Practical Sailorvideo
What Happens When Lightning Hits a Sailboat?
March 28, 2026 · 9 min · 61K views
Sailboat heeling as lightning strikes nearby in storm
What this video covers
Lightning strikes on sailboats involve 20,000 to 50,000 amps of current seeking the fastest path to the water.1:07 When a mast lacks a low-resistance grounding path, the electrical discharge often creates side flashes, arcing through wiring harnesses, engine blocks, fuel tanks, or the hull itself.2:37 These side flashes can blow holes in fiberglass, destroy electronic networks, or cause mechanical failures like fused throttle cables and shattered rudder posts.3:59
Effective lightning protection requires creating a direct, low-resistance highway for electricity from the mast base to the water, typically using heavy copper conductors connected to the keel or dedicated grounding plates.5:29 Sharp bends in these conductors increase resistance and the likelihood of arcing.6:17 While bonding systems for corrosion control often use wires too thin to handle lightning, dedicated lightning grounding systems utilize heavy-gauge materials to maintain electrical potential across metal components.7:00 Disconnecting antenna cables and shore power during storms helps mitigate induced voltage damage, while avoiding contact with rigging or lifelines prevents personal injury during a strike.7:29
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