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In an alternate world of magic, a battleship similar in design to the Bismarck is stopped in the middle of the ocean. It was built by a society of Earth humans who moved to this world. All other nation’s technology is approximately from the medieval-renaissance era aided with a slight bit of magic.

Now, back to the ship. The massive battleship was dead in the water, probably because it was undergoing maintenance for its steam turbines.

On the horizon, a fleet of ships of the line appeared. The fleet noticed the massive grey silhouette in the distance and immediately moved to investigate it. The commander of this fleet saw the otherworlders’ battleship and thought to himself, “I want to conquer that.”

Obviously, the battleship crew had also spotted the fleet of ships of the line as there was a huge number of them.The captain, not wanting to waste ammunition, didn’t immediately obliterate them. Instead, he gave instructions to his crew to only fire at the ships attempting to board them.

The fleet of ships of the line realized death comes for whoever comes close to the massive steel whale. Instead, they decided to sink it from “afar”.

The fleet consists of about 700 vessels, they surround the battleship and broadside it until they run out of ammunition. The strategy of the ships of the line is similar to the land based musketeers, i.e. once the first group of ships of the line run out of cannonballs, they are replaced by the next batch of ships and so on. The battleship still won’t budge, not until its steam turbines are repaired which would probably take several more hours or perhaps even a day.

The problem is; the real battleship Bismarck also had impenetrable armor. It was still sunk by continued shelling from the battleship Rodney, battleship King George V and torpedoes from multiple destroyers. Some shells (the Rodney’s) did penetrate but most ricocheted off the hull. These ricochets made the hull red hot according to some sources.

I was wondering if maybe 24 hours+ of constant cannon fire will do the same.

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    $\begingroup$ Can you specify what you mean by ships of the line? If you are asking how long it would take the Spanish Armada to sink the Bismark, then the answer is never since even the smallest weapon aboard the Bismark outranged any weapon of the Spanish in 1588 AD. See Last Fight of the Revenge for similar circumstances and its surprising outcome. $\endgroup$
    – EDL
    Commented Mar 14, 2020 at 13:45
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    $\begingroup$ The feeble cannon of pre-modern ships of the line won't have any effect on a modern battleship except scratch the paint. (And pre-modern ships of the line could not hope to hit a target more than a few hundred meters away, anyway. At that distance even the auxiliary guns of the modern battleship will convert the attacking pre-modern fleet into driftwood.) $\endgroup$
    – AlexP
    Commented Mar 14, 2020 at 14:19
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    $\begingroup$ HMS Victory, Nelson's flag ship at the battle of Trafalgar, is still listed in the UK Royal Navy as a "first rate ship of the line". I assume the question is about a few hundred similar ships. $\endgroup$ Commented Mar 14, 2020 at 15:07
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    $\begingroup$ It is clear from answers and comments that even the anti-aircraft guns would be effective against an attacking ship close enough to hit the battleship. Do you have a reason for the captain to not expend a few thousand AA rounds discouraging the attack? $\endgroup$ Commented Mar 15, 2020 at 3:11
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    $\begingroup$ @Inthenameofthestory Apart from any camouflage or style benefits, a ship's paint serves a very important function in preventing rust and corrosion. Battleship armor plate is not stainless steel. $\endgroup$ Commented Mar 16, 2020 at 1:24

19 Answers 19

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Imagine for a moment finding a man in full plate armor — a veritable knight encased head to toe in steel — and ordering a few dozen men to attack him with aluminum baseball bats. What you'd end up with after a couple of hours (assuming the knight just stands there) is a whole lot of exhausted men with bent baseball bats, and a knight whose worst problem is the headache he has from all that ringing. Of course, you could order your men to aim at joints or the neck to damage the knight by pushing his armor against his flesh, but if the knight takes any minimal efforts to defend himself, that's not going to be effective.

This is the situation you'd have with a 17th century ship of the line attacking a WWII era battleship. The iron balls of cannon shot are too soft to penetrate steel of any reasonable thickness. It could aim for weak spots: concentrate all its fire at one single point in the hopes of creating a big enough dent to split a welded seam; lob shot down onto the upper deck (where the plating is thinest) trying to damage crew, infrastructure, or maybe hit a magazine. But again, if the battleship does any minimal thing to defend itself, getting close enough to do precision firing would be extremely problematic.

Honestly, all a battleship of that class needs to do is get its engines running. Even at quarter speed it can out-maneuver any ship of the line, so it could chase them down and run them over, no shots fired. I don't even want to dignify that act with the term 'ramming,' because a battleship would tear through a wooden warship and crush it like a bug. If your battleship crew had any sense, they would put cotton in their ears, raise enough of a defense to keep the wooden ships at bay, and focus all their efforts at regaining mobility. And when that's done, the fat lady sings.

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    – Monty Wild
    Commented Mar 18, 2020 at 6:26
  • $\begingroup$ The thought experiment about the knight and baseball bats s ridiculously flawed... $\endgroup$
    – fgysin
    Commented Mar 18, 2020 at 10:32
  • $\begingroup$ Given how persistently distracting the knight analogy seems to be, would it be better to make it about ‘throwing baseballs at a fully armoured knight’ instead? $\endgroup$
    – Pingcode
    Commented Mar 18, 2020 at 12:42
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    $\begingroup$ @Pingcode: No analogy is perfect, and there will always be people unwilling to suspend disbelief long enough to ge the point. C'est la vie... The virtue of this analogy is that it's evocative: it's easy to understand as a sincere effort to overwhelm a target, and gets across the idea that sheer numbers can't overcome certain qualitative technological advantages. I mean, does anyone attack anyone with baseballs? but attacking someone with a baseball bat is a cultural trope. $\endgroup$ Commented Mar 18, 2020 at 15:32
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During the War of 1812, the United States frigate USS Constitution earned its nickname "Old Ironsides" when cannonballs from HMS Guerriere were seen bouncing off its heavy all-wooden live-oak hull rather than penetrating.

In the mid-1800s, the introduction of ironclad and iron-hulled warships changed the nature of naval combat so quickly that many ships were obsolete as soon as they were launched. The HMS Warrior was an early steam-and-sail ironclad launched in 1860, with 11.4cm of wrought iron over 38cm of teak wood. It also carried 68-pounder guns and 110-pounder breechloading rifles, much more powerful weapons than HMS Guerriere's 18- and 32-pounder cannon.

Wrought iron is, by armor standards, extremely weak. By the start of the 20th century, 38cm of wrought iron was considered equivalent to just 14.6cm of the Krupp hardened armor steel available at the time.

Now, with another 30 more years of metallurgy behind it, the Bismark was built with an armor belt 22 to 32cm thick, with upper decks, superstructure, and turrets covered with anywhere from 5-12cm thick, plus armor up to 35cm thick protecting its conning tower.

You're specifying "late medieval-early renaissance". The famed Spanish Armada attacked England in July 1588, so let's look at that.

In the Battle of Gravelines, the English fleet attacked the Armada. In order to penetrate the hulls of the Spanish ships, they had to close to ~100 yards before firing their broadsides. They spent eight hours blasting away at the outmatched Spanish fleet, and when they finally ran out of ammo that afternoon, five Spanish ships -- out of over 100 -- were lost: four drifting aground and one sinking outright. Many other ships were severely damaged and the Spanish suffered ~20% casualties, but given how long and heavy the English assault was, it's pretty telling.

And why were the cannon so underpowered compared to the ships they were used against? Because the preferred tactic at the time was boarding. Part of the reason the Spanish were hit so hard in that battle is because they were focused on trying to board while the English were sailing circles around them.

So, you have a massive fleet of ships which need to be within shouting distance of their targets to have a chance at penetrating even ships of their own era, against one of the most heavily-armored ships ever built, using armor technology over 300 years more advanced. If they try to get within firing range, it will look identical to the "boarding action" that those ships are designed to perform and that the Bismark is worried about. And the Bismark has the problem that its guns can only depress so far; if it lets an enemy ship get that close, it's actually going to have trouble hitting the hull.

So each of those ships will attempt to close within their firing range and promptly receive a couple of 15cm or 10.5cm high-explosive shells at the Bismark's point-blank range (by which I mean like 2km), which will penetrate the hull like it wasn't there and do a gruesome amount of damage to whomever's inside.

Using one of the 38cm guns against those ships would probably be considered a crime against humanity. Assuming the fuse on the shell detected the impact on the hull of its target, you'd be hitting a ~40m long wooden ship with an 800 kg high-explosive shell -- "overkill" doesn't begin to describe it. (Just for fun, this explosion on Mythbusters is in the ballpark of one of those shells going off. Probably a bit smaller, actually.)

As far as heating up the metal -- the reason a blacksmith uses a forge is because hitting metal repeatedly doesn't heat it up at all. The shells that sunk the Bismark were explosive, so that energy is what was heating up the hull. Aside from heated shot, which weren't used aboard ships at that time you specified, cannonballs aren't hot enough to start fires or transfer heat to that degree. The hull might get hot to the touch at the point of impact, but you're talking tons and tons of steel sitting in a giant water bath; that's way to big a heat sink to get to red-hot temperatures through kinetic impact alone.

On the other hand, I hope everyone on board the Bismark has proper hearing protection!

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    $\begingroup$ Add to that: Battle of Hampton roeads which clearly showed that no modern gun of 1862 could penetrate the mere presence of 1 inch wrought iron point blank $\endgroup$
    – Trish
    Commented Mar 15, 2020 at 14:06
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    $\begingroup$ @Trish That battle did not show "that no modern gun of 1862 could penetrate the mere presence of 1 inch wrought iron point blank". Both sides had their armament handicapped. CSS Virginia was handicapped by only having explosive shells ("Trials showed that these rifles firing solid shot would pierce up to eight inches of armor plating."). While USS Monitor was handicapped by being ordered to use only 15lb of powder, rather than a full charge of 30lb ("trials found that a full charge would pierce armor plate"). Quotes are from here. $\endgroup$
    – Makyen
    Commented Mar 16, 2020 at 1:47
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    $\begingroup$ Plastic deformation does heat things up, but for most types of smithing, it isn't practical. This video shows platinum heating up under a power hammer though. $\endgroup$
    – AI0867
    Commented Mar 16, 2020 at 12:59
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    $\begingroup$ Note that, between the 3rd (wrought iron) and 4th (Bismarck) paragraphs, the armor thicknesses switch from being listed in cm to mm. So the Bismarck's armor was thinner than the previous paragraph's 38cm wrought iron, not 5.8 to 8.4 times as thick (in addition to being superior grade metal), as I initially (mis)read it. $\endgroup$ Commented Mar 16, 2020 at 15:21
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    $\begingroup$ @AI0867 ok that video is pretty nifty. Really, the issue with the scenario as described is that there wouldn't be nearly enough deformation in the armor to heat it. Platinum is extremely soft (especially when yellow-hot) and the hammer's moving it very quickly. Most of the energy transferred to the armor would be carried away as noise/vibrations, which would get bled off into the air and water. $\endgroup$
    – Salda007
    Commented Mar 16, 2020 at 22:25
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After the first dozen ships are destroyed with zero chance of causing even the slightest damage, the rest break off. Unless they are suicidal morons.

Seriously, they cannot damage the battleship and they get slaughtered in droves as they slowly approach what, to the battleship is point-blank range.

Hell, the Bismarck could probably win with just AA and machine guns.

EDIT: Bismarck's AA consisted of 16 105 mm guns in dual mounts, 16 37mm in dual mounts and 20 20mm in dual and quad mounts. I couldn't easy see what machineguns they had on board, but with a crew of over 2,000 I'm guessing they had at least a few dozen Mgs along with a larger number of rifles, sidearms etc.

Incendiary AA rounds would be extremely effective against wooden ships with cloth sails and plenty of loose gunpowder. Just fire a few bursts at each one until it brews up; you could probably sweep the deck clear of personnel.

For the crews, it would be like sailing into a conveyor-belt of death. I imagine a lot would abandon ship as soon as they saw what was happening.

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    $\begingroup$ An occasional 800 Kg shell landing anywhere near the ships would also be bad for morale. $\endgroup$ Commented Mar 14, 2020 at 19:06
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    $\begingroup$ They can't move. Preserve ammunition. Save the big stuff for dealing with the medieval armada if it doesn't get the hint. :) $\endgroup$
    – NomadMaker
    Commented Mar 15, 2020 at 5:48
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    $\begingroup$ Preserve ammunition, yeah. But as a single hit can kill a wooden ship, and probably more than one ship with high explosive and incendiary ammunition, and there was plenty of ammo for AA and machine guns, the ammo supply should be enough to kill every single naval vessel on the whole planet, multiple times. $\endgroup$
    – vsz
    Commented Mar 15, 2020 at 16:15
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    $\begingroup$ ... and don't forget the floatplanes. They could take off, and just bomb the flagship, killing the admiral and causing fear and chaos. Imagine the look in their eyes as they see that the enemy ship could kill them even from much much longer range than their cannons (which still can shoot at 10+ km, while the wooden ships barely a few hundred meters). Of course, the recon planes didn't have much armament, but 8x 50kg HE bombs would surely cripple a wooden ship. $\endgroup$
    – vsz
    Commented Mar 15, 2020 at 18:23
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    $\begingroup$ Don't forget that it was actually quite rare for a sailor on an age of sail ship to be able to swim. Abandoning ship would be unthinkable. $\endgroup$
    – Monty Wild
    Commented Mar 18, 2020 at 4:17
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Even a 32-lbr. gun could do serious damage to the superstructure and deck equipment of the battleship. Aircraft, aircraft catapults, ship's boats, radar and radio antenna, optical rangefinders, they would all be vulnerable to a hit. So unless you make the battleship captain stupid, he should fire back.

The Bismarck carried only 864-1,004 rounds for the 38cm guns and approx. 1,260 rounds for the 15cm guns, but there were supposed to be approx. 6,400 105mm rounds and approx. 32,000 rounds of 37mm, and even more 20mm. The 37mm and 20mm anti-aircraft ammunition included incendiary/explosive rounds, which should really inconvenience any wooden-hulled sailing ship with tarred rigging (aka a fire waiting to happen).


Follow-Up: There is a debate in the comments about how easy it is to trigger a fire or an ammunition explosion.

  • I'm not confident that a 20mm or 37mm FlaK could target the magazines. Imagine an autocannon shooting at a largish building, in the hope of hitting a specific room in the sub-basement -- except that you don't know where in the sub-basement that room is.
    While the gunner is trying to conserve ammo ...
  • A single round of incendiary ammunition may or may not start a fire. Give it a 10% chance of a fire that will not be contained by the crew, and a 10-round burst has a 2-in-3 chance of starting at least one such fire.

The attack maneuver you propose is also difficult for sailing craft. Sails would be reduced for fighting and speeds could drop to 2 or 3 knots -- call it 5 kph. The effective range of the muzzleloaders would be a few hundred yards, which is dangerously close to the "boarding range" that would definitely cause a reaction.

Regarding damage to the main hull from sustained fire, a third rate ship of the line would fire a broadside of 799 pounds. This compares to 2,048 lbs. for a single 16" shell from the HMS Rodney. But given the number of attackers you suggest, there might be repeated hits on the juncture of several armor plates, for instance.

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    – Monty Wild
    Commented Mar 18, 2020 at 6:24
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Let's look at it objectively:

You don't even need a battleship. Let's look at the first iron armored ships and their combat - which included frigates and 2 ironclads. The armament of both the frigates and the ironclads is comparable to somewhat superior to an age of sail ship of the line. USS Monitor and Merrimack/CCS Virginia in the Battle of Hampton Roads however showed what a mere 1 inch of wrought iron armor could do: Virginia got shelled by the Unionists frigates and wooden warships like crazy and suffered no damage. Monitor hammered away on Virginia and Virginia on Monitor and neither did do any damage to the other, not even dents at point-bank!

Now, you want to send a Battleship in. This battleship has multiple times the armor of these Ironclads and the ironclads hat better guns than a Ship of the Line! Taking the Bismarck Armor Scheme, the armor is 6.25 inches at the top deck and 12.5 inches of belt armor. Deck is 2 inches, impenetrable, and the whole ship was made from superior steel than the ironclads. The New-York Class has very similar armor and taking the Iowa Scheme, the Armada faces up to 14.5 inches or belt armor. Even the HMS Hood featured 6-12 inches of main belt armor!

But what about the superstructure? Well, the superstructure is, out of necessity to uphold the structure, made from at least half an inch of proper steel, which is roughly equivalent, if not superior, to zhe 1 inch of the wrought iron armor of the USS Monitor!

Conclusion:

No battleship can be even be dented or damaged beyond the finish with Ship of the Line armament. Atop that, the cannonballs only deliver kinetic energy, while the Rhodney did shoot both much heavier and much larger ammunition that was either Armor Piercing or High Explosive. Without such large ammunition, heating the armor to any glow is impossible. The battleship at best looses its paint, and once it can raise steam, it just steams away, turning any ship of the line that is in front into driftwood.

Much more likely, the commander would observe the armada, pinpoint the flagship, and then sink that, and the ship of the vice-admiral, with 2 shots using secondary or tertiary armaments. Beheaded, the armada would have to see that there is NO safe area within miles.

What if...

Now, let's amp up the ante and replace Bismarck with Musashi: Captain Kaoru Arima spots the armada on the horizon. He has the fire control radar crew trail in the fleet sailing in a rather close formation. He decides to spend 6 shells per volley, one from each gun of the forward facing main batteries. The barrage of 6 times 46 cm (18.1 in), trailed in with the fire control radar over some minute, is launched with about 6° elevation. We start the battle-clock.

T+0:0:15 - The barrage of 6 shells reaches 10.000 meters and is some dozen meters above the waterline. Because he saw wooden ships, Capitan Arima ordered to load sanshikidan - combined shrapnel & incendiary anti-aircraft ammunition. The shrapnel is distributed in a 20° Cone from the detonation point, ripping through sailors, sails, and ships, further setting ships and sails ablaze with impunity. The zone of destruction for each shell is about 1 kilometer long and 350 meters wide at the end of the cone - and the 3 guns of each turret are aimed with sightly different points of impact (staggered to be about 500 meters from one another) for a total zone of destruction of twice 44080 m² (8.2 American football fields). ANY ship within these ~16 football fields is practically destroyed, and that at the expense of the most useless ammunition Musashi has abroad! In tight formation, that would be between 25 and 50 ships hit.

T+0:00:45 The second barrage is launched, aiming a few degrees more port and starboard.

T+0:01:00 second barrage sets another 16.2 football fields ablaze before the enemy fleet even has had the chance to even react by setting any signals. The first ca. 20 ships following up on those already set ablaze run into the floating and burning wrecks as they can't maneuver quick enough, suffering damage. Total number of disabled ships is between 70 and 120 at this point

T+0:01:30 Third barrage launched, distance to the armada is still very close to 10 kilometers.

T+0:01:45 Third barrage hits. Following my estimate, between 16 and 27 % of the armada has been disabled. If the rate of destruction is kept up, the armada will be wholly ablaze between T+0:08:15 and T+0:12:30. By this time the Armada sailing at 6 knots would have managed to close in towards 8.5 km/7.5 km - or several miles outside of their engagement range.

Note that he could have started fire at 25 kilometers and still most likely hit his target, 10 kilometers is guaranteed hit area for Musashi (and maximum range for the anti-aircraft ammunition), and anything below about 2500 meters is pretty much elevation 0 for the main armament.

The secondary armament of 15.5 cm guns has a depression angle of -7° and is mounted at about 15 meters above the waterline. It can hit ships at their waterline starting at 122 meters - which is closer than the effective range of the ships of the line, meaning any ship trying to get that close gets immediately sunk, either by an armor-piercing shell cleanly ripping through the boat twice, starting to flood it or by a high explosive load of 50 kg blowing up the ship's hull and the magazines.

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    $\begingroup$ You're understating the damage done at Hampton Roads. The Monitor had some pretty impressive dents in the turret, while the Virginia had severely cracked armor (and not just from Monitor's guns -- Cumberland and Congress both managed to get in some good hits, just never enough in any one place). $\endgroup$
    – Mark
    Commented Mar 15, 2020 at 23:04
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    $\begingroup$ I don't think Musashi would be the worst possible opponent these ships-of-the-line could come across, either. A fully upgraded Iowa-class would not only be eating their lunch BVR with radar or spotter-guided cannon fire, but would be targeting any HVTs it could identify (with the help of the onboard recon drone, mind you) with guided anti-ship missiles -- the 200+km range of the AGM-84 means that there is literally nowhere for the proposed foes to hide or run to. Never mind the US Navy's mastery of damage control... $\endgroup$
    – Shalvenay
    Commented Mar 15, 2020 at 23:24
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    $\begingroup$ @Shalvenay : I doubt they would use guided missiles, they are in much shorter supply than gun shells. Maybe they would use one for demonstration purposes, and keep the rest for targeting cities if they have to stay on that planet for extended time periods. $\endgroup$
    – vsz
    Commented Mar 16, 2020 at 6:14
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    $\begingroup$ Does radar reflect off wood? I don't believe it does, but if it doesn't, the radar may see just the metal inside the armada, which isn't much and which isn't what radar and radar operators were prepared to detect. Of course, the armada would be spotted visually anyway, so this merely a nitpick. $\endgroup$
    – toolforger
    Commented Mar 16, 2020 at 6:53
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    $\begingroup$ The radar would definitely ping off the cannons, and might get returns from various fittings throughout the ship... but yeah, nothing like the return from another modern warship. $\endgroup$ Commented Mar 16, 2020 at 17:10
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If I was the battleship's commander, as soon as the 700-ship fleet of sailing vessels shows up on the horizon I'm altering my orders. "Only vessels which are closing on our ship are to be targeted. Each of the 105mm gun mounts will be assigned targets in its quadrant of the ship. Any enemy vessel closing to eight kilometers range will be targeted by two rounds of 105mm high explosive and two rounds of 105mm white phosphorus and results observed. If an enemy vessel closes to six kilometers range the 150mm battery on the side of the ship that the targeted enemy vessel is on will open fire, firing in groups of two rounds with time allotted after firing to observe results. If any target closes to five kilometers range it will be engaged by the main battery. Ammunition is to be conserved, and firing on disabled targets is not permitted".

In other words - if they stay far enough away to be no threat, we won't shoot at them. It they get too close they'll get a warning shot. If they keep coming we'll hit them with smaller stuff, and escalate as needed. In a rational world, one ship might close to seven kilometers, but I expect the results - that the closing ship was set on fire and blown to pieces well beyond the range where the guns of the fleet could even hope to reach the battleship - would be sufficient to dissuade other captains. If for some reason the fleet decided to attack from all directions simultaneously - well, I expect the gun crews on the battleship would be busy for a time, but once there is a wall of burning/destroyed ships around the battleship it'll be tough for any undamaged ship of the fleet to get through. I doubt that any would be able to close to even long cannon shot (roughly 2 km).

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  • $\begingroup$ Won’t using the main battleship guns over-penetrate the wooden hull of ships of the line? $\endgroup$ Commented Mar 15, 2020 at 8:05
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    $\begingroup$ @Inthenameofthestory for wooden ships, overpenetration is just as deadly as explosion: they have no compartments. If aimed close to the water line, the whole ship will sink. If aimed higher, you shoot pretty much over the deck or through the mgazine - one of the two detonates the ship. $\endgroup$
    – Trish
    Commented Mar 15, 2020 at 14:02
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    $\begingroup$ @Inthenameofthestory - somehow I think that a 15" shell blasting clean through your ship would send the appropriate message. But remember, the sides of wooden warships were thick - 20 to 30 inches of oak. Contacting that plus whatever was struck inside the ship would be sufficient to detonate the shell. $\endgroup$ Commented Mar 16, 2020 at 15:40
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    $\begingroup$ Unless you're doing it for humanitarian purposes or show of goodwill, don't do warning shots. It wastes ammo. The warning is at least just as good when you're trying to hit, and may be much better. $\endgroup$ Commented Mar 16, 2020 at 15:50
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    $\begingroup$ @EmilioMBumachar - good point. Orders altered. :-) $\endgroup$ Commented Mar 16, 2020 at 15:53
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Taking just the energy side of the question: say we're using 36lb (17.6kg, we'll round up to 18kg) guns. These have a muzzle velocity of ~450m/s, apparently. That means that the kinetic energy in each shot no firing is ~1.8MJ. Assume that's all perfectly applied to the ship. The armour of the Bismarck weighed 17.5Mkg, so rather conveniently, that's about 0.1J/kg per shot. Steel has a specific heat of around 420 J/(kg°C), so each shot raises the temperature by at most 0.00024°C, so it needs ~4,200 shots to raise the temperature by one degree.

Suppose we've got some uprated monster of a ship with 100 of these on (the largest ships to carry them had 32, plus a bunch of smaller guns). That means that we need 84 broadsides to raise the temperature by one degree. If you've got the ships lined up bowsprit-to-stern and moving at 5kph, assuming that your ships are 200m long (a bit shorter than real ships of this many guns), you can get off 25 broadsides per hour, so it will take a bit over 3 hours and 20 minutes to raise the temperature by one degree.

However, the target is also going to be shedding that heat to the surrounding water. If we get it 0.015 degrees above ambient, each square meter of surface is going to be chucking out heat at ~0.67W (using this calculator and doubling it because we're only actually doing half of that transfer).

Now, assume every single cannon ball is hitting that same square meter. The total input power is 1.8MJ/shot * 50shots/broadside * (25 / 3600)broadsides/second = 0.625W.

That is: we'll never raise the temperature enough to measure, even locally, even if every single shot hits the same point.

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The Bismarck wouldn't put up with it for one second

They would use any means to repel the attackers.

Remember how the Germans lost the Graf Spee. The damage they took in battle was trivial - the British attacks barely dented the armor. However, every battleship has some squishy equipment topside - radio masts, rangefinders, lifeboats, and on the Graf Spee, the fuel purification system that pre-processes bunker fuel for use by the diesel engines. This was a bolt-out-of-the-blue critical hit that doomed the battleship.

So, you do not let yourself get beat up. If a Viking ship is shooting arrows at you, you sink it. If a USCG patrol boat is shooting off its .50 cal at you, you sink it. You just never know what is going to happen in war, and you do not give the enemy a chance to get a critical hit.

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    $\begingroup$ Added to this, a heavy anti-aircraft machine gun (not even a cannon with explosive shells, just 12mm or so solid bullets) could sink a 16th century "ship of the line". AA cannon could do it with just a few shots. $\endgroup$
    – Zeiss Ikon
    Commented Mar 17, 2020 at 13:39
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Let's rephrase your question:

"We have a battleship with hard iron plating being hit with slow lead projectiles. What weight of accumulated projectiles is necessary before the battleship sinks?"

Lots. Also, they would better with some occasional chain shot to make a more cohesive mass.

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    $\begingroup$ Lead balls are unlikely. The standard balls were iron once it was possible to cast them, and stone before. Not that cast-iron balls had a big chance to penetrate battleship armor, either. $\endgroup$
    – toolforger
    Commented Mar 16, 2020 at 7:00
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In order to deliver damage, a projectile mush have

  • suitable velocity
  • suitable hardness

Velocity is needed to give enough energy to the impact, and hardness to ensure that the target is damaged.

A battle ship contemporary of the Bismark would be able to afford shots with both characteristics.

A ship dating centuries before would fail on both sides: soft and slow projectiles would keep hitting the target.

I don't have hard number for a more sensible answer, but I think those ships have no chance of making any real damage to the target, unless they manage to consistently hit always the same point, which is practically impossible.

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    $\begingroup$ Not to mention that if the pre-modern ships come close enough to be able to hit the battleship, the smallest auxiliary guns of the modern ship will destroy them with ease. $\endgroup$
    – AlexP
    Commented Mar 14, 2020 at 14:21
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    $\begingroup$ But will the constant impacts heat up the hull? I mean, all that kinetic energy surely needs to go somewhere, right? $\endgroup$ Commented Mar 14, 2020 at 14:56
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    $\begingroup$ The hull of a metal ship is effectively water-cooled. The total kinetic energy would not do much when it comes to heating up an ocean. $\endgroup$ Commented Mar 14, 2020 at 15:02
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    $\begingroup$ @Inthenameofthestory, Re, "All that kinetic energy..." Yes, but if the hull is not dented by the shot, then very little of the energy will go toward heating it. Steel, if you don't permanently bend or dent it, is highly elastic. It "gives back" most of the energy of an impact. Some of that energy will be given back as sound waves that will be dispersed throughout the ship and the water and the air. Another portion will be given back to the shot itself--crushing it, shattering it, sending it back in the direction from which it came. $\endgroup$ Commented Mar 15, 2020 at 13:25
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No, the sailing ships cannot sink the battleship using their cannon.

But...

Once the battleship is moving again, they could lay partly submerged ropes across the path of the battleship in an attempt to tangle the battleship's rudder. The sailing ships wouldn't know about the propellers unless there was some divination magic that revealed their existence and importance, but if the propellers were adequately entangled then the ship would be immobile until divers are able to clear the props. Note that there is absolutely no need to prevent the propellers from spinning, despite what several people seem to think in comments. If enough debris gets wrapped around the propeller then it stops being a propeller and becomes a spinning pile of trash. Put simply, if water cannot flow through the propeller then it will not provide any thrust for the ship no matter how freely it is able to spin.

It should also be noted that the blades of a propeller will absolutely not cut through a rope. Despite being called "blades" they are not sharp and exert no cutting force. If a rope gets caught by a spinning the propeller it will simply wrap around the propeller and propeller shaft until it is either completely wrapped up or until the rope catches on something too difficult to move and the tensile strength of the rope is exceeded.

If the battleship were to sail over a partially submerged wreck of a recently sunken ship, the sails, rigging ropes and many busted up pieces of wooden masts and spars can get caught on the propeller and wrap around it. This debris will reduce the performance of the propeller and slowing down the ship.

If the sailing ships could then keep enough pressure on the battleship that the props could not be cleared, or if any other method can be found that immobilizes the ship, then the battleship's stores of food and fresh water become a very critical factor in which side wins this contest. This scenario does not require the ship's speed to literally be brought to zero. It only requires that the ship's movement be reduced in a manner that will prevent it from reaching a source of fresh water and food. Even if only one propeller is significantly reduced in performance and the other cannot be used at full power otherwise the ship will be moving in circles.

The ships of the line don't need to defeat the battleship. They need to defeat the battleship's crew.

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    $\begingroup$ Aren’t the hydraulic systems of the battleship strong enough to break a measly rope? $\endgroup$ Commented Mar 15, 2020 at 0:23
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    $\begingroup$ @Inthenameofthestory Depends on the quality and quantity of the rope. The props are not driven by hydraulic systems. The rudders probably are, but that should have no impact on the actions of the sailing side since they don't even know what hydraulics are any more than they'd know what a propeller or a steam engine are. But they would understand that ships have rudders and that disabling a rudder is a very effective tactic against a naval vessel. $\endgroup$
    – krb
    Commented Mar 15, 2020 at 2:53
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    $\begingroup$ Nice idea, but I doubt the ships of the line could get close enough to pull this off without being sunk. $\endgroup$
    – toolforger
    Commented Mar 16, 2020 at 7:03
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    $\begingroup$ The rope is almost certainly going to get severed as it drags against the hull of the ship; if it doesn't, it's going to get chopped to pieces by the propellers. If you're very, very lucky, some pieces will wrap themselves around the rudder and keep it from moving, but the ship can still steer by differential throttling of the engines. Forget about trying to stop the propellers -- those are able to chop through driftwood, whales, or renaissance-era ships of the line without trouble. $\endgroup$
    – Mark
    Commented Mar 16, 2020 at 23:35
  • $\begingroup$ Bismarck's propellers (had 3) are nearly 5 meters tall weighing several tons the force plus the cavitation created will literally disintegrate rope even if you had rope long enough to actually wrap around it multiple times. Rope is not gong to do anything either of the 10 ton rudders (it has 2), it took a direct torpedo hit to even disable the mechanism. this is not a poorly made commercial craft it is designed to be incredibly robust mechanically. $\endgroup$
    – John
    Commented Feb 26, 2021 at 16:56
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For the Iowa class the citadel has enough reserve buoyancy to keep the ship afloat if the rest of the hull is flooded. The the side armor is 12.1" sloped at -19 degrees.The transverse armor is 11.3" There is no way, no how a cannonball is getting through that.

Before the cannonball could even get to that armor it would have to pass through 2" of armor plate that was not even counted as "armor" at the hull.

For comparison, the CSS Virginia had a maximum of four inches of armor (not face hardened)that the 11-inch cannon of the USS Monitor could not penetrate at point blank ranges.

In the mean time, the Iowa's have 500 rounds per 5-inch gun (10,000 rounds) and 1264 rounds of 16-inch projectiles; any one of which could sink a wooden ship on its own.

The 40mm guns could also do hull damage to a wooden ship. The 20mm guns could keep an opponent's heads down low.

The effect would be a lot of dents.

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The Bismarck carried supplies for less than 3 months, so that's how long it could sustain the attacks.

The canon fire doesn't matter.

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he gave instructions to his crew to only fire at the ships attempting to board them.

Your commander may not be able to fire at ships which are attempting to board his vessel, at least not using his guns: Battleships are tall and the guns can only be depressed a limited amount. For example, the 20mm Oerlikon guns on an Iowa class battleship could typically be depressed to 15 degrees. I can't find out where those guns were mounted, but the deck is about 50' above the waterline. So a 20mm gun mounted on the deck could not target anything closer than about 180'. If the guns were mounted higher in the superstructure, then the minimum range is larger than that.

I didn't get numbers for any of the larger guns, but I would guess that the bigger the gun, the larger its minimum effective range. Battleship were designed to shoot targets that were many miles away.

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    $\begingroup$ Even if they cannot use the larger weapons at such close range, they don't need to. German sailors would be able to sweep the decks of the sailing ships with small arms fire, saving the heavy weapons for times when they are more needed. $\endgroup$
    – krb
    Commented Mar 15, 2020 at 0:01
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    $\begingroup$ Musashi had 15.5 cm guns with -7° elevation, which could fire at the waterline about 150 meters away. $\endgroup$
    – Trish
    Commented Mar 15, 2020 at 13:57
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    $\begingroup$ Any reason anyone would wait to fire after it gets closer than 180'? I'm no sailor, but presumably the intent to board is clear far before then. $\endgroup$ Commented Mar 16, 2020 at 15:53
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    $\begingroup$ @EmilioMBumachar The OP specified this: "Instead, he gave instructions to his crew to only fire at the ships attempting to board them." For ships of the line, their intent to board will only be evident when they come inside the minimum range of the battleship's guns. 180', or 150 meters (various distances for minimum range) are the distances at which ships of the line could fight when they are not attempting to board. $\endgroup$ Commented Mar 16, 2020 at 15:57
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    $\begingroup$ That same 50-foot deck height makes it quite difficult to board the battleship. From the typical renaissance-era ship's deck, you've got a 30-foot climb before you can start fighting. $\endgroup$
    – Mark
    Commented Mar 16, 2020 at 23:42
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Though the question specifically asks about the fire-power exchange of these vessels, there is another important factor that has yet to be mentioned: Freeboard. The freeboard, the distance from the water-line to where you'd want to board, on the Bismark was 18 feet at its lowest, simply due to the size of the ship. (see: https://www.bismarck-class.dk/technicallayout/generaldetails.html)

While earlier ships designed for boarding had high freeboard to provide a better boarding defense/offense. By the time "ships of the line" were in service, ships became less tall and more elongated. While this difference in elevation is not insurmountable, it is less than encouraging.

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    $\begingroup$ Ships of the line depended on broadside firepower, which was roughly proportionate to the area of one side of a ship. They needed multiple decks far enough above the water to permit gun ports. $\endgroup$ Commented Mar 17, 2020 at 20:44
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About 2 weeks:

Because the ungodly noise of dozens of cannonballs per second pinging off the hull and superstructure of the Bismarck would make enough noise so that no person on board could sleep.

2 Weeks is about the upper bounds for how long a person can stay without sleep before they go completely insane and scuttle their own ship, just to end the infernal din.

Damage to Bismarck? Possibly some windows. The hull armor was some 220 to 320 mm thick Krupp Cemented Steel, cannonballs hitting that would simply fragment, not leaving even a smudge.
The upper desk and superstructure was armored from 50mm to 180mm depending on value and vulnerability. Even the thinnest 50mm Krupp Steel would shrug off a point-blank broadside with no more than minor surface denting under 1mm deep.

Windows, Humans, Small firearms that are exposed would be vulnerable.
The main cannons, including AA class cannons would be invulnerable.
(maybe the 40mm AA cannons could be hurt with a direct hit on the mechanism)

Counter-attack:
Ammo be damned!
The Bismarck could likely sink any attacking Ship of the Line with a single burst of AA shells. A 10.5cm flak cannon would quite possibly sink a wooden ship with ONE round. The Bismarck had SIXTEEN of those, with a total of 12000 rounds of ammunition for them.
It also had sixteen 37mm rapid-fire AA guns, with 32000 rounds of ammunition. These would not sink a ship of the line with one shot, but a salvo of 20 rounds would make 20 * 10cm holes in the wooden ship's hull, and kill a large part of its crew by (wooden) shrapnel.

Remember that for the ships-o-line to fire at the battleship, they would need to be close. Their cannon are only effective from point-blank out to about 1000m. This is so close to the Bismarck that they might have difficulty aiming the main cannons, due to the artillery tables not including such short ranges!! But the Secondary guns ("only" 15cm guns firing 45kg high-explosive rounds) and the AA batteries and guns would have a jolly old time.

Bismarck likely has enough ammo, in total, to sink 10 000 wooden ships of the line.

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  • $\begingroup$ probably not a single round from a flak cannon, you can actually punch quite a few holes an a wooden ship before it sinks, one of the up sides of building a ship out of a buoyant material. Flak cannons could easily kill the entire crew before sinking the ship. $\endgroup$
    – John
    Commented Feb 26, 2021 at 16:31
  • $\begingroup$ @john a 10.5cm naval flak cannon shoots an explosive round proximity(useless) and impact-fuzed. It contains about 12kg of high explosive, and shoots out 3kg of shrapnel at supersonic speeds. It will shred a mere oak-beam wooden vessel. I'm pretty sure a 3-m radius hole in its hull will more than inconvenience a ship-o-the-line! $\endgroup$
    – PcMan
    Commented Feb 26, 2021 at 18:16
  • $\begingroup$ @john yummy detail info here: navweaps.com/Weapons/WNGER_41-65_skc33.php and here(not exact model, but nice projectile specs and cutthrough) navweaps.com/Weapons/WNGER_41-45_skc32.php $\endgroup$
    – PcMan
    Commented Feb 26, 2021 at 18:31
  • $\begingroup$ inconvenience sure, sink in a timely manner not nessisarly, as I said the flak cannon could easily kill the entire crew before the ship sinks. A flak cannon is going to have have a hard time hitting a wooden ship low enough to punch a large hole below the water line, even then wooden ships unlike steel ones don't sink that fast. Ironically if the flak cannon does enough damage to the bottom it might not even sink that day if the ship looses its ballast. It won't be fighting but it may not sink either. It is a question of using exactly the wrong tool for the job. $\endgroup$
    – John
    Commented Feb 26, 2021 at 19:44
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I expect a very different outcome here:

The armada approaches, the commander of the battleship realizes they're facing a bunch of people who have no idea of the degree of mismatch of the firepower. The captain wishes to preserve ammunition. Thus he will do a variation on the traditional shot across the bow--he will drop one shell into the water in front of the flagship of the armada. I expect the armada would quickly surrender or depart. If they do neither the second round obliterates the flagship. I would be very surprised if anyone else steps up to command an attack.

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    $\begingroup$ This is the sensible result, of course. But the OP has specified that the battleship Captain is batshit insane, because he prefers to just sit back and allow them to attack, unless they try to board. Normal insane would not suffice for this, it requires batshit insane. But OP can set the scenario as OP wishes, and we try to accommodate out answers to match. $\endgroup$
    – PcMan
    Commented Feb 8, 2021 at 6:36
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I agree with other answers that a barrage of cannonballs would have little effect. However, if you are looking for a story that allows the sailing ships to win, consider

Stealth boarding at night

This scenario would be especially effective if...

  • The initial battle happens during or near nightfall of a moonless night.
  • Whatever causes the battleship's engines to fail also knocks out the ship's electrical power, making searchlights and lighting unavailable.
  • After failing an initial battle, the remaining sailing ships retreat and regroup. They devise a plan to wait a few hours, then rush the battleship with boarding parties.
  • Expecting the battle to be over, most of the battleship's crew goes to bed for the night. Only a small crew is left on night watch.
  • Because the sailing ships make practically no sound and there is little natural light, they are able to slip close to the battleship undetected.
  • Casualties are heavy on both sides, but the sailing ships are able to win by overwhelming the battleship's crew.

I'm not claiming that the sailing ships would always win, but if you want a scenario that gives them a chance, here it is.

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    $\begingroup$ All the battleship crew has to do to hold off the boarders is close and dog the watertight doors leading inside from the deck. They're solid steel, a half inch or more thick. Nothing the pirates can bring up a boarding ladder will get through those within a single night. $\endgroup$
    – Zeiss Ikon
    Commented Mar 17, 2020 at 13:45
  • $\begingroup$ Also, unless the battleship crew left a climbing net or ladder hanging over side, the boarders will have to come across from the yard-arms; the battleship deck will be several meters above those of the ships of the line. $\endgroup$
    – Zeiss Ikon
    Commented Mar 17, 2020 at 13:46
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    $\begingroup$ I have not been able to find actual dimensions for the height of the poop deck of a ship-of-the-line, but my impression was that HMS Victory's is about 18 feet above what was the waterline. She has three decks of cabins under her poop deck. For boarding, one would try to tie up with the highest deck of the attacking ship next to the lowest deck of the ship being boarded. $\endgroup$ Commented Mar 17, 2020 at 20:36
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    $\begingroup$ "Because the sailing ships make practically no sound and there is little natural light" nope, sorry. I'm sure the seven searchlights of the battleship will be used quite actively to scan the surrounding waters, on the night after a fleet attacked it in the first place. ALSO, the Bismarck's three radar sets would easily see the masts of approaching ships. German radar at that time could pinpoint a torpedo ship at range from 500m to 15000m with ease (and bombers out to 230km). Ship of the line masts and crows nests include a lot of metal bands and rivets, making it shine like a beacon to radar $\endgroup$
    – PcMan
    Commented Feb 7, 2021 at 12:36
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The other answers here are fundamentally misunderstanding a very important factor:

The opposing force vastly outnumbers the battleship.

700 ships, assuming each ship can bring 30 cannon to bear on the target, is 2100 cannonballs. Assuming one in twenty hits, that's still 105 rounds per salvo slamming into the hull or the deck of the ship. 105 rounds of 36+ lb shot traveling at almost 500 meters per second.

Repeated impact stress of that magnitude will slowly shake the ship apart, even if not a single shot penetrates the hull, not to mention anything on deck will absolutely be obliterated by massed cannon fire.

To be clear, the conflict still weighs heavily in favor of the bismark here - it's armor is substantial enough to take that beating for a significant amount of time and a single shot from basically any of it's armaments could sink any of those ships.

But, it does not have an infinite amount of time to leisurely sit and absorb cannon fire from 700 ships of the line while doing nothing. Eventually, something will start to give, and those ships carried enough ammo to continue firing for many hours.

The Bismark will need to fight back.

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    $\begingroup$ Using that logic, if one empties enough magazines of automatic rifle fire at a tank, one will shake the tank apart. How many tanks are you aware of that have been shaken apart by rifle fire? $\endgroup$ Commented Mar 16, 2020 at 20:13
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    $\begingroup$ Using your numbers for the size, speed, and accuracy of the salvos, that's about 2 MJ of energy hitting the ship every salvo. That's equivalent to a half-kilogram of TNT, or about four 20mm antiaircraft shells. It's less stress than the battleship will absorb just from plunging through the waves in the average storm. $\endgroup$
    – Mark
    Commented Mar 16, 2020 at 23:50
  • $\begingroup$ @KeithMorrison I mean, yes, absolutely, given enough bullets and time. At some point the massed fire is basically a sandblaster. You'd erode the thing. It's about as practical as attempting to use erosion to dismantle a tank, which is to say, very much not. Also not very practical is turning 2100 cannon to fire on a single WW2 era battleship, but I'd bet sinking that ship is quite a bit easier than reducing a tank to dust via sustained ablation. $\endgroup$ Commented Mar 17, 2020 at 15:00
  • $\begingroup$ @Mark Yes. Storms sink ships. For this reason. $\endgroup$ Commented Mar 17, 2020 at 15:01
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    $\begingroup$ With enough cannons firing at the Bismarck, they could easily defeat it. By delivering enough cannonbals to make an artificial shoal under its hull, and grounding the battleship! Not a practical solution, to be sure, but... $\endgroup$
    – PcMan
    Commented Feb 7, 2021 at 12:28

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