Click for Mag Bay Click for MotorCheck Click for Abeking Click for Furuno Click for Ocean Alexander

Lightning strikes onboard a yacht

Discussion in 'Technical Discussion' started by sagharborskip, Sep 20, 2008.

You need to be registered and signed in to view this content.
  1. sagharborskip

    sagharborskip Senior Member

    Joined:
    Sep 7, 2008
    Messages:
    138
    Location:
    Sag Harbor, NY
    2 Aug - 57' Beneteau struck by lightning

    First symptom - starter contacts sticky (burned out the starter!)

    Second sympton - 24v battery charger not working

    Third - 24v Alternator fried

    Fourth - No GPS, Radar, depth, autopilot, wind indicator, rudder angle indicator, SSB, Sat phone, navtex, stereo, windlass remotes down

    Fifth - Generator won't start (CPU burned out)

    My bad, didn't realize it was lightning until I had already replaced the starter, battery charger AND the alternator. As all other equipment is 24v and run through the batteries and as the batteries had completely died as there was no way to charge them, it wasn't until I had fully charged the batteries and found none of the equipment working...

    First I thought it was just a faulty starter. As I'm just minding the boat, I didn't realize the batteries weren't getting charged via the shore power or alternator for a few days.

    As the battery charger was brand new and didn't have a mark on it, I had to send it out only to find out it wasn't working and they didn't know what was wrong with it. I had a mechanic come who discovered the fried 24v alternator. It was his opinion that the alternator had gone bad (bad diode?) allowing the battery charger to go...

    Luckily, now that we know it WAS lightning, we'll be covered by insurance.

    Whew! As the bill is going to be a big one for all that!

    Photos of the exploded VHF antenna and one of the fried Sea Talk boxes.

    Attached Files:

  2. NYCAP123

    NYCAP123 Senior Member

    Joined:
    Mar 14, 2008
    Messages:
    11,205
    Location:
    Long Island, NY
    How did you get to looking for a bad starter if the batteries were dead? You should have gotten no starter click and the volt meter should have dropped. In addition I'd always try giving a suspect starter a wack while turning the key. No harm/no foul though since everything was fried and had to be replaced anyway.
  3. sagharborskip

    sagharborskip Senior Member

    Joined:
    Sep 7, 2008
    Messages:
    138
    Location:
    Sag Harbor, NY
    No, went to bring boat in from mooring to the dock just a day or two after strike - batteries were still charged. By the time I got to the dock, the starter was burned out (about 15 minutes run time).
  4. K1W1

    K1W1 Senior Member

    Joined:
    Sep 30, 2005
    Messages:
    7,388
    Location:
    My Office
    Hi,

    It sounds more like your starter failed to disengage and got burnt out by rotating for 15 mins, your batteries would have been supplying current all the time as well as the solenoid on a pre engaged starter won't release while the pinion is engaged with the flywheel.

    Did you see the starter opened up? Was all the solder thrown off the end of the commutator?
  5. sagharborskip

    sagharborskip Senior Member

    Joined:
    Sep 7, 2008
    Messages:
    138
    Location:
    Sag Harbor, NY
    No, didn't see the starter opened up and am just going by what the electronics tech said (I trust him implicitly as he's an electrical engineer who used to contract for the defense industry). By the time Al came to diagnose why I didn't have any electronics after having new starter, charger, alternator in place, when I mentioned the faulty starter, he said he'd seen a few lightning strikes cause starter problems.

    By the time we found the burnt out Sea Talk unit, coupled with all the failures happening at the same time (everything had been running perfectly til then), and having gone up the mast to find a non-existent VHF antenna, what else but lightning could have caused all this?

    I'm open to suggestions!

    When I took the alternator in for repair, the first thing they asked was, "was the boat hit by lightning?"

    I'm also open to suggestions as to what else to look for as a result of a lightning strike. I've got a diver coming tomorrow to look at all the through hulls, running gear, zincs, etc.
  6. NYCAP123

    NYCAP123 Senior Member

    Joined:
    Mar 14, 2008
    Messages:
    11,205
    Location:
    Long Island, NY
    There's not much I wouldn't be checking, including the terminus of all wires and grounds. Also check around the deck plates where the halyards are secured.
  7. sagharborskip

    sagharborskip Senior Member

    Joined:
    Sep 7, 2008
    Messages:
    138
    Location:
    Sag Harbor, NY
    Thanks, I also have a rigger coming to inspect everything close up...

    Cheers.
  8. sagharborskip

    sagharborskip Senior Member

    Joined:
    Sep 7, 2008
    Messages:
    138
    Location:
    Sag Harbor, NY
    Kiwi,

    What about exit point? If VHF antenna was entry point and the Sea talk box was melted, would there necessarily be a noticeable exit?

    Dan
  9. Castlerock

    Castlerock Senior Member

    Joined:
    Aug 30, 2006
    Messages:
    215
    Location:
    New England
    It had to exit somewhere, through hull fitting, ground plate, keel bolt, rudder post, prop shaft, look around and maybe have the boat hauled to be sure you are not missing something important.
  10. sagharborskip

    sagharborskip Senior Member

    Joined:
    Sep 7, 2008
    Messages:
    138
    Location:
    Sag Harbor, NY
    Thanks, bro...
  11. whybotherlol

    whybotherlol New Member

    Joined:
    Sep 21, 2008
    Messages:
    3
    Location:
    london
    run a dirty earth from the high point above last electronic fitting to a point of dispersal rudder bolt or something this will save any future burnouts and a crap load of money
  12. K1W1

    K1W1 Senior Member

    Joined:
    Sep 30, 2005
    Messages:
    7,388
    Location:
    My Office
    Hi,

    The exit will be via the path of least resistance, as Castlerock says there are many points where the charge may have exited.
  13. I was at the Stuart, FL Boat Show a few years ago and we had a thunderstorm. A bolt of lightning hit a radio tower next to the marina then hit a boat two boats over from the one I was on. I was leaning against the aluminum window frame, on the aft deck of a Hatteras MY when the bolt struck and I felt a shock in my arm.
    The next day I found out that all of my credit cards had been demagnetized by the lightning strike. I guess my wallet was the path of least resistance!
  14. K1W1

    K1W1 Senior Member

    Joined:
    Sep 30, 2005
    Messages:
    7,388
    Location:
    My Office
    Hi,

    That's not a bad story to tell ya grandkids.

    Have you ever noticed how your cellphone can wipe out the info on those Hotel Room Keys that use the magnetic stripe to store data but the same phones don't seem to goose your credit cards when in your pocket with your wallet, even when ya have 2 of them in the same pocket!!
  15. revdcs

    revdcs Senior Member

    Joined:
    Mar 30, 2007
    Messages:
    498
    Location:
    Fowey in Cornwall
    Hi K1W1,

    That's probably because the Hotel Room Keys have a 'lightweight' code recorded once onto the magnetic strip, which is designed to be erased so the card/key can be used again. The credit cards have the code permanently embeded into the strip not once, but dozens of times. This is to allow the stripe reader several chaces at picking up the code and also to ensure it can continue to be read if part of the strip is damaged or is worn down over time.
  16. CaptTom

    CaptTom Senior Member

    Joined:
    Jan 26, 2006
    Messages:
    1,949
    Location:
    Palm Beach to Ft Lauderdale
    That usually a guy's problem after a fight with the wife.
  17. Fishtigua

    Fishtigua Senior Member

    Joined:
    Jul 20, 2007
    Messages:
    2,937
    Location:
    Guernsey/Antigua
    Oh, you've met the bitter half?

    Fish ;)