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Old 16-08-2017, 12:17   #1
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Is our mast grounded?

Hello!
I have been searching everywhere to see if our Newport 28, 1981 sailboat has a grounded mast. We were recently given this boat and we are just learning to sail it and repair its many flaws. But in the meantime we are traveling down the ICW and there are thunderstorms everywhere and we can't seem to get any info on whether or not we need to worry about getting struck by lightening. I have looked an manuals, online specs, and sailing forums, and we have definitely searched on the boat for grounding wires (although we aren't totally sure if we would know it if we saw one). Any advice or information?
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Old 16-08-2017, 16:36   #2
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Is our mast grounded?

Real easy to test to see if it's grounded with a multimeter and a long piece of wire. Just look for continuity between the mast and a ground point on the boat.

However I know of no data that supports if its better from a lightning standpoint to be grounded or not, but admit I have a lot to learn, especially about lightning. The more I try to read about and study it, it's almost like it's sentient and just does what it wants to often not following any "rules"
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Old 16-08-2017, 16:54   #3
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Re: Is our mast grounded?

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Originally Posted by a64pilot View Post
Real easy to test to see if it's grounded with a multimeter and a long piece of wire. Just look for continuity between the mast and a ground point on the boat.
All that means is that it's grounded to the boat but not necessarily to the earth/sea.

But as you said, there is a big debate as to whether it's good to have lightning protection as in the boat being "grounded" to the sea

Some stats show that boats with lightning protection (grounded to the water/sea) get struck more often than those without but if they get struck have less damage


I decided to research the lightning thing after this day when just before the squall hit I was arguing with fellow CF members about the holding power of a CQR when I happened to hear the wind increase..........


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Old 16-08-2017, 16:55   #4
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Re: Is our mast grounded?

A64PILOT
That is not a good test for a lightning bond. It will just tell you if you have an electrical ground. A lightning bond takes a 6awg wire to an external grounding plate (1sq ft) such as an external keep to start to be successful.
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Old 16-08-2017, 17:01   #5
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Re: Is our mast grounded?

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Originally Posted by thomm225 View Post
But as you said, there is a big debate as to whether it's good to have lightning protection as in the boat being "grounded" to the sea

Some stats show that boats with lightning protection (grounded to the water/sea) get struck more often than those without but if they get struck have less damage
That's a hell-of-a choice
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Old 16-08-2017, 17:10   #6
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Re: Is our mast grounded?

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That's a hell-of-a choice
Yep, some guy called me on it on an earlier thread saying my data was inaccurate but I supplied him with three sources to back me up.

He never responded back.

Some points were that smaller boats get hit less due to shorter masts.

Catamarans get hit more often than monohulls etc


But on the day I spoke of before it was all good until the lightning. Here it is just before the thunder, lightning, and rain. just a bit of wind at a protected anchorage


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Old 16-08-2017, 17:38   #7
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Re: Is our mast grounded?

Quote:
Originally Posted by desoria View Post
Hello!
I have been searching everywhere to see if our Newport 28, 1981 sailboat has a grounded mast. We were recently given this boat and we are just learning to sail it and repair its many flaws. But in the meantime we are traveling down the ICW and there are thunderstorms everywhere and we can't seem to get any info on whether or not we need to worry about getting struck by lightening. I have looked an manuals, online specs, and sailing forums, and we have definitely searched on the boat for grounding wires (although we aren't totally sure if we would know it if we saw one). Any advice or information?
As Paul L posted, any lightening grounding wire will be at least 6 AWG. However it is usually bigger - much bigger. It will be attached to the mast via a lug / bolt somewhere near the base of the mast and be routed in a direct (or nearly direct) line to the hull below the waterline. Any bends should be large radius.

If you can't see something like this, then your mast is not grounded for lightening purposes.
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Old 16-08-2017, 17:57   #8
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Re: Is our mast grounded?

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Originally Posted by thomm225 View Post
Yep, some guy called me on it on an earlier thread saying my data was inaccurate but I supplied him with three sources to back me up.

He never responded back.


Some points were that smaller boats get hit less due to shorter masts.

Catamarans get hit more often than monohulls etc


But on the day I spoke of before it was all good until the lightning. Here it is just before the thunder, lightning, and rain. just a bit of wind at a protected anchorage


None of the 3 sources you linked to had any data supporting your claim that lightning grounded vessels get hit more often than non-grounded vessels.
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Old 16-08-2017, 19:30   #9
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Re: Is our mast grounded?

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Originally Posted by Wotname View Post
As Paul L posted, any lightening grounding wire will be at least 6 AWG. However it is usually bigger - much bigger. It will be attached to the mast via a lug / bolt somewhere near the base of the mast and be routed in a direct (or nearly direct) line to the hull below the waterline. Any bends should be large radius.

If you can't see something like this, then your mast is not grounded for lightening purposes.
What purpose is a grounding wire from the mast to the hull? It's already attached to the hull, and what grounding is fiberglass? Other than being in water, fiberglass is not the best conductor? I always wondered why a heavy wire, laying on rubber mats, from the mast to the water wouldn't be the best way to get proper protection?
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Old 16-08-2017, 19:34   #10
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Re: Is our mast grounded?

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Originally Posted by Flyingriki View Post
What purpose is a grounding wire from the mast to the hull? It's already attached to the hull, and what grounding is fiberglass? Other than being in water, fiberglass is not the best conductor? I always wondered why a heavy wire, laying on rubber mats, from the mast to the water wouldn't be the best way to get proper protection?
Needs to be connected to an exterior ground plate, such as the keel or copper strip, etc.
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Old 16-08-2017, 19:48   #11
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Re: Is our mast grounded?

I bought a piece of jet cable at Boeing Surplus. Super nice stuff, teflon insulation etc. big 0, 00?, It goes from a stainless 1/2 nut in the mast step to a lag bolt into the lead keel. Once I felt the heat from a strike it was so close, no problems so far.
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Old 16-08-2017, 20:30   #12
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Re: Is our mast grounded?

For input:

What follows is based on the recommendations for lightning protection provided by the American Boat & Yacht Council, Standard E4.

1)The primary purpose of a lightning protection system is to provide for the physical safety of all aboard your vessel. Prudent actions that should be taken during an electrical storm are:
2) If at all possible remain in the cabin of a closed boat.
3) No one should be in the water or have any part of their body immersed in the water.
4) Do not come into contact with any components connected to the lightning protection system of a properly protected vessel. Otherwise your body could act as a conductive bridge between any items connected to the lightning conductive system. For example, you should not be in simultaneous contact with a metal steering wheel and a metal stern pulpit.
5) A good lightning protective system ensures that all large masses of metal are electrically connected. This purpose should not be confused with that of the vessel's basic bonding system. A properly installed and isolated bonding system is there to provide a low resistance electrical path to reduce electrolytic corrosion and as a measure of personal protection if there is an electrical fault in the boat's AC/DC electrical systems.
6) If your sailboat is a vessel with an aluminum mast you have the starting point of a well-grounded lightning rod. This will provide a zone of protection for a radius around its base equal to the height of the lightning rod. Due to some vessels overall length, it may be necessary to install another lightning rod to encompass any areas that do not fall within the zone of protection.
7) Don't forget that the mast itself must be physically bonded or connected through to the common ground - one of the keel bolts or if a encapsulated keel, to the grounding plate, in order to provide optimum protection.
8) The apex of the rod should be a minimum of six inches above any masthead device. The end should be sharpened to a point. The base of the mast or the mast step if metal, should be connected to a keel bolt on externally ballasted vessels. The preferred wire gauge is No. 6 or even better, #4AWG stranded copper. In no case should such a connection be made to a vessel with internal ballast. The result could be a hole blown through the bottom of the hull. Boats with internal ballast should have a copper ground plate of at least one square foot in size installed externally on the hull bottom. The grounding wire should then be connected to the ground plate.
9) All wire conductors should be kept as straight as possible. All large metal objects above and below decks should also be electrically tied into the lightning ground conductor. This is a precaution against side flashes. Large metal objects include shrouds, chainplates, toe rails, sail tracks, winches, steering wheels, and bow and stern pulpits. These items can be tied into the ground conductor wire by a minimum #8AWG stranded copper gauge wire, or connected directly to the hull ground terminus.
10) A thorough inspection of the lightning protection system should be conducted on an annual basis as part of normal maintenance procedure. All connections should be maintained tight and corrosion free. Any corrosion will impede the flow of electricity and promote side flashes. For that reason it is important that the lightning protection system receive the same attention as the rest of the systems aboard the vessel. This should be included as a part of the annual lay-up and maintenance procedure. For additional details regarding the lightning protection standards readers should refer to American Boat and Yacht Standard E-4

Source: ABYC Recommendations on Lighting Protection in The Marine Advisor,

Cheers Steve
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Old 16-08-2017, 20:39   #13
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Re: Is our mast grounded?

Quote:
Originally Posted by Flyingriki View Post
What purpose is a grounding wire from the mast to the hull? It's already attached to the hull, and what grounding is fiberglass? Other than being in water, fiberglass is not the best conductor? I always wondered why a heavy wire, laying on rubber mats, from the mast to the water wouldn't be the best way to get proper protection?
I sort of thought it was obvious that there would need to be a metal grounding plate on the outside of the hull. I didn't realise some would not realise this.

My post was to help the OP find any grounding wire and there would no point in telling him to look underwater for any plate if there was no heavy cable from the base of the mast to the inside of the hull.

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Old 17-08-2017, 03:43   #14
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Re: Is our mast grounded?

Greetings and welcome aboard the CF, desoria.

The mast lightning ground might be a large wire/cable, connected to the bottom of the mast and a keel bolt.
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Old 17-08-2017, 03:54   #15
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Re: Is our mast grounded?

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None of the 3 sources you linked to had any data supporting your claim that lightning grounded vessels get hit more often than non-grounded vessels.
So you went back to that thread?

If you did it's there.
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