The Mary Rose Redesign
Commissioned in 1511, the English ship Mary Rose was among the earliest vessels that relied on cannons, firing not from the top deck as had been the norm since guns were introduced to ships, but from portholes cut into the hull on lower decks. As such, she was among the pioneering ships that revolutionized naval warfare and helped usher in the transition from the age of fighting at sea via ramming, or grappling and boarding, to that of massed gun broadsides.
The Mary Rose was a success, and gave the Royal Navy decades of solid service, until 1536, when she underwent an unfortunate redesign and upgrade. The thinking behind the upgrade seems to have boiled down to “cannons are good, so more cannons are better“. It was not a bad line of reasoning in of itself but could prove problematic if more cannons were added to a ship that had not been specifically designed to accommodate more cannons and bear their additional weight. The Mary Rose was such a ship.
The redesign and upgrade entailed the addition of a new gun deck, and with the addition of more and heavier cannon, increased the ship’s weight from 500 tons to 700. That caused the Mary Rose to ride lower in the water, which in turn brought its lower deck’s gun portholes closer to the sea’s surface. The consequences played out in the 1545 Battle of the Solent, when the Mary Rose was among a fleet of English sailing ships becalmed in the Solent and unable to maneuver for lack of wind when they were set upon by a fleet of French rowing galleys.
The English fleet was in trouble, and the French galleys seemed on the verge of a victory over the immobilized English sailing ships, until the wind finally picked up. Sailing out in a stiff breeze, the Mary Rose led the English counter-attack, and the outgunned French galleys were the ones in trouble now. However, the Mary Rose’s first broadside caused her to heel or lean over to her starboard side, and her gun portholes, now lower and closer to the water’s surface thanks to the additional weight of the 1536 upgrade, dipped into the water.
The sea rushed in through the open gunports and the crew was unable to correct the sudden imbalance. Guns, ammunition, and cargo shifted to the submerging side of the ship, causing it to tilt even further, and the Mary Rose sank quickly, taking 90% of her crew with her.