntonio View Post
Aircraft and marine lightening mitigation techniques are significantly different, You are right, AC are routinely struck by lightening with no ill effects, they are a faraday cage. Yachts need a good ground path, and I don't believe any system can prevent a strike. Agreed on the snake oil, no shortage of that.

More here https://www.proboat.com/2016/04/3530/
I was in an aircraft that was hit by lightening. My mother and I both saw it go through the wing. What surprised me is it seemed to go straight through, I imagined it would not exit directly below where it entered. It made me question if it did actually hit us or not. A few minutes later the pilot confirmed we were hit and that all systems were fine, I expect there was quite a comprehensive check list.

I still wonder why it appeared to go straight through. If it is a Fariday Cage and the current passes around the outer skin why would it exit inline ?
__________________
Regards
Dave
Dave_S is offline   Reply With Quote
Old 16-11-2020, 13:46   #82
Registered User

Join Date: Nov 2020
Posts: 92
Re: Lightning Protection for Electronics

I surprised that it's not pretty much a given that all sailboat manufacturers would bond the metal mast to something in the water. Living in FL, it to me just seems like an obvious thing to do, no???
skyhawk is offline   Reply With Quote
Old 16-11-2020, 13:55   #83
Registered User
 
Dave_S's Avatar

Join Date: Jun 2016
Location: Brisbane Australia
Boat: Schionning Waterline 1480
Posts: 1,987
Re: Lightning Protection for Electronics

My boat has no metal work in the water unless I'm anchored or dropped the motors down.

Am I at greater or reduced risk of hull damage, I can live with the electrics but I don't like holes.
__________________
Regards
Dave
Dave_S is offline   Reply With Quote
Old 16-11-2020, 15:32   #84
Registered User

Join Date: Jan 2014
Location: Panama City FL
Boat: Island Packet 32 Keel/CB
Posts: 995
Re: Lightning Protection for Electronics

Quote:
Originally Posted by skyhawk View Post
I surprised that it's not pretty much a given that all sailboat manufacturers would bond the metal mast to something in the water. Living in FL, it to me just seems like an obvious thing to do, no???

One often explanation for why mfgs do or do not do things is " look at the local L/E ratio".

What is the L/E ratio you ask heard of the L/R (common inductance over resistance number in many electrical calculations). L/E ratio is number of lawyers divided by the number of engineers. If this number is over 10 then mfg behavior is affected.

If you provide a lightning protection system and something happens you might be visited by an out of work lawyer. Provide no system, something happens, "you should have installed a protection system". CYA is a real business consideration. Hate to be a cynic but just the way it is.


Frankly
Frankly is offline   Reply With Quote
Old 16-11-2020, 16:39   #85
Marine Service Provider
 
Steve DAntonio's Avatar

Join Date: Jun 2018
Location: Virginia
Posts: 105
Re: Lightning Protection for Electronics

Quote:
Originally Posted by justinfinity View Post
Give me a single example of any sailboat anywhere with evidence that it sustained a direct hit and was not damaged intact and I'll consider it. Don't tell me about aircraft or structures on land. I want to know about sailboats.
I've seen many, albeit anecdotally rather than scientifically. As I noted in the article to which I linked, I've seen well bonded sailing vessels, with some but not all components of the ABYC Lightning mitigation system, take direct hits, have the VHF whip melt and fall into the cockpit and damage the gelcoat, with no other damage, the VHF even still worked. By the same token, I've seen a trimaran with no bonding system struck, blow out a transducer and sink at the dock.

When I managed a boat yard on the Chesapeake Bay, where lightnings prodigious, I undertook scores of lightning repairs. There's no doubt, it is unpredictable, no one can predict with certainty what it will do, however, from that experience my conclusion is well-grounded/bonded vessels suffer less damage.
__________________
Steve D'Antonio
Steve D'Antonio Marine Consulting, Inc.
ABYC Certified Master Technician
Steve DAntonio is offline   Reply With Quote
Old 16-11-2020, 16:41   #86
Marine Service Provider
 
mitiempo's Avatar

Join Date: Sep 2008
Location: Victoria B.C.
Boat: Wauquiez Centurion 32
Posts: 2,874
Re: Lightning Protection for Electronics

Quote:
Originally Posted by Dave_S View Post
My boat has no metal work in the water unless I'm anchored or dropped the motors down.

Am I at greater or reduced risk of hull damage, I can live with the electrics but I don't like holes.
Greater. If hit it has to find a way out.

See this link. Boat not grounded and 2 holes blown in the bottom.



mitiempo is offline   Reply With Quote
Old 16-11-2020, 17:43   #87
Registered User

Join Date: Jun 2013
Location: Queensland
Boat: Lidgard yacht 32ft
Posts: 276
Re: Lightning Protection for Electronics

Was in a Marina in Queensland during a terrible storm. A bolt of lightning hit the water really close. One yacht went to leave the next morning. Zero starter motor, depth sounder & bow thruster. Conclusion was that the charge must have travelled through the water.
Davo1404 is offline   Reply With Quote
Old 16-11-2020, 19:34   #88
Registered User

Join Date: Jun 2019
Posts: 33
Re: Lightning Protection for Electronics

Not knowing much about electricity, I am nevertheless interested when it comes to lightning. I doubt that there are many who have not had some kind of scare during a lighting storm. I have. I do not own a boat, but have, and I've followed this forum for some time.


I offer this suggestion: Perhaps do something to prevent the boat, etc. from being "seen" by lightning. As I understand it, lightning occurs when something on the ground sends some sort of charge into the air that the lightning responds to, "sees."
I'm not sure, but there may have been examples where boats with shorter masts were hit in a marina, while taller masts were not. So, why did the lightning "see" these shorter masts & not the taller ones?


There must have been some kind of "welcoming" charge coming from these boats that attracted the lightning. In short, I suggest looking into how to keep boats from being "seen" by lightning, preventive measures, IOW, instead of coping with being struck. I'm not versed in electrical nomenclature and plead ignorance; this is only a suggestion from what little I understand.
Sonny36 is offline   Reply With Quote
Old 16-11-2020, 20:32   #89
Registered User

Join Date: Jan 2019
Posts: 164
Re: Lightning Protection for Electronics

Hi All, CaptVR here.
I was a marine surveyor for 25+ years, done lighting damage for all major underwriters. Been to a dozen seminars on lighting and lightning protection.
There were two schools of thought and this was gathered from 1000's of investigations over a decade done by the insurance industry. 1. Do not bond a thing, all totally open an un bonded. Have your hound, top of wood mast grounded to keel with a #6 solid copper bond wire. That is it, thought being top of mast will give cone of protection to all other metalic items. 2. Bond everything on the boat, if its metal, it's in a bonding system that covers the entire boat, supposedly protecting the entire boat. All the experts would only agree on one thing, do one or the other, don't bond half the boat and leave half unbonded.
Here is my findings after hundreds of lightning strike inspections. Some boats had no bonding, virtually no damage to everything blown or burned. Million dollar Swan with $20k of lightning protect (this was 20 years ago) had a strike, blew every breaker apart. Burned buss bars, melted a SS halyard into millions of SS BB's on the deck, even blew light fixtures apart. The owner did everything you could do for protection, even that carbon snowball on the masthead. This was the worst I had ever seen for damage from lightning.
My conclusion, I don't care what you do, pick a card. Its up to the God's. This is not guessing, this was personal observations. Do a lot, do a little, do full bonding, or no bonding, or bond a little. Nothing I seen would indicate better protection than anything else. How lucky do you feel!!!
With inspecting for 3 decades, I never seen a bronze thru hull blown off, never seen a hole burned through the bottom of a boat, wood, FRP or metal. Out of all that time, and hundreds of lighting strikes, I inspected one partial sinking due to a lighting strike. It appeared that the strike discharging at this thru-hull melted and blew the hose off of the fitting. It all boils down to, HOW LUCKY ARE YOU !!!
Sail Safe All, Capt. Vince Rakstis Ret. MS St.Petersburg, Fl.
CF32907 is offline   Reply With Quote
Old 16-11-2020, 20:59   #90
Registered User

Join Date: Feb 2018
Posts: 1,126
Re: Lightning Protection for Electronics

Quote:
Originally Posted by CF32907 View Post
Hi All, CaptVR here.
I was a marine surveyor for 25+ years, done lighting damage for all major underwriters. Been to a dozen seminars on lighting and lightning protection.
There were two schools of thought and this was gathered from 1000's of investigations over a decade done by the insurance industry.....
Thanks for your insight. I'm curious to your take on how/why insurance companies would give a discount to folks who install these lightning protection systems for boats when damage is intrinsically hit or miss?

I wonder if the "bottom end" of the insurance market is feeling the squeeze for paying for high-end boat damage, including lightning which is sort of common. In the aviation world Boeing insurance woes are trickling down such that even little Cessna owners have experienced pretty big increases in premiums. It's as though insurance is becoming more lazy/comfortable with slow dimes than fast nickles?
Singularity is offline   Reply With Quote
Reply

Tags
electronics, lightning, rot

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Lightning protection for a catamaran Crak Multihull Sailboats 51 23-07-2021 01:17
Built-in Lightning Protection for Electronics stillbuilding Marine Electronics 8 23-02-2010 00:42
Lightning Protection JusDreaming Health, Safety & Related Gear 57 03-10-2007 10:25
NFPA 780 Lightning Protection Systems GordMay The Library 0 16-01-2006 03:53
Lightning Protection Stede Electrical: Batteries, Generators & Solar 5 20-11-2003 17:27

Advertise Here


All times are GMT -7. The time now is 00:14.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2024, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.