Lightning Finds Its Way

by Bruce Landsberg
S/V Southern Comfort #1881
Deale, MD

Thankfully, we weren’t aboard Southern Comfort, our 2000 Catalina 36, when she was hit by lightning at the end of August 2009. According to slip mates, a series of heavy thunderstorms rolled across the western shore of Chesapeake Bay and the resulting sparks made it look like a welder’s convention. Nobody actually saw the strike – prudent, given the forest of aluminum masts that provided great grounding paths. Four other boats on our dock were also damaged including some low-to-the- water powerboats.

Two days after the storms, while visiting the boat, I noticed that the stereo wasn’t working. Gotta have tunes when on the boat! Further investigation revealed a lengthy list of inoperative electronics but little physical damage: The tip of the VHF antenna, a slight burn mark in the depth meter display, and the electronic bilge pump switch which had been blown apart. When powered up, many components had that instantly recognizable burnt insulation smell. Some perhaps mistakenly believe that fusing will prevent destructive lightning strike voltages from wreaking their havoc.

Within three days the boat was hauled and inspected for underwater damage. There was none. Catalina’s use of Marelon seacocks eliminated another path to ground. Southern Comfort is never plugged into shore power when we’re not aboard to reduce the potential of galvanic corrosion and power surges from lightning strikes on the grid. Nice idea, but lightning finds its way.

The benefits of grounding have been debated for years and the Catalina 36 is not grounded. Steve Russell, our surveyor, participated in an extensive research project years ago to settle the issue. It didn’t. Various systems might or might not make a difference and there seems to be little statistical evidence, one way or the other, that I’ve come across. At least one of the other damaged boats on our slip was fully grounded. Lightning finds its way – grounded or not.

It’s eye-opening the number of electronic conveniences we add to our boats. The minimalists will agree and the rest of us would be well advised to have good insurance. The “butcher’s bill,” to use the British royal navy term for casualties, was extensive: every exterior light - anchor, steaming and position lights, the VHF antenna, everything on the pedestal - speed and depth meters, wheel autopilot, chartplotter, battery charger, stereo, VHF radio, battery monitor, tank monitor including the sensors on the tank and the electronic bilge pump switch. It’s amazing that boats once sailed without any of this! Everything with a microprocessor/ circuit board on the DC side was toast. Interior DC lighting and the refrigerator were fine. The AC system was untouched as was the relative low tech and robust world of electric marine plumbing. The final tally was just shy of $12,000.

While there are many horror stories in the boat support world, I have high praise for Boat U.S. Insurance, the surveyor and the installer, Marine Technical Services at Herrington Harbour. They did their job professionally and kept me advised on the status throughout. Observations: Invest in good insurance if your boat is electronically well-endowed, and as for grounding boats - perhaps there’s more to learn. Lightning finds its way.

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