When I was a kid I used to build model ships in 1/700 scale and so did my friends. Between the half dozen of us, there may have been 200 ships representing the battle fleets of WWII from just about every nation that put out to sea. We even had submarines that at that scale were about the size of a Salem 100 cigarette. Like fans do with their sports teams we would argue endlessly about which ships were the best, most heavily armed, or had the best armor among the world’s navies. We even adapted the rules for a naval board game called Victory in the Pacific that allowed us to use our model ships in mock combat. So it is with some satisfaction that I notice the popularity of games like World of Warships and dozens of other online warship simulators. It seems that the debate my middle school friends and I use to have about the ultimate gunfighting ship still goes on today, but now among grownups. And the most popular debate now is whether an Iowa Class Battleship could take on a Japanese Yamato Class Battleship and win.

That was also the most common debate among us as kids in the 1970s. In the Paleolithic Age of my childhood, there was no internet to consult. We would either scour the books we owned on WWII ships or hop on our respective BMX Mongoose (the BMW of kid-bikes in that ancient age) and ride to the local library. Huddled there around a table with 20 open books about ships, we’d quietly argue about armor belts, gun diameters, shell weight, and muzzle velocity while attempting to settle the question,

“Could an Iowa win against the Yamato?”

We never agreed.

It is a question I still wonder about even today, prompted in part by the debates I still see online about this enigma of enigmas among naval ship enthusiasts. After all these long years of study and questioning, I think I am ready to offer an informed opinion containing some points I’ve never seen anyone else offer. Probably because they haven’t contemplated the question for more than four decades as I have.


Why Does It Even Matter?

I guess it really doesn’t, but Mankind loves to ponder the possibles and impossibles. Americans tend to always think we do it the biggest and best, but in WWII Japan built the largest warship ever seen on the planet without competition until the U.S. Navy launched the nuclear-powered aircraft carrier USS Enterprise in 1961. Another reason may be that the four battleships of the Iowa class never got a chance to fight either the Yamato or her sister-ship the Musashi in a gunfight. In fact, none of the Iowa Class Battleships ever fired a single round at any battleship belonging to another county. Believe it or not, the same goes for the Yamato and her sister ship the Musashi.

The battleship USS IOWA (BB 61) fires a broadside to starboard from its Mk 7 16-inch guns.


Iowa Class Battleship Versus Yamato: The Stats

One of the reasons that the Iowa versus Yamato debate endures is that while we know quite a bit about the USS Iowa, there is a paucity of information about the Yamato. After the war, the Japanese burned a lot of their records to keep them out of allied hands, this included what was likely tons of paperwork on the Yamato class battleships. And since both Yamato and Musashi were sunk they can’t be examined up close. Even the third hull they converted to the unfinished aircraft carrier IJN Shinano was sunk, torpedoed by the sub-USS Archerfish as she was being moved between ports. For this reason, hardly anyone ever argues that Iowa was less than it was, rather, the argument is always that the Yamato was better than anyone thinks it was. But, I will be getting to that later.

So here are some useful stats to keep in mind.

                                                          Yamato                    Iowa

Gun Type and Calibre                18.1″/45 cal.             16″/50 cal.

AP projectile weight                   3219 lbs.                    2700 lbs.

Muzzle Velocity                            2559 ft/s                    2500 ft/s

Max Range                                     45,960 yards             42,345 yards

Rate of Fire                                   30 sec.*                       30 sec.*

Speed                                               32 kts*                         33 kts*


  • Rate of fire is approximate. At high gun elevation, the barrels have to return to loading angles of two-five percent and then return to their firing angle after the guns were loaded. Iowa was several seconds faster getting her guns down and back up to elevation than Yamato was. Iowa’s guns could elevate and depress at 12 degrees per second versus eight degrees for Yamato.
  • The speed of these ships underway would depend on the amount of weight each was carrying beyond their rated displacement. The Iowas carried a lot more fuel than Yamato did, and their cruising range was almost double that of the Japanese battleship. The USS New Jersey holds the record for the fastest battleship ever. In 1968, she reached a speed of 35.2kts and held that speed for six hours.
USS Missouri main battery plotting room
(U.S. Navy)


Iowa Had the Better Fire-Control System

At the beginning of the war, Japan had the best optically sighted fire control systems in the world. It not only employed very high-quality optics but carefully screened draftees coming into the navy for math skills and exceptionally sharp eyesight. If you tested well in either area you would find yourself in the gunnery plotting room on some ship in the Japanese fleet.  So within an optical line of sight, the Japanese were killing it, literally.

In the early war gunfights between ships in the Pacific, the Imperial Japanese Navy clobbered us repeatedly. One crucial thing to remember in this case is that the optical sighting system effectively limited the effective range of Yamatos guns. She could only hit what she could see on the horizon. The Japanese did adopt a radar/optical hybrid system later in the war but it was limited in range to about 27,000 yds or 15 miles which was still inside the visual range of the target. The Japanese radar could detect the bearing of an enemy vessel but could not estimate its range. In basic terms, it could tell them which way to look for a target in the dark or bad weather but range, course and, speed had to be determined visually. To compensate, the Yamato could carry floatplanes it could launch to provide aerial spotting and correct the firing solution for the guns.

In contrast, the U.S. Navy’s radar fire control system on the Iowa was putting out 30kw of signal energy. It could not only see well beyond the visual horizon but also provide the target’s bearing, range, course, and speed. In addition, the Iowas had gyro-stabilized guns in their turrets, and her fire control system could maintain a locked firing solution on a target and fire her guns even while maneuvering at high speed. Yamato could not do this: if she turned a new firing solution had to be worked out.

This means the Iowa, even though her guns had a shorter range than the Yamato, could fire her guns from thousands of yards beyond the visual range of Yamato’s optical fire control and pummel her. If Yamato turned to close the distance, Iowa could maneuver away with a slight speed advantage and keep firing with an accurate target plot because the U.S. Navy had the best vertical stability control systems for its gun mounts in the world. The radar was good enough to even detect the columns of water from shells that missed the target.

Yamato could extend her visual range by launching her floatplanes, but Iowa had three floatplanes as well, armed with machine guns. They would not have to shoot down the spotter planes from the Yamato but they could keep them too busy to send back accurate range and bearing information for her guns. Additionally, USS Iowa had 20 five-inch anti-aircraft guns with a range of more than 20 miles. Any Japanese floatplane that would come within that range would likely be shot down or be forced to stay so far off to be unable not provide useful spotting information to Yamato.

Can we tell how decisive this factor would be in a match-up between Yamato and Iowa? I think we can from the only two battles in the Pacific that had battleships slugging it out. At the Second Naval Battle of Guadalcanal, the U.S. battleship Washington punched it out with the Japanese battleship Kirishima in the dark of night. In an engagement that lasted only a couple of minutes, Washington fired about 75 of her 16″ rounds under radar control and hit Kirishima about 10 times, while her radar-controlled 5″ guns got 41 hits out of 107 rounds fired.  In contrast, the Kirishima using optical control, flares, and searchlights managed to hit the Washington’s accompanying battleship USS South Datoka only once with her 14″ gun main battery but missed Washington completely. In this battle, radar fire control allowed Washington to fire more rounds on target with vastly better accuracy. IJN Kirishima staggered away on fire and listing. She sank a few hours later.

Yamato bombed
Yamato maneuvers frantically under attack as a bomb explodes off its port side. The fire in the area of the 6.1-inch turret can be clearly seen. (Navy History and Heritage Command)

In the Battle of the Surigao Strait, the radar-controlled guns of the obsolete, pre-war battleship USS West Virginia fired at the IJN Yamashiro at 22,800 yds with her eight 16″ in the pitch black of night and hit her on the first salvo. This was beyond the visual horizon of the Yamashiro’s optical range detectors. She couldn’t even shoot back at anything but a gun flash beyond the horizon and was sunk.

Another major advantage Iowa enjoyed was that corrections of aim and elevation from the Radar Fire Control Directors were transmitted to the gun turrets automatically. Aboard the Yamato, these corrections were given by voice, which was a considerably slower and more error-prone method.

At the end of the war, the U.S. Navy’s gyro-stabilized guns and radar fire control systems were considered the best in the world, even better than the past masters of high caliber gunnery, the Royal Navy.

In a fight between Iowa and Yamato, this would be the most important factor. While Yamato’s guns could outrange the Iowa, she wouldn’t have been able to see her over the horizon, contrary to Iowa. In a fight between battleships, the side that detects the other guy first and lands the first blow tends to be the winner.


The Riddle of Steel

Japan was a relative newcomer in the science of building large capital ships like the Yamato. During WWI, her battleship fleet was built by the British, and the rest of her fleet was mostly built for them by the Brits, Germans, French, and Italians. In the years that followed, Japan would decide to build its own ships in a very rapid build-up of the Imperial Fleet. It had the third-largest navy in the world when WWII started.

Japan had no problem being innovative in its designs. Having no long tradition and accompanying doctrines of building warships the Japanese were very experimental. They built the first purpose-built aircraft carrier in 1921 and were the first to mount 14″, 16″ and, finally 18″ guns on their battleships. Their problem, though, was obtaining steel and fuel. Japan could obtain iron ore to make steel but Japanese coal was not very clean, making the steel brittle. She also lacked the rare earth metals used in high-strength steel production, like manganese, chromium, vanadium, molybdenum, and especially nickel.  Japan had a license to make Vickers Cemented Armored Steel from Britain but the nickel content and cost of fuel needed for the extensive manufacturing process was appallingly expensive to the Japanese who had to buy these materials on the open market from other countries.

So, while Japanese engineers were capable of making very high-quality steel in small batches, they did not have the money to build entire battleships out of it, or they certainly would have.

Therefore, Japan tried to come up with less expensive ways to make steel armor plates using copper instead of nickel. Yet, it’s important to recall that the Vickers Hardened Armor type she was using in her designs was WWI tech some 20 years old at that point. And while it was still pretty good armor up to eight inches in thickness it was very hard to get it to cool and heat evenly at greater thicknesses than that. Beyond eight inches it was found to be hard but brittle and prone to cracking.

In 1940 dollars the Yamato only cost about $2.5 million to build. In contrast, the Iowa class battleships cost about $100 million. It can be claimed that Yamato’s workmen made less money than American ship workers but it has to be remembered that Japan used 20,000 more tons of steel in Yamato than the U.S. used in the Iowa class battleships. That $2.5 million represents the sum total of all labor and materials, with some profit to the wholesale suppliers used to build the largest warship ever seen. I think the quality of the materials used is reflected in that $2.5 million number versus the “no expense spared” wartime building of the Iowa battleships at $100 million a pop.

To illustrate the point, whereas very expensive Special Treatment Steel (STS) was used by Western powers only on the interior armored boxes of a battleship to protect her vital innards like the engine rooms and magazines, on the Iowa, her entire armor belt was made of STS along with the armored citadel compartments shielding engine rooms and magazines. This was common to every battleship the U.S. made during the war.

The U.S. could afford to lavish virtually unlimited money on its battleships with the best armor made at the time. The Japanese could not and had to cut a lot of corners to even get the Yamato built.

Japan knew she could not afford the steel to match the U.S. and Great Britain ship for ship. It also knew it lacked the production facilities and raw materials to make armor plates as advanced as STS. So, it just made the Yamato out of the thickest Vickers method steel, although they did know that the thicker you made Vickers Hardened armor the more brittle it could become. In places where it really counted, like the upper armor of the turrets, they still used copper to replace scarce nickel but in small amounts.

They also had to cut some corners in other areas. For example, Yamato’s secondary anti-aircraft guns were the type 93 gun in 25mm. made under license by Hotchkiss in France. France had commissioned the design after WWI but had rejected this gun as too slow firing at just 110 rpm. Japan used a three-gun mount with a manually cranked platform. The gun director for the Japanese 25mm gun was just an officer pointing a stick at what he wanted them to shoot at.

By contrast, the American Navy used the Bofors 40mm on a four-gun mount that was electrically powered with an electro-optical director mounted on it and. The Bofors fired 240 rpm from each gun.

Eggheads on this subject get “lost in the sauce” going over tables, charts, and math formulas done by researchers after the war shooting rounds into armor plate captured from Japan and Germany, but I think they missed something very obvious, the Yamato and Mushashi were both sunk by aircraft armed with bombs and torpedos and not by 2,700lb, 16″ projectiles moving 1.500fps.

The planes that attacked Yamato and Musashi were carrying 500 and 1,000 lb bombs that came down pretty fast but nothing like the ballistic speeds that a battleship round travels at. The aerial launched torpedo that did the most damage to both ships was the Mk-14 torpedo. This had a warhead of just over 600 pounds and could travel at about 50 mph. On the other hand, a 16″ projectile could travel at 1,300 miles an hour.

The cost-cutting and relative inexperience of the Japanese in building large warships became obvious when Yamato was hit by a torpedo in December 1943 fired by the U.S. submarine Skate. The Yamato’s anti-torpedo blister failed to reduce the damage. An incredible 82-foot hole was blasted in her hull. She also experienced a structural failure on the joint between her upper and lower armor belts that opened a seam sending 3,000 tons of seawater flooding her after turret’s upper magazine. The explosive charge carried by the torpedo was only about 660lbs, yet, it still took months to repair her in dry dock.

The Musashi was probably hit by eight-nine torpedos and at least four bombs. The Musashi’s torpedo protection blisters also failed. The light aerial torpedos penetrated the hull of one of the two reputedly unsinkable battleships in the world, not once, but repeatedly.

Yamato met the same fate as her sister. She was attacked by aircraft on her way to Okinawa and was sunk by aerial torpedos she should have been able to brush off.

The remains of a piece of 26 inch Vickers method armor meant for the un-finishe third battleship in the Yamato class. a U.S. 16 inch battle ship projectile punched through it, cracking it in half.



After the war, the Navy obtained a front turret facepiece (photos above) from the unfinished Shinano battleship and fired a 16″ gun projectile at it, specifically, the 2,700-lb 16″ Mark 8 Mod 6 AP with inert filler (“BL&P”). This was the last battleship projectile design by the U.S. in WWII. The round was fired at very high velocity from a new barrel and hit at 1,992 fps. The results can be seen above. The plate fractured into two pieces and the shell created a roughly cylindrical hole as it passed through the plate. There was no damage to the projectile, which retained enough velocity to head out over the Potomac River and was not recovered.

Defenders of the Yamato like to claim that the Yamato’s thicker armor could not be penetrated by any gun. When they are faced with this cracked and holed plate of her very thickest armor they claim that the U.S. Navy “cheated” by using a new barrel and very high velocity at a simulated close range. To which I respond, “Well, which is it? Either it can’t be penetrated by any projectile or it can be if you cheat, both can’t be equally true at the same time.” What they miss is that the U.S. Navy was constantly improving its 16″ projectile and gun barrels during WWII, making them harder and tougher with the results you see above. The Mark 8 Mod 6, was the sixth modified version of the eighth design of a 16″ projectile that blew a hole right through the thickest armor ever put aboard a ship at sea. The U.S. Navy ended WWII with probably the best large-caliber armor-piercing projectiles ever devised. It can be surmised that while the Navy did have to boost the velocity of the Mk 8 Mod 6 round to utterly destroy the 26″ plate armor, the Yamato was not covered in armor this thick. This round at lower velocity and longer range would have punched through Yamato’s belt armor easily; we can assume this because we know the effect the slower and weaker aerial torpedos had on her.

While Japan lacked the resources to do continuous research and development during the war, the U.S. was constantly improving its weaponry and fire control systems. The development of the naval gun did not end with WWII. By 1950, the U.S. Navy had developed a cased projectile, auto-loading 8″ naval rifle that could fire an incredible eight rounds a minute.

IJN Yamato had decks that were only about nine inches thick and her sides were 16.” Here is why this matters: In another Navy test of the Japanese 26″ armor plate at a lower velocity of 1707 fps, the projectile penetrated more than 21″ into the plate and still opened a hole in it. Here is the remarkable part though: the projectile was undamaged except for losing its windscreen and armor-piercing cap, which it should have done. If the projectile had explosives inside, those would have projected through the hole creating a fatal overpressure to anyone inside the turret and killing them instantly. And again the plate cracked showing its internal brittleness under high-stress loads. The U.S. Navy engineers conducted extensive metallurgy tests as well and concluded that Japan’s Vickers Hardened armor was as good as anything the British had made during WWI.

Was this the best Japan could do with a piece of steel? No, because another piece the Navy tested was just 7.21″ thick. It was made most likely to Krup Steel specs they got from Nazi Germany. As it turned out, this piece of steel plate was the hardest steel the Navy engineers had ever seen. So, while Japan had the technical ability to make steel as good as any of the Western powers, in the case of Yamato they chose to go with an inferior quality because the really good steel was just too expensive. In the end, that armor couldn’t prevent an aerial torpedo from punching big holes in it.

This desire for economy may have also extended to the projectile design of Japan’s 18″ naval gun. This projectile was specifically designed not to penetrate thick armor but to plunge into the water and try to hit below the waterline of U.S. battleships where the ship’s armor would be thinner. In fact, Japan’s gunnery doctrine was to try and shoot a little short rather than over the target hoping for just that kind of hit. The Type 91 shell design was used in various sizes of Japanese naval rifles with only one known success in the entire war when an 8″ Type 91 shell hit the light cruiser USS Boise at the Battle of Cape Esperance in 1942. It didn’t sink her.

The U.S. Navy actually tested underwater shell designs, as well, but discarded them because they lacked the penetrating ability of armor plate above the waterline. There is good reason here to believe that in a match-up between an Iowa and a Yamato, her 18″ shells wouldn’t likely get a hit below the waterline of the Iowa. Also, there is good reason to believe that if Yamato’s underwater optimized and rounded-nosed projectile hit above the waterline it would not penetrate the Special Treatment Steel of the Iowa.


Crew Quality

During the War of 1812, the fledgling U.S. Navy with just a handful of frigates handed defeat after defeat to Britain’s Royal Navy, the largest in the world. The shot fired from American ships was prone to break up in flight coming out of the barrel and our gunpowder was not very good, but of approximately 17 single ship engagements the U.S. Navy won 14 of them.


It wasn’t that the Constitution and her sister ships were just better vessels, in fact, two of our six big frigates were defeated in pretty even fights. Rather, the deciding factors were the crews and their expertise in gunnery.

This comes into play in the Iowa versus Yamato scenario, as well. The Japanese were very good sailors and ship handlers in WWII, but when you look at the battle records of the Yamato and Musashi the picture emerges of a couple of Golden Calfs they were afraid to put at much risk. While the USS Iowa could be said to be “Haze Gray And Underway” nearly constantly the Yamato seemed to spend most of her time sitting at Truk or Kure naval bases as a floating hotel. She sat out the entire six months of the Guadacanal campaign at Truk as a flagship. The Japanese were afraid that inaccurate charts would end up seeing her run aground. They couldn’t find enough shells for her to do bombardment missions and she was such a fuel hog (burning 100 tons of oil an hour at flank speed) that she was just too difficult to send into a fight. As a result, the fighting ability of the crew could not be up to par when it came to the nearly constantly deployed Iowa class battleships that were escorting the fast carriers at battle stations for enemy subs and air attacks all the time.

Life could also be pretty harsh and austere on a Japanese battleship. After the numerous naval engagements fought Guadalcanal, the Japanese found they lacked effective damage control techniques as their ships would burn furiously when hit.  In an attempt to reduce the amount of flammable aboard their ships, mattresses were removed so the crews slept on planks that could be used to shore up bulkheads. There was also a custom in the Imperial Japanese Navy known as “standing in the line” whereby their officers would line up their enlisted men, berate them for the smallest mistakes, and then beat them with truncheons.

Crew quality is often overlooked in a debate over this match-up, but when we look at the battle record of these two ships, Iowa comes out with an advantage in having a seasoned, well-drilled, and well-treated crew with high morale and motivation.

USS Yorktown (CV-5) sinking, just after dawn on 7 June 1942, Damage control parties nearly saved this ship twice during the Battle of Midway. In the end, it took 6 bombs and 4 torpedos to sink this unarmored ship.


Damage Control

Without question, the United State surpassed any power in the world when it came to damage control. In battle after battle, U.S. ships could take heavy damage only to be saved by their crews and come back to fight another day. Take the USS Yorktown for example. During the Battle of the Coral Sea, Yorktown was hit by a 550lb armor-piercing bomb that penetrated four decks before exploding. Another near miss ruptured her hull plates and opened them to the sea. Yorktown had five area damage control parties dispersed around the ship and a whole ship roving party just to put out gasoline fires.

These crews put out the fires, stopped the flooding, and shored up bulkheads, therefore saving the ship. Returning to Pearl Harbor, she was partially repaired in 72 hours and sailed again to fight at Midway. In Midway, the ship was hit by three bombs and three near misses. Yorktown was left again smoking, flooding, and dead in the water. Within an hour, damage-control parties had the fires out, her deck patched, and her boilers relit. High-speed pumps dumped tons of seawater overboard. Yorktown again resumed flight operations at a speed of 25 knots. Later that afternoon she was hit again by two torpedos which threatened to sink her again. The damage control parties went to work a second time and managed to buy time for the crew to abandon the ship.

Still, Yorktown would not sink. The next morning, the captain asked for volunteers. The volunteers went back aboard the carrier, corrected her 26-degree list, were relighting her boilers, and were going to get her back to Pearl Harbor with a sea-going tug towing her when she was hit by two more torpedos fired by a Japanese submarine. Now, she was holed at her bottom, there was no saving her and she sank. The Yorktown was not an armored ship beyond splinter protection but her damage control crews did an incredible job. They did so well that it took six bombs and four torpedos to sink the unarmored aircraft carrier.

The U.S. Navy took damage control very seriously and devoted a great amount of training and resources to the crews. Further, it purposely designed vessels with ease of damage control in mind. The USS Yorktown, for example, could pump the gas in her aviation fuel pipes that ran under the flight deck back into the storage tanks when gas was not needed. This meant that if ruptured they would not pour burning gas into the hanger deck. She also had a water curtain system on the flight deck that would douse it in water with the push of a button extinguishing any fire that broke out, before it could explode planes and ordinance. Every member of the crew was trained in damage control.

Even today, every U.S. Sailor is trained in boot camp in damage control, shipboard, and even aircraft firefighting in case they deploy to carriers or air squadrons.

The Japanese had nothing like that level of sophistication in their damage control methods. They lost ship after ship to battle damage that might have been repaired if they had properly trained damage-control parties.

In our Iowa versus Yamato match-up having well-trained damage-control parties that can extinguish fires, get boilers relit, and restore electrical power after a hit would make a big difference in terms of staying in the fight and not just being a disabled and burning hulk getting pummeled by battleship gun projectiles.

Summing it all up, a battleship is made of more than just guns and armor, even though the USS Iowa was significantly outgunned and outranged by the Yamato’s 18″ guns, other factors decisively come into play, like armor and projectile quality, fire control systems, crew quality, and damage control abilities. Beyond the simplistic comparison of just shell weight and gun range, these factors would tilt the balance solidly in favor of the Iowa class battleships in a meeting with the Yamato.