What caused the Mary Rose to sink?

Its lifetime almost entirely mapped Henry’s dramatic reign. From the moment he assumed the throne in 1509, Henry had harboured ambitions to grow English power on the international stage. He soon sent out a message of aggressive intent by ordering the construction of two huge warships: the Peter Pomegranate and the Mary Rose.

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The following three decades were marked by bloodshed and diplomatic spats as Henry jostled with his European neighbours. Then, in 1542–43, tensions reached boiling point when he made a pact with the Holy Roman Emperor, Charles V, to go to war with France.

In 1544 Henry amassed a huge invasion fleet. But then came a setback: at the last moment, Charles backed out.

Henry’s troops were left abandoned at Calais, with little hope of taking Paris, so instead they successfully laid siege to Boulogne. It wasn’t long before King Francis I of France sought to avenge this defeat. And his attempts to exact that revenge would have fatal consequences for the Mary Rose.

When did the Mary Rose sink?

By 1545, the French ruler had assembled a 225-strong fleet of ships on the eastern end of the Isle of Wight, ready to invade England – and he planned to take Portsmouth first. With most of Henry’s men away defending his new territory in France, the king and his realm were in a vulnerable position. On 19 July, the French launched their attack.

During the afternoon, the vessel, part of an English fleet that was much smaller than its French counterpart, made its final manoeuvre across the Solent. The Mary Rose then sailed towards the French ready to engage and likely fired its guns, before turning to port and heading towards the shallow waters of Spitbank. It was then that it met its fate.

The battle of the Solent – as the clash between the English and French forces is known – raged on after the Mary Rose’s sinking. Following a series of naval skirmishes and fighting on the Isle of Wight, the French invasion was ultimately prevented. Yet, with Henry’s prized warship now lying on the seabed, a huge shadow was cast over the king’s moment of triumph.

So what doomed the Mary Rose? This is a question I’ve been discussing with a series of historians and maritime experts for a new podcast series, The Mary Rose: Secrets of a Tudor Warship. Here, I’ll explore six leading theories as to what sent the mighty vessel to the bottom of the sea.

Why did the Mary Rose sink? Six possible theories...

The only confirmed eyewitness account from onboard the ship comes via the ambassador of the Holy Roman Emperor, François van der Delft. In a letter to Charles V on 24 July 1545, he claims to share the testimony of an unnamed Flemish man “amongst the survivors” of the wreck, who stated that the Mary Rose “heeled over with the wind” and that “water entered by the lowest row of gun ports which had been left open after firing”. There is also archaeological evidence that the gun port lids on both sides of the ship were open when it sank. Could flooding and a sudden gust of wind have combined to set off a fatal chain of events?

If water flooding the gun ports was a risk, wouldn’t experienced sailors have known to close them? “In the heat of the moment, things do go wrong,” says Christopher Dobbs, one of the original diving team who helped salvage the Mary Rose. “Many people will remember the sinking of the MS Herald of Free Enterprise in 1987, where the bow doors were left open – unfortunately, sometimes it’s a case of human error.”

It’s also been suggested that, when it sank, the Mary Rose’s mainsail was upwards and flapping in the wind, leading those onshore to attribute its demise to unruly weather. However, according to geographer and battle of the Solent expert Dr Dominic Fontana, that was probably for good reason. “If you’re trying to stop a ship from sinking,” he says, “the first piece of advice is to stop. If not, more water is pushed into the ship.” Cutting lines to the sail, causing it to fly up the yardarm, was one way to do this.

While the Solent can be unpredictably choppy, the chances of a gust of wind being precisely timed and monumentally large enough to blow over a warship on a hot summer’s day is unlikely. Could the Mary Rose have been sinking for an entirely different reason already?

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The man in command of the Mary Rose that fateful day was Sir George Carew, an aristocrat who had been appointed vice admiral the day before the sinking. Carew was undoubtedly on good terms with Henry VIII but, according to some sources, he didn’t enjoy such warm relations with the Mary Rose’s crew. So could onboard tensions have contributed to the ship’s demise? One biography of George Carew’s brother, Peter, records how their uncle, Gawain, was passing by on another ship. Concerned by the Mary Rose’s unstable condition, he called to George, who replied, in alarm: “I have the sort of knaves I cannot rule.”

This claim of an unruly crew may have been made to protect the Carew family name. What seems certain is that the ship was chiefly manned by long-serving mariners (in fact, Peter Carew himself goes on to state how experienced they were). So it is possible that the crew may have simply ignored or gone against commands they disagreed with – for better or for worse.

Meanwhile, another theory is that the sailors were suffering from dysentery and were quite simply physically incapable of fulfilling their roles effectively.

There is also research that has suggested that because some of the crew probably spoke languages other than English, they didn’t understand the commands being given. In recent years, the remains of a group of crew members have been analysed.

“Taking a sample of around eight to ten, we discovered that two people were of African descent,” explains historian Dr Onyeka Nubia. “Finding even one such person would have shocked many people, but my conclusion is that perhaps between one and two thirds of the Mary Rose crew were non-English born.”

While it’s possible that some of the men didn’t understand English, it’s unlikely to be the cause of the sinking. After all, it was commonplace in the English fleet for crews of this time to have foreign mercenaries, seamen or even pilots on board.

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A few years after the sinking, Hall’s Chronicle reported that the Mary Rose “was laden with much ordinaunce, and the portes left open, which were low, & the great ordinaunce unbreached, so that when the ship should turne, the water entered, and sodainly she sanke”. To understand if this was likely, we have to look at the wider context. Traditionally, an English monarch would requisition vessels to transport men to fight land battles, but Henry was keen to build up his “army by sea” with a revolutionary new weapon: gunships. “This was really important for naval architecture, particularly the evolution of lidded gun ports,” says Christopher Dobbs.

These lids could be shut when not in use, so ships could sink lower in the waterline and house larger and heavier guns. However, the suggestion that the ship sank because its gun ports were too low has been discounted.

In 2007 it emerged that Henry had asked for heavy bronze guns to be positioned in the front of some of his ships, including the Mary Rose. In response, the ship’s master shipwright and surveyor observed that this would result in a “great weakening to the ship at this point”. This is exactly where the stem of the ship had separated from the rest of the hull. Had the Mary Rose been compromised by the king’s request?

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Or was the warship burdened with other weight? The captain’s brother claimed that there were as many as 700 men on board – an unusually high number to take into combat. However, the cook’s log included a detailed provision list for only 500 men. (A recent reassessment suggests we have the remains of 300 of these.)

The “heavy load” theory has sparked other suggestions. Sir John Oglander, a 17th-century politician, claimed that Henry VIII dined on the Mary Rose the night before the battle, and that when he left, all those on board rushed to one side to see him go. Untied ordnance slipped, unbalancing the ship, and water flooded in through the gun ports. Dramatic? Yes. Likely? No.

Despite the widespread belief that the Mary Rose sank on its maiden voyage, it had had a 34-year career beforehand that saw it travel many hundreds of miles, predominantly transporting troops and patrolling England’s coasts (including seeing off pirates). After so long at sea, it does seem unlikely that its design was the main cause of its sinking, especially as the Mary Rose had won much praise.

Following a brief stint as a warship, it took an unlikely role as Admiral Edward Howard’s racing yacht in 1513. He challenged his fleet to race around the coast of Kent, and despite being almost four miles behind some of the lead vessels at the start, the Mary Rose went on to win. The admiral praised his swift flagship in a subsequent letter to the king, calling it not just “the noblest ship of sail” but “the flower of all ships that ever sailed”. Perhaps he was flattering Henry VIII, but the Mary Rose’s capability clearly left quite an impression on the admiral.

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But even if it was shipshape early in Henry’s reign, this could have changed by the time it reached the battle of the Solent. In 1536–37, the Mary Rose underwent a major refit, adding extra gun ports and strengthening its sides so it could accommodate extra weight. However, these changes left the ship heavier, compromising the nifty sailing capabilities and manoeuvrability of its earlier racing days.

The Tudor vice admiral John Dudley certainly seems to have thought that at least some of Henry’s newly supercharged ships were “unweatherly”. Could these later modifications have altered the ship so much that it may have become vulnerable to the dangers lying in wait in the Solent?

One version of events theorises that, on the morning of 19 July, the Mary Rose was hit by its French foes some hours before it made its final passage. Martin du Bellay, a French cavalry officer who was present at the battle, stated that the French guns had ultimately been responsible for its sinking. But du Bellay’s account is contrary to all others, plus he was a close friend of King Francis I. It’s fair to wonder if he was falsifying claims of French glory over the English to justify what had become a failed invasion.

“There were certainly things going on in the hold of the ship, at the point when she sank, that would support the idea she had been hit,” argues Dominic Fontana. Later, skeletal remains revealed that several crew members had been working in the hold with carpentry equipment, such as hammers, at the time it had sunk. Though this was not a particularly unusual occurrence, it could have been that these men were mending a hole in the ship.

Those in command may not have been aware of such difficulties, because the ship could have remained upright and felt perfectly stable, even while water was coming in – at least, for a while. “One hundred tons of water would equate to about 18 inches of water in the bottom of the ship – that’s all,” explains Fontana. “It would look like even less when it was mixed in with the ballast. It would almost disappear, but it would have been fluid enough to roll the weight at the bottom of the ship.”

If the Mary Rose had been taking on water this might explain why it was heading to the shallows at Spitbank, one of the sandbanks near the harbour entrance, hoping to beach itself only several hundred metres away. Running aground would have been embarrassing, but not deadly.

While there is no direct archaeological evidence that can be attributed to even a modestly sized cannonball, only half the Mary Rose was salvageable. Could a French shot have simply hit the port side of the ship now lost to the sea?

Speculation over the years since the Mary Rose disappeared beneath the waves has ranged far and wide. “Over the centuries, historians have come up with many different reasons for what happened on 19 July 1545,” says Christopher Dobbs. “The sheer number of theories has proved a real problem when talking about the cause of the sinking.”

In reality, it is likely that a combination of factors had a part to play in the Mary Rose’s demise. “In most maritime accidents,” explains Dominic Fontana, “it’s a whole sequence of events that come together at a particular point, causing the ship to become overwhelmed by the circumstances.” However, we will probably never know exactly how these factors combined to doom the vessel.

“One thing is for certain,” says Fontana. “Henry VIII watched the Mary Rose sink, which is likely why there wasn’t an official investigation conducted into the cause.” In other words, Henry had seen all he needed to. But his lack of response has helped shroud the Mary Rose in a mystery that continues to torment researchers to this day.

The Mary Rose: Secrets 
of a Tudor Warship

In our new HistoryExtra podcast series, we’ll be marking the 40th anniversary of the raising of the Mary Rose by delving back into its fascinating history, and uncovering the secrets this Tudor shipwreck has kept hidden for more than four centuries…

Listen to the podcast series