Lightning protection for you boat

[Mike Banks]

And--for those who have metals dissimilar to copper or aluminium masts and are worried about the corrosion that copper fastened to it without an insulting plastic sheath will cause--if you go about twenty percent larger in diameter you can run aluminium rod or tube or flat strap--whatever--just so it has the cross-sectional area necessary to carry a current of about a few hundred amps initially.

No lightning rod of any kind is going to prevent damage from a fully developed discharge of millions of volts and thousands of amps..

The purpose of a lightning protection system is to stop that massive charge building up by discharging enough of it to stop the voltage or potential difference between the ground and the charged atmosphere becoming sufficient to form an ionised path to your vessel.

It is not as simple as saying "Imagine the charged atmosphere as one plate of a capacitor and the earth the other--with a high voltage across it--and all you need is a point which concentrates the charge and weakens the dielectric--and then one gets a discharge to that point"

The atmosphere is not of a constant conductivity. Some parts of it are far more conductive than others, because the atmosphere is a GAS mixture--and those gases when ionised cause a conduction path like the gas in a neon tube. It takes a high voltage to ionise it--but the jet stream provides millions of volts--and all it needs is some sort of atmospheric turbulence such as a thunder storm to facilitate ionisation.

Put up a lightning rod. It will conduct away the small strikes and dissipate any local ionised pathways.

Interestingly enopugh--in a lightning strike the current may flow first in one direction then another--and may change direction during a sustained discharge. Initially though--it almost always begins in the ground and travels from your vessel to the atmospheric charges--at least initially.

It is a fascinating subject--and the jury is still out on many aspects of it.

[MooseMarine]

Hi All,

The mast is "having a birthday" and the question of lightening protection has been raised. The Moose have been reading all the threads and are intrigued by the DDCE offering mentioned here.

It does come with some certifications and a installation list. They've been looking at the Spanish and Singapore sites.

FAQ - Dinnteco Spain

Moose, though not known for natural sailing abilities are open minded and potentially early adopters. Does anyone out there have any comment on the certifications and what they mean? The Panama Canal as a client is quite impressive.

Thanks and remember please don't shoot down the Moose!

MooseMarine

[danielamartindm]

My boat had lightning protection built in at the factory. It took a lightning strike a few years ago. Damage was limited to a frying of nav and com electronics. Given the sheer power of lightning, it's hard for me to conceive of ANY system completely obviating damage from a strike.

[Paul L]

Originally Posted by MooseMarine

Hi All,

The mast is "having a birthday" and the question of lightening protection has been raised. The Moose have been reading all the threads and are intrigued by the DDCE offering mentioned here.

It does come with some certifications and a installation list. They've been looking at the Spanish and Singapore sites.

FAQ - Dinnteco Spain

Moose, though not known for natural sailing abilities are open minded and potentially early adopters. Does anyone out there have any comment on the certifications and what they mean? The Panama Canal as a client is quite impressive.

Thanks and remember please don't shoot down the Moose!

MooseMarine

Their effectiveness analysis is pretty meaningless.
http://en.dinntecospain.com/efectividad/
They could at least have had a comparison site to show any difference. Even then, it would have been a far too small sample.

[GARRYOWEN]

delete

[Kenton]

ROY SULLIVAN

Wood masts.

[Kenton]

Originally Posted by SailFastTri

Do you have the experience or research to back this statement? It sounds like it might be opinion or generalization, based on ???.

It's pretty well established in the research papers of lightning "experts" that AWG#8 is sufficient to conduct a single strike and AWG#4 is sufficient to withstand multiple strikes. Either one is a lot thinner than a leg.

"do modern multihull manufacturers build in any lightening protection?" Generally not, but it can be added. Much easier to do during manufacture, before the hull interiors are finished.

Granted, this is for residential construction (NEC), but grounding electrode conductor gauge varies according to the gauge of the largest neutral conductor feeding the service panel. If you can relate that to boats, the mast is a pretty big conductor.

[Kenton]

Originally Posted by Alberg30Shill

My chartplotter, VHF and Tiller pilot all live in an aluminum case with foam inserts so act as a Faraday cage. I remove them when travelling and on a long passage could be put back in during a lightning storm while holding a compass course manually. All of my mast connectors are left unconnected when docked or anchored too except anchor light if needed. Not a total solution but reduces risk of equipment failure right?

EMP bags are available and would be easy to stow. Has anyone used them to protect onboard electronics?

[GordMay]

Originally Posted by Kenton

Granted, this is for residential construction (NEC), but grounding electrode conductor gauge varies according to the gauge of the largest neutral conductor feeding the service panel. If you can relate that to boats, the mast is a pretty big conductor.

Greetings and welcome aboard the CF, Kenton.

Actually:
There are two (2) classes of material requirements found in NFPA 780, the Standard for the (Shoreside) Installation of Lightning Protection Systems. Class I materials are required for structure less than 75-ft in height, and Class II Materials are required for buildings greater than 75-ft in height. The (lightning ground) down conductor is properly listed in the standard as a “Main Conductor Cable”.
Class I – Copper: Minimum Gage is 2 AWG, with a minimum individual strand size of 17 AWG.
Class II – Copper: Minimum Gage is 00 AWG, with a minimum individual strand size of 17 AWG.

[Jerry Woodward]

In his book, "Boatowners Mehanical and Electrical Manual" Nigel Calder devotes a significant section to Lightning protection. It is mainly focused on providing a path to ground from the mast to a plate in the water directly below the mast. He also advocates bonding the chainplates from the standing rigging to this ground. He also discusses methods for protecting electrical circuits. He seems to be well aware of the limitations of these systems, but concludes that they help mitigate damage.

[Kenton]

Originally Posted by Jerry Woodward

In his book, "Boatowners Mehanical and Electrical Manual" Nigel Calder devotes a significant section to Lightning protection. It is mainly focused on providing a path to ground from the mast to a plate in the water directly below the mast. He also advocates bonding the chainplates from the standing rigging to this ground. He also discusses methods for protecting electrical circuits. He seems to be well aware of the limitations of these systems, but concludes that they help mitigate damage.

Funny you should mention that book. I started it three days ago and am halfway through the second chapter. Killer book, but reading it takes some concentration. IPad says I only have 55 hours of reading left!
If good books on the other home systems take me as long to finish as this one, lightning won’t matter anymore. By the time I understand all the systems I’ll be too old to sail!

[dalav8r]

Has anyone tried installing a Flux Capacitor? 😜

[GordMay]

Greetings and welcome aboard the CF, dalavSr.

[rourkeh]

There is nothing you can do...

[pacesetter]

A question in the general radio operators test for the FCC asks what type of lightning protection works best for direct hits to a mast. The correct answer is nothing can protect against a direct hit. I disconnect the mast antennas while active lightning is present with Lin 25 miles of the boat.