Reversing Entropyvideo
This is How Lightning Strikes Sailboats !
June 25, 2025 · 12 min · 49K views
What this video covers
Paulo builds a tabletop Tesla coil experiment to test whether bonding a sailboat's mast to the keel reduces or increases lightning risk — the central disagreement between two schools of thought that Nigel Calder notes lacks sufficient scientific basis, prompting the ABYC to downgrade its bonding standard to an advisory bulletin.1:39
Three 3D-printed Hallberg-Rassy scale models represent different configurations: a wooden boat with no metal rigging, a keel-stepped mast bonded to the hull with metal stays, and a deck-stepped mast bonded to the hull with metal stays.3:09 A salt-water tub, grounded to earth potential, serves as the ocean.3:42 A small indicator lamp inside each hull detects stray current.4:06 Results: both bonded metal-mast boats attracted lightning cleanly to the masthead and conducted it to the water without stray current inside.5:05 The wooden boat was invisible to the Tesla coil arc until wetted with fresh water, at which point it became conductive and the interior lamp lit.7:45 An unbonded metal mast still attracted a strike but let current exit randomly through the hull, triggering the lamp.9:42 When a bonded and an unbonded boat sat side by side, lightning strongly preferred the bonded boat but struck the unbonded one occasionally.12:00 Paulo concludes that bonding attracts strikes but channels them safely, while an unbonded boat struck directly suffers interior current damage — and that neither option is clearly superior.12:09
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