The Incredible Engineering of the Diagonal Truss: WHY WARSHIPS BROKE THEIR OWN BACKS

A brand-new first-rate warship could sag by up to eighteen inches (about 45 cm) at the bow and stern before she ever fired a shot. The hull was breaking its own back under its own weight. This is the engineering of hogging: why a hull built from right-angled frames bent on every wave, why shipwrights hit a hard limit of roughly sixty metres, and why repairing a hogged ship could cost almost as much as building a new one. Then Robert Seppings borrowed the rigid triangle from bridge building, packed diagonal riders and iron straps into the hold, and won over a room of sceptical admirals with a single wooden slat. The real test came with HMS Tremendous, sent to sea for three years and measured again on her return. Sources quoted in the video: Robert Seppings' 1814 paper to the Royal Society, naval historians Brian Lavery and Peter Goodwin.