Catamaran Lightning protection

[Falbala60]

Is there catamaran manufacturer that offer "Lightning protection" option ... never saw or heard that with Lagoon or Leopard ? Is is standard ?

Lot of "electronic burning" ... but no comment on damage to the hull or passage on the lightning.

I am a 50 years experienced monohull cruiser and racer had C&C's 25, 29 and then 35 until 10 years ago and now for my retreat I want to buy a cruising catamaran in the Caribbean.

So l am looking for the way catamarans are protected because the bottom mast tip is very far from "a non existent keel" and I worry about how the potential will travel through mast, cabin, rigging, etc. with the least damage ...

My 5cents experience ....
I am a mechanical engineer having some electrical knowledge and in the years 1980, with my first C&C 25 I had to deal with lightning protection. All "older sailors" said to me, GROUND your mast and if you can add a 2ft copper rod with a pointed tip on the top of your masthead ... do it !

They said "in that way the potential between your boat and the clouds will be minimum and if the potential raise too much you will hear sizzle" when little sparks will discharge through your grounded mast. For all my boats I did not install the copper rod, but I have connected 3 copper cables #6 from my mast end to the bolts of my lead keel.

One day in 1985 with my C&C29, on Lake Champlain I was going north along Ile Lamothe when came from west a so dark and low cloud. I navigate close to the shore with large trees, maybe 300ft, said to my wife and children to stay outside with me and close to the entrance of the cabin, away from the back stays and the mast. I moved myself close to them driving with a hand in the back.

Then that huge low black cloud, came slowly over us, maybe 200-300 feet over the mast, it was pure silence as we where under sail, no word, an slowly it passed over us until a HUGE LIGHTNING... a HUGE BANG hit the trees just beside us ... nothing ABSOLUTELY NOTHING to us. My masthead was higher than the trees.

So from this time,, I know I am well protected. and I my sailing career I passed through 20 other similar storms ... and nothing !

A friend of me had a 25ft sailboat when I made my "grounding protection" and he said I was overstressing about that. One day just in front of the Quebec Yatch Club, he was hit, water started to come into the boat and my chance he rushed in the marina and he landed his boat on the "trailer slope" (English term?) . When they succeeded to put the boat on his trailer, they found the hull completely delaminated under the mast... a chance this did not happens in the middle of the Golf in a 38F salt water ...

Like to know others minds or experience
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300

[Row Bear]

Manta have a factory installed grounding system for lightning.

[Seaslug Caravan]

Originally Posted by Falbala60

..

Like to know others minds or experience
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Its 2017 for goodness sake.

Around the time that most agreed the world wasn't flat, agreement was reached amongst physicists who did not have a vested interest in companies that sold lightning protection systems that lightning protection systems are a scam.

Has it never crossed your mind that if they really "worked" on yachts, then all reputable insurance companies would demand them to be fitted?

[GordMay]

Greetings and welcome aboard the CF, Falbala & Row Bear.

Ideally, I would bond my Catamaran (were I lucky enough to own one):
- chainplates and all significant metals to an external grounding strip (or Dr. Thomson’s “Siedarc” electrodes*) on each hull (minimum #6AWG Cu. Cable);
- and my mast base (air terminal at top) to a “portable” ground plate via a “Strikeshield” (or other) mast terminal (also #6 AWG minimum).

* See Marine Lightning Protection Inc. ➥ Marine Lightning Protection Inc.

BTW: Lightning protection works to mitigate damage when struck, not to prevent a strike.

[thomm225]

The bad news is with or without " lightning protection? ", catamarans get hit more than monohulls

[jdazey]

Originally Posted by thomm225

The bad news is with or without " lightning protection? ", catamarans get hit more than monohulls

Evidence?

[Captsteve53]

Catamarans have their own special set of issues:

According to Boat US insurance claims, they are struck twice as frequently as mono-hulls of similar length.

Their two hulls mean that there is twice as much waterline to contend with.

The bridge deck being suspended above the water introduces yet another vulnerability for side flashes.

Dont see why the normal mono hull situation wont work for a Cat (Ground Mast/Rigging with heavy copper wire (or better flat strap/or braid) and run to an external ground plate mounted on each hull, I have seen a few very nice jobs actually flush mounted on each hull with thru hull bolt and connected to the mast/rigging- (lot of work how ever!)


Here's a good link to Cat specific lightning issues and idea's

Catamarans


Cheers Steve

[Captsteve53]

Actual evidence!!! Note the mast blown off the boat into water!!

[Flip-Flops]

On our Lagoon 380 the chain plates are grounded to both the engine block and hull anode.

I don't believe the purpose of the cable is to dissipate a strike more so to dissipate static build up to prevent a strike.

[GordMay]

Originally Posted by Flip-Flops

On our Lagoon 380 the chain plates are grounded to both the engine block and hull anode.

I don't believe the purpose of the cable is to dissipate a strike more so to dissipate static build up to prevent a strike.

Greetings and welcome aboard the CF, Flip-Flops.
I believe that the expert consensus is that the purpose of the bonding/grounding IS to dissipate the strike (provide a preferred path to gnd), and not to prevent a static build-up.

A few of many earlier lightning discussions:

➥ http://www.cruisersforum.com/forums/...ion-72805.html

➥ http://www.cruisersforum.com/forums/...ood-99714.html

➥ http://www.cruisersforum.com/forums/...em-3138-2.html

[thomm225]

Originally Posted by jdazey

Evidence?

From the link below:

as far as lightning is concerned, two hulls are better than one. Multihull sailboats are almost twice as likely to have a lightning claim as monohulls. But that's only true if that big, pointy thing is in the middle of the boat. The frequency of pontoon boat lightning claims is well below the average.

Striking Lightning Facts - Seaworthy Magazine - BoatUS

[Captsteve53]

Further to my above post, i forgot I saw this "newish" idea as:

New SiedarcTM features single component silicon bronze electrode
The 3/8-16 stud on the connecting end of the solid silicon bronze electrode provides flexibility for many different types of connections, as shown in the photos below. The absence of any plating on these electrodes means that tips can be sanded without causing galvanic problems if fairing into the hull surface is desired.

I'm thinking if the the ELECTRODE (which you cant see) is large enough it could present a good path for the lightening to exit with out harm to the surrounding fitting(which i would prefer to see in Acetyl Nylon rather than whats shown, but an idea worth expanding on.

[Falbala60]

Capsteeve53
My convern about catamarans is the way to drive as vertical as possible the copper(s) wire whatever they comme from the mast base, chain plates, motor to the water.
With the "electodes through-hull" I woud'ld add a quite large bronze or copper plate... even many for mast, chainplates, motor, etc

[Captsteve53]

Understood re the plates and not disputing the issues at all , the whole idea of the fitting as shown is that inside the plastic thru hull (the bit you cant see)is the bronze electrode which is around 1 1/2" to 2" diameter or bigger depending on the thru hull chosen. this electrode is not the same size as the stud (only 3/8"), now in reality obviously a 1 ft square foot ground plate would be better (but harder to install ), i believe say four of these located in strategic locations and faired into the hull with say counter sunk thru hull fittings is going to be better for a Cat than having nothing at all.

There is a very good article on using these very grounding thru hulls here were they show how a 60 ft Cat was "grounded" using these above "thru hulls"AS:

Catamarans

Cheers Steve (MIIMS)-Lloyd's Maritime)

[Falbala60]

Thank you Capt Steeve
The electrode you propose to provide a direct path from the mast is exactly in the spirit of the solution I was "thinking". But any removable device for sailing time is prone to be forgoten when you leave the boat alone.