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Lightening protection for 42 ft Bertram Flush Deck

Discussion in 'Bertram Yacht' started by Bahma, Nov 27, 2015.

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  1. Bahma, Nov 27, 2015
    #1
    Bahma

    Bahma Member

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    having recently talked with a owner of a similar boat, who paid some $140K for replacement of all electrics and electronics, including main engine computer controllers, after being struck by lightning, how does one make a boat safe from lightening strike?

    Thank you
  2. Marmot, Nov 28, 2015
    #2
    Marmot

    Marmot Senior Member

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    Other than a floating Faraday cage that completely encloses the boat, there is no add on device that will protect the boat.

    The only defense against paying a great deal of cash out of pocket to repair lightning strike damage is a well worded insurance policy or moving to the north or south pole ... and luck of course.
  3. captholli, Nov 28, 2015
    #3
    captholli

    captholli Senior Member

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    You can limit damage by insuring that all major bonding wires & connections are not bundled with other electrical conductors and are separated in wire trays so electromagnetic "conductor jumping" doesn't occur. Give lightning the best possible path of low resistance to ground to by installing a large surface area Dyna plate or ground plate on the bottom of the hull. Some boaters swear by air terminals mounted at the apex or highest point of the vessel to create a aurora around the vessel. I'm not certain that this is proven science or not but the simple answer to your question is that you can only take steps to mitigate damage from lightning but at this point there's no such thing as lightning safe.
  4. Capt Ralph, Nov 28, 2015
    #4
    Capt Ralph

    Capt Ralph Senior Member

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    Not my design, but our fly bridge hard top and arch is all alloy.
    I see lightning and I cringe and worry.
    My only hope is the factory copper straps (two and large) that run down each beam to two Dyna-Plates.
    Our Bert was also factory rigged (1978) with copper sheeting in the electronics box, in the wheel house overhead and lining a small cubby in the port saloon where some old, multi part SSB equipment used to be.
    This cubby is my Fariday cage for handheld equipment.

    All of this may seem fancy, I still cringe and worry. Thru the years I have learned that lightning can not be understood, guided, controlled or protected from with any confidence. It is truly luck that we have had minimal lightning issues.
  5. Capt Ralph, Nov 28, 2015
    #5
    Capt Ralph

    Capt Ralph Senior Member

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    Typing of luck.
    Were at the Jib Room puttin down some BBQ. Our ship on the T fuel dock, a few years back.
    I just looked up and witnessed a lightning strike (not raining) at the Conch House/Curly Tails docks. In the middle of about 20 rental sail botes was one smaller (shorter) lil bote that took a direct hit. Within minutes it was fully involved a-fire. The fast action of all on the docks saved the rental fleet and others.
    So much for the taller sticks getting hit first, little mast surround by a taller forest of mast got hit.
  6. d_meister, Nov 28, 2015
    #6
    d_meister

    d_meister Senior Member

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    Marmot is right, there really is no physical protection. I once performed an electrical survey on an aluminum yacht in Ixtapa that had a neighbor boat suffer a direct hit. The Electro Magnetic Field generated destroyed every semiconductor on the boat that I surveyed. The hand held GPS and handheld VHF's that were in a drawer wouldn't power up, and a diode set in a metal control box with a transformer for electric hatch lifts were also blown. The microwave oven was dead. The magnetic contactor for the AC anchor windlass in a metal enclosure was dead. Those things were unexpected, but the electronics package was all damaged, too; radar , plotter, fixed GPS, VHF, SSB. Incidentally, the boat was one of two that the Captain maintained for an owner with very deep pockets, so insurance opportunism wasn't an issue. The Brit Captain was as surprised as anyone that these things were affected, assuring us that everything worked before.
  7. Bahma, Nov 28, 2015
    #7
    Bahma

    Bahma Member

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    Thanks for the info and comments,........ I've spent the past 50 odd years living in Nassau and cruising around the Bahamas, ........during the old days before water makers....... we would chase thunder storms so both boat and family could get a fresh water wash down.,....... for a family of 5 kids and two adults......a 200 gallon water tank didn't last too long.

    Never during all that time and many thunder storms, did we have any lightning strikes, although some were quite close.

    The V8 gas engines in my Chris Crafts and the 671s in my Huckins, were all pre computers, but now, my Bertie with her computerised Yanmars, fly by wire engine controls and Garmin chart plotter, is a different kettle of fish......lightning would leave me dead in the water, with no engines, no steerage and probably no comms.

    I know there is no magic, but I suddenly feel quite vunerable, my friend to whom I referred was hit in the Exumas, and had to be towed by three three separate companies to Florida and points further north in order to have the damage rectified. Cost for towing approx. $40K.

    Perish the thought..... hope the next 50 years are equally uneventful.

    Bahma.
  8. Marmot, Nov 29, 2015
    #8
    Marmot

    Marmot Senior Member

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  9. SplashFl, May 20, 2021
    #9
    SplashFl

    SplashFl Active Member

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    Forty years ago after hearing about these from a guy with a "stick" boat down the canal I bolted one to the top of the Tuna Tower on my Bertram here in S. Florida. His mast had previously been hit. Fifteen years later he sold his home and went sailing round the planet and settled in Ha. About a dozen years ago I started to notice them on FPL pole electric equipment all over Broward County & on all of the Counties Traffic CAMS. Do they work? I've heard all the arguments & all I can attest is I never had any lightning issues up to the sale of the boat a few weeks ago.
    airterminal.jpg
  10. NYCAP123, May 20, 2021
    #10
    NYCAP123

    NYCAP123 Senior Member

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    You'd think that by now someone would have filled a field with telephone poles and mounted various lighting rod systems and recorded the results.
  11. SplashFl, May 21, 2021
    #11
    SplashFl

    SplashFl Active Member

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    Now there's a use for the many old condemned ATT Poles they've been dragging their asses for years in removing but the environmentalists would howl so loud they'd be heard across the big pond if the "field" was in the Glades. The cost of dry land now well over 7 figures per acre down here but that would be a more worthwhile study then many we hear the government funds. Should be able to find out how the little fuzzy things have been doing in protecting the many road cam's in this county, although I have reason to believe many of them, for whatever the reasons, either don't work, no one pays attention to them, or they were fake to begin with.