Cotswold Archaeology and local divers hope to solve mystery of how the warship London sank off the Southend coast A major underwater rescue excavation is being mounted this summer by English Heritage to solve a 349-year-old mystery: how warship the London managed to blow itself up without firing a shot at the enemy, in broad daylight, within sight of the Southend seafront. Cotswold Archaeology and local divers hope to recover as much information as possible before the ship’s splinted timbers finally disintegrate.