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Go Back   SailNet Community > On Board > Gear & Maintenance > lightning advice
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Topic Review (Newest First)
01-21-2013 03:47 PM
lancelot9898
Re: lightning advice

One note of clarification is that keel bolt in not really a keel bolt in the true sense of the word, but only a bolt that I assume makes contact with the iron encapsulated in the keel.
01-21-2013 11:31 AM
lancelot9898
Re: lightning advice

Hi Maine,

You mentioned that for an encapsulated keel with a keel step mast that you would mount a long copper bar stock with a lot of edge surface. Not sure just how you run that wire from the keel step to that bar stock. Also everything on my boat is bonded from the keel step to the thru hulls to the keel bolt of the encapsulted keel and etc. Never did feel right about that wire going to the iron ballast in the encapsulated keel in that there would seem to be a possiblity that the energy could go directly from the encapsulated iron to the water through the fiberglass possibly sinking the boat.
01-21-2013 09:33 AM
chef2sail
Re: lightning advice

Quote:
Originally Posted by Maine Sail View Post
Chef,

I removed that post 30 seconds after having made it as I saw the rest of the context..

I can assure you I would NEVER own a boat without primary/secondary lightning bonds. Our mast is done with 2/0 wire direct from mast step to a DRY keel bolt, made with terminal grease to prevent corrosion/high resistance.

The rest of the stuff is snake oil IMHO... I just finished two boats hit last summer. Both were newer boats with primary / secondary lightning bonding to ABYC standards. Neither had ANY hull damage, everything else was toast..

Our boats also had ZERO hull damage when hit but 25k in electrics...

You CAN NOT prevent a strike only try to guide it to ground as best you can. My only goal with lightning is to minimize hull damage as best I can....

A primary lightning bond is about $8.00 of wire for a keel stepped mast, maybe $30.00 for a deck step...

For an encapsulated keel this would be how I would do it...

Copper bar stock...Minimal drag, low cost, lots of edge surface...
Good,,,we agree

I am grounded from the mast show the same way to a keel boat with a large diameter ( either # or #1 wire) and I actually have a Newmar Ground shoe and its about 16-18". I noticed your plate was feet long. Is that suggested?

Dave
01-21-2013 07:49 AM
Maine Sail
Re: lightning advice

Quote:
Originally Posted by chef2sail View Post
Maine,

I am not saying not to have an effective way of grounding at all. I have it and had it and was still struck by lightning. I can still see the big flash inside my boat this summer when the bolt hit. This dispite a dynaplate grounding system and a burr dissapator on the mast head. I am no more afraid of a lightning strike now then I was before last summer, although I dont want to go through the experience again. They only way to prevent that is to stop sailing ( fat chance)

I respectfully disagree that you can prevent your boat from being struck or even direct the lightning without physical proof.

Do you have knowledge that having extensive lightening protection system on the boat other than basic grounding to the engine or a dynaplate is effective and will cause the lightening to follow that path andc minimize damage?

Most I have talked to including the most respected electric. electronics person here in Annapolis says you can waste thousands of dollars integrating this, but it is no gaurentee and there is not real data which indicates that the electricity from a strike, or side strike can be effecively DIRECTED to a SPECIFIC path.

He beleives in providing one or two ways of grounding as this may be one of paths the elctricity will follow and it would foolish not to at least provide a path and have things grounded.

He also beleives there is no proof that you can protect your boat from being struck other than to minimize where it is physically, nothing you can include on the boat which will act as a force field to shun the strike or to attract or not attract it.

If you have this knowledge share it so I and others can install it on or boats.

Surely if this works maybe we can convince the insurance companies to lower our policies, if we install these measures as we are less likely to have damage and if we do it will be less expensive to them.
Chef,

I removed that post 30 seconds after having made it as I saw the rest of the context..

I can assure you I would NEVER own a boat without primary/secondary lightning bonds. Our mast is done with 2/0 wire direct from mast step to a DRY keel bolt, made with terminal grease to prevent corrosion/high resistance.

The rest of the stuff is snake oil IMHO... I just finished two boats hit last summer. Both were newer boats with primary / secondary lightning bonding to ABYC standards. Neither had ANY hull damage, everything else was toast..

Our boats also had ZERO hull damage when hit but 25k in electrics...

You CAN NOT prevent a strike only try to guide it to ground as best you can. My only goal with lightning is to minimize hull damage as best I can....

A primary lightning bond is about $8.00 of wire for a keel stepped mast, maybe $30.00 for a deck step...

For an encapsulated keel this would be how I would do it...

Copper bar stock...Minimal drag, low cost, lots of edge surface...
01-20-2013 11:49 PM
chef2sail
Re: lightning advice

Quote:
Originally Posted by noelex77 View Post
isn't that what I said.

Chef2sail you seem convinced everyone is trying to sell something. Nothing to sell by me. A lightning grounding system uses standard components like heavy gauge wire.
No not you nolex, but Frogwatch was. He has since removed it from his posts but he was trying to sell and bonding/ grounding system.

He has either removed it now voluntarily or was asked to remove it. Here is part of what his post said

Quote:
Originally Posted by Frogwatch
Having routinely worked with multi-million volt potentials, I disagree with some advice given here. One can minimize the probability of the strike going thru certain paths by offering a much better path and eliminating paths that you do not desire.
Most effective would be a very good lightning ground.

Shameless commercial plug:

My new company is now selling a lightning groundv
Thats what I was referring to
01-20-2013 11:32 PM
outbound
Re: lightning advice

Some good info here. issue remains absence of fact as it relates to sailboats. However significantly more info and additional avenues to research posited since my last post. thank you. Orginal question was comparing simple ground plate from Ward's to groundng strip ( and other measures) from Marine Lightning.Still very interested in discussion of orginal question if possible.Tenor of discussion here would seem to favor simple solid ground plate. As said keel bolts not an option. Been told layered plates should be avoided as likely to explode as water turns to steam as plate heats. Devices to dissipate charge likely to be inadequate in this application. More likely to have some marginal effect in solute ( water) than air ( mast head). However again no empiric evidence of benefit to sailboats. Will tell builder to put in wire runs from shrouds to foot of mast/bilge area but not connect them until I get further concrete data or I am convinced it does not exist. Land is not a conducting solute of similar magnitude as seawater. Buildngs may have the high impedances a glass hull has but not the low impedance masts/rigging etc inbedded in them and sticking out of them. Transmitter and electrical towers are metal structures in their entirety. Physics must be different for particulars of sailboats. tx. again.
01-20-2013 10:36 PM
noelex77
Re: lightning advice

Quote:
Originally Posted by chef2sail View Post
The best you can do is ground evrything to a plate, give it a path...something which doesnt cost a lot of money and pray the lightning travels that path and doesnt seek an alternative.
isn't that what I said.

Chef2sail you seem convinced everyone is trying to sell something. Nothing to sell by me. A lightning grounding system uses standard components like heavy gauge wire.
01-20-2013 08:27 PM
chef2sail
Re: lightning advice

Quote:
Originally Posted by Vasco View Post
Interesting discussion. Here is my experience. Anecdotal data a n of 1.

I was sailing my CS36 Merlin on Lake Ontario, about seven miles offshore headed back to Toronto. Keel stepped mast, mast shoe bonded to Hydrokeel wing keel (lead) with large guage wire connected to shoe and a keel bolt. Through hulls are not bonded. All bronze.

Saw really bad (worse I've seen) electrical storm approaching. When lightning struck the water ahead on my port bow, then starboard bow, started motor, put handheld vhf in my foul weather gear pocket, got position from GPS, wrote it on a piece of paper and tucked that in my pocket too. Wind died, torrential rain.

BANG! I remember a sizzling sound, that was all my masthead stuff hitting the water just behind me. Guess it was red hot. Autopilot failed. Put on wheel brake and took hands off wheel. Called Canadian Coast Guard on handheld, reported position and having been struck, said I was going down below to check for damage and would report back in ten minutes. They said they would call SAR in Trenton and if I did not report back they would be out.

Checked boat for water. None. All instruments out, lights out, vhf out, alternator shot (no engine instruments). Some led's on electrical panel out. Oddly enough the Garmin GPS (a small Garmin 64?, not grounded) was still working. Called CG, reported situation, said I was continuing to Toronto (about 70 miles more) and would report every half hour but turning off handheld to conserve battery. They informed me that SAR had told them that damage might not be readily apparent such as keel bolts failing. I said thanks. If I did not report every half hour SAR would be out. We went another hour through the electrical storm, making slight corrections to the course but with wheel brake on and hands off. Got back to Toronto. Thanked CG.

Hauled the boat a day or two later. There was "treeing" (electrical burn marks in a very unique pattern) at every through hull and on the rudder at the gudgeon. The charge had gone throughout the boat. From stem to stern. No structural damage. Mast was pulled. Headsail showed slight burning at the foil. The headsail was a North with a zippered sleeve over the foil. (Sometimes the foil sections fuse together).

Replaced all instruments, alternator. Corrected magnetic compass. About $20K.
Glad you are OK...Remember the smell at all...I do
01-20-2013 06:44 PM
Vasco
Re: lightning advice

Interesting discussion. Here is my experience. Anecdotal data a n of 1.

I was sailing my CS36 Merlin on Lake Ontario, about seven miles offshore headed back to Toronto. Keel stepped mast, mast shoe bonded to Hydrokeel wing keel (lead) with large guage wire connected to shoe and a keel bolt. Through hulls are not bonded. All bronze.

Saw really bad (worse I've seen) electrical storm approaching. When lightning struck the water ahead on my port bow, then starboard bow, started motor, put handheld vhf in my foul weather gear pocket, got position from GPS, wrote it on a piece of paper and tucked that in my pocket too. Wind died, torrential rain.

BANG! I remember a sizzling sound, that was all my masthead stuff hitting the water just behind me. Guess it was red hot. Autopilot failed. Put on wheel brake and took hands off wheel. Called Canadian Coast Guard on handheld, reported position and having been struck, said I was going down below to check for damage and would report back in ten minutes. They said they would call SAR in Trenton and if I did not report back they would be out.

Checked boat for water. None. All instruments out, lights out, vhf out, alternator shot (no engine instruments). Some led's on electrical panel out. Oddly enough the Garmin GPS (a small Garmin 64?, not grounded) was still working. Called CG, reported situation, said I was continuing to Toronto (about 70 miles more) and would report every half hour but turning off handheld to conserve battery. They informed me that SAR had told them that damage might not be readily apparent such as keel bolts failing. I said thanks. If I did not report every half hour SAR would be out. We went another hour through the electrical storm, making slight corrections to the course but with wheel brake on and hands off. Got back to Toronto. Thanked CG.

Hauled the boat a day or two later. There was "treeing" (electrical burn marks in a very unique pattern) at every through hull and on the rudder at the gudgeon. The charge had gone throughout the boat. From stem to stern. No structural damage. Mast was pulled. Headsail showed slight burning at the foil. The headsail was a North with a zippered sleeve over the foil. (Sometimes the foil sections fuse together).

Replaced all instruments, alternator. Corrected magnetic compass. About $20K.
01-20-2013 06:35 PM
kd3pc
Re: lightning advice

Quote:
Originally Posted by chef2sail View Post
Ok I have read some of Blocks stuff and all seem related to antannnaes and ground communication stations etc, Maybe you could steer me to the specificdata and information on sailing vessels or boats in the water as I dfo nolt seem to be able to find this.

What kind of Robert Block methods have you emplyed on Tango to minimize lightening strike effects other than a simple grounding to a plate or the engine?

Would like to learn some other best practices as I have that on my boat already and that had NO effect.

Dave

Dave
for me, Block has good information on grounds, grounding and grounded items, as well as details about connections, especially mechanical ones, attachments and what measurements to expect to survive a hit, direct or otherwise. The concepts of very shallow bends in grounding conductors, size and materials of conductors and the theory that EVERYTHING must be at the same ground potential, ie 2.5 ohms or less to every item grounded appeals to me, he advocates against "old school" theories like concentric rings of grounds as they create loops and multiple paths.
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