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World War II: Naval Ship Types

World War II battleships
Figure 1.-- The battleship was the naval capital ship at the onset of World War II. This changed over in a few hours when the Japanese launched a carrier ttack on Pearl Harbor (December 1941). Not only did the attack demonstate the stunning strike capability of carriers, but all of the Pacific Fleets battleships were sunk. Admiral Nimitz had to design naval operations arond the three carriers he still had. This is the 'USS Iowa' after the War in San Franciso Bay (1949). The six Iowa class battleships were 45,000 tons, the first American bsttleships were the new World War II era battleships whose design was not encumbered by treaty limitations. They were designed to be fast battleship that could keeo up with the Essex-class fast carriers. Their roke was to protect the carriers from Japanese bsttleships and as anti-aircraft platforms. They began to reach the fleet (1943). A larger Montana-class was designed, but the War ended before they were complete. Only four of the Iowas were delivered. The Japanese surrendered underneath the big guns of the 'USS Missori' guarded by Fkletcher-class destoyers.

At the onset of World War II, navies were ranked in terms of capital ships, meaning battleships. Naval technology and tactics during World War II, however, evolved around two areas that none of the navies thought to be critical before the War--carriers and submarines. Battleships became a ship type of only secondary importance, essebntially floating gun platforms to protect the carriers. And an entirely new class of ship rapidly developed--the landing ship. The Americans and Japanese in the Pacific had both planned war winning fleet action, all based primarily on their big-gun battleships. Both countries developed fleet air arms, but it was widely believed that the expected fleet action would be decided by battleships. The core of the Japanese battleship force was the massive Musashi and Yamato. Each had 18 inch guns which could outrange the 16 inch guns of the American battleships. The importannce of carriers was not understood before the outbreak of the Pacific War. While the carriers made the headlines, each of the different vessel types played important roles. Destroyers were multi-purpse vessels, including pritection for the fast carriers. Cruisers provided big-gun support in situations when battleships were not available. The battleships were the floating gun platforms to pulvdrize beach dfenses and for anti-airctaft fire to break up Kamakazee attacks. Submarines played an impirant role in the war. Most accounts focus on the U-boats who ultimtely failed. Unlike the Americans, the Japnese did not use their sizeable sumarine force in a commerce war.


The battleship at the onset of the War was regarded as the capital ship type by most naval strategists and the public, the primary measure of naval power. Battleship construction before the War was affected by naval arms traties. A related ship type was the battle cruiser, essentially a poorly armored battleship. The most famous was HMS Hood. Most British were outfitted with either 14 inch or 15 inch guns. The American battleships built before the war mostly had14 inch guns and they were followed by the newer Iowa class of battleships with 16 inch guns. Most German pocket battleships had 14 inch guns but their two main battleships, the Bismarck and the Tirpitz had 15 inch guns. The Japanese also went through a series of battleships with guns getting bigger with each new design culminating with the Yamato-class. Both of the two ships built had the largest guns ever put on a ship. Theywere 18.1 inch guns. Just a hit by one shell could blow a destroyer in two if it hit in the right spot.These 15, 16 and 18 inch shells usually had more then 2,000 pounds of explosives in them. And had a range of 20 to more then 25 miles. [Military History] At the onset of World War II, navies were ranked in terms of capital ships, meaning battleships. Naval strategy was built around these ships. Naval technology and tactics during World War II, however, evolved around two areas that none of the navies thought to be critical before the War--carriers and submarines. The new fast battleships and smaller ships were assigned the role of protecting the carriers. Older battleships were relegated to softening up invasion beaches.Battleships became a ship type of only secondary importance, essentially floating gun platforms to protect the carriers. Despite the emergence of the carrier, the Japanese devoted huge resources to build two super battleships--Yamato and Musashi. The Imperial Navy planned to build 13 of these massive ships. The Americans and Japanese in the Pacific had both planned war winning fleet action, all based primarily on their big-gun battleships. Both countries developed fleet air arms, but it was widely believed that the expected fleet action would be decided by battleships. The core of the Japanese battleship force was the massive Musashi and Yamato. Each with 18.1 inch guns which could outrange the 16 inch guns of the American battleships. The importance of carriers was not understood before the outbreak of the Pacific War. Building massive ships with huge guns made sence before the rise of naval airpower. With carriers, these huge ships simply became large targets and their construction meant that many more useful smaller ships were not built.


The British Royal Navy invented the aircraft carrier as a realistic naval weapon in the closing months of World War I. A major problem the British face, like navies in time immerorial, was finding the enemy fleet. The HMS Furious was launched with a a reconnisance mission (March 1918). It was a converted cruiser. Planes had no trouble taking off. It took some time, however, to develop landing techniques like arrestor wires. Other navies followed the Briotish lead after the War. A contributing factor was the Washington Naval Treaties (1921) which placed limits on capital ships (battleships). Conversion to carriers was a way of saving ships that otherwise would have to be scrapped. Naval warfare changed fundamentally during World War II. Even after the War began, the battle ship was seen as the capital naval vessel. Admirals foresaw fleet actions with big-gun battlehips. Carriers were seen as fulfilling scout and reconiance duties. The Btitish carrier attack on Totanto attracted some attention (November 1940). The sinking of the massive Bismarck also atracted attetion (March 1941). But it was Pearl Harbor that fundamentally changed naval warfare. Within minutes after thie commencement of the Japanese carrier the naval concepts were alterd forwever. Some naval visionaries like Yamaoto and Halsey had seen this change coming, but the naval establishments until Pearl Harbor had seen big-gun battleships as the backbone of a naval force and the ships that would settle major fleet engagements. The Japanese carrier attack on Pearl Harbor changes this concept in 2 hours by sinking or destroying the eight battleships of the American Pacific Fleet (December 1941). There were still Amerivan admirals who wanteda battleship fleet action, but as he American batteships rsted on the bottom of Pearl Harbor, Admiral Nimitz's only option was to base a war plan around the Pacific Fleet's three carriers. The Pacific War, the largest naval conflict in history, would be dominated by the carriers and their air compliments. The Americans and Japanese in the Pacific had both planned war winning fleet action, all based primarily on their big-gun battleships. Both countries developed fleet air arms, but it was widely believed that the expected fleet action would be decided by battleships. The importance of carriers was not fully understood before the outbreak of the Pacific War. Virtually instantaneously, the Pacific War became a carrier war. The United States Navy, even the big gun battleship devotees, had no option, but to base naval operations on the Pacific fleet carriers which survived the attack. The United States Pacific fleet with its battleships sunk, had to adopt a brand new strategy relying on the carriers that avoided the Pearl Harbor attack. And the success of the attack convinced the Japanese that the carrier had become the new capital ships. Four of the Japanese carriers executing the Pearl Harbor attack were sunk at Midway. June 1942). The American carrier Enterprise was involved in the Midway victory and the major Pacific campaigns. Midway as followed by a naval slugfest around Guadlcanal in which America and Japan lost carriers (August-November 1942). It was the arrival of the Essex-class carriers that fundamenally altered the naval balance (1943).


Carriers were also affected by naval arms treaties before the War. There were both heavy and light carriers. The heavy cruisers were essentilly small battleships. The German pocket battleships were basically very heavy cruisers with especially large guns. Light cruisers commonly had 6 inch guns while heavy cruisers usually had 8 inch guns. A country could only build so mny battleships because of the huge cost of construction. Cruisers were smaller and less expensive as well as more maneuverable. Thus they could be employed for actions in which battleships were either unavailable or unsuited. They allowed a navy the ability to project naval power over a larger area than was possible with the relaively small number of battleships available. It was British cruisers that conducted the first important naval action of the World War II tracking down the German pocket battleship the Graf Spee in the South Atlantic. Important battles were fought by the traditional ship types primarily because carriers were at first often not available. This proved to be the case in the Solomoms because the existing carriers were sunk or put out of action. Cruisers and destroyers were left to slug it out in the restricted waters of the Solomons. And the Japanese cruisers performed burillintly, nost notably in a night action around Savo island off Gudalcnal, arguably the greatest defeat in American naval history. (Peal Harbor was essentially an air defeat/) The heavy use of cruisers was also the case in the Mediterranean because the British had so few carriers. The naval actions in the Sollomons Slot mostly involved cruisers and destroyers. There were many excellet cruisers built and deployed during the War. The excellent Japanese cruisers and well drilled crews performed well at the beginning of the Pacific War, but could not ovdrcome the lack of radar as it was deployed on American ships.

Destroyers and Escort Craft

Destroyers first appeared in World War I,although precursors date back to the late-19th century. They had light guns, but armed with torpedoes they could destroy much larger ships like cruisers and do great damage to battleships. The United States and Britain built large numbers of destroyers in World War I,in part to deal with the U-Boat threat. The U.S. Navy did little to improve destroyer technology after Woirld War I. The Japanese on the other hand built a substantial fleet of modern destroyers. The German builkt a small, but excellent destroyer force. With the outbreak of Worlkd War II, the British suddenly needed destroyers. The British Royal Navy needed destroyers and covettes in large numbers, both for fleet operations and escorts in the Battle of the Atlantic. The United States provided mothballed destroyers in the Destroyers for Bases deal. American destroyers were used for an undeclared war in the North Atlanic before America entered the Wr. The Royal Canadian Navy of mostly destroyers and corvdttes was virtually built from the ground up to escort the Atlantic convoys. The Japanese introduced their 'special type' destroyers more than a decade before the War began. They were thus at ghe time the Pearl Harbor attack oropelled America into the Pacific War, the most modern and largest destroyers in the Pacific and played an important role in early Japanese victories, both in the Dutch East Indies and the Solomons. The Germans had some excellent destroyers, but most were lost in the invasion of Norway which subsequently weakened the Kreigsmarine's ability to support the planned Operation Sea Lion invasion. The American answer was the Fletcher-class destroyer. They began reaching the fleet after Midway (June 1942). It was a large flush-deck 2,100-tonner. It rapidly became the back bone of the American destroyer fleet in both the Pacific and Atlantic. The Fletchers evebn plsyed z key role in the D-Day landings. The most important naval campaign of the War was fought in the North Atlantic against the German U-boats which were defeated by a combined effort of the U.S. Navy , the British Royal Navy, and the Royal Canadian Navy. Destroyer esorts were developed for convoy duty and jeep carriers provuide air cover in the mid-ocean gap. By World War II they were multiple purpose ships doing patrol and escorts duties. All of navies had destroyers. The initinal idea of protecting capital ships and convoys was greatly expanded. The United States in addituin to the Fletchers deployed large numbers of destroyer escorts which played an important role as pickets protecting major fleet operations.


Submarines became key players in both the Pacific and Atlantic. Several navies, including the Germans and Japanese had major submarine forces. The only successful submarine campasign, however, was fought by the U.S. Navy in the Pacific. With the outbreal of World War II in Europe, the Germany Kreigsmarine again unable to match the Royal Navy, again launched a commerce war. The Royal Navy had underestimated the submarine which they concluded had been made obsolete by ASDAC (SONAR). This proved not to be the case, at least until moder effective SONAR was developed. Admiral Dönitz, head of the German U-boat fleet, developed innivative Wolf Pack tactics that threatened to accomplish what the U-boats had failed to do in World War I. Prime Miniter Churchill wrote after the War that it was the U-boats that caused him the greatest anxiety during the war. Britain was not, however, the only industrialized island nation that was vulnerable to a sunmarine-based commerc war. Japan was even more dependant on imported food and raw materials than Britain. This was a vulnerability the Japanese did not attach much importance to when they launched the Pacific War. It would be the United States that would conduct the only successful submarine campaign of the war. It was not until years after the War that historians learned how important the American codebreaking effort was to the American success. Had the Japanese not surrendered (August 1945), the faced mass starvatiion in the winter (1945-46). Unlike the Americans, the Japanese did not use their sizeable sumarine force in a commerce war.


Gunboats were widely used in the late-19th and early-20th centuries by European navies, primarily to support empire. They could move upriver in areas where it w not possible to move artillery over land. They were not of great use when confroning other European powers, but vry effective in confroning poorly armed colonial insurgencies. Gun boats did not have the big guns needed in naval warfare. The most famous gunbotof the war was the USS Panay, sunk by the Japanese as theylaunced the invasion of China (1937). Hot heads in the militry were all for taking on the United States as well as China. It created an interntional incident, but the militarists that dominated the Japanese Government backed down, at least for a time. Japan's intent was, however, all too clear. And it further blackened the Japanee image in America. The vulneability of the gun boat as aaval wepon as clearly shown. And there was no compensating attributes like speed and effective weaponry. And as a result, gunboats did not play a major role in the War.

Motor Torpedo Boats (MTBs)

Motor Torpedo Boat (MTB) was new class of naval vessels which appeared in the run up to Wlorld War II. MTB was the designtion given by the British Royal Navy to fast torpedo boats. The 'motor' in the MTB designation referred to the gasoline (petrol) engines which were used rather than the steam turbines or reciprocating steam enginesused on larger naval ships. MTBs were small craft and thus called boats rather than ships. In some ways they replaced gunboats, but actually were radically differnt as hey were not equipped with artilleru, but did have guns. But they we true naval vessels because they had the offensive punch to take on even major naval vessels. The destroyer had been created before World War I as way of delivering torpedoes in a naval battle. This gave a very small, but highly maneuverable assettg the capability of destroying a major enemy target, even a capital ship. The MTB took this a step further. The MTB was essentially a torpedo launcher without a ship attached, although the additions of guns allowed it to serve many other purposes such as patrol and interdiction. The potential of the MTB was shown when German E-Boats encounteted American landing craft traoning for D-Day. The best known MTBs were the American Patrol, Torpedo (PT)-boats in the Pacific. Unlike the Royal Navy nesination, the U.S, Navy used a hull frather than engine clasifucation. With the damage to the Pacific fleet at Pearl Harbor, the U.S. Navy had to adopt innovative tactics, and for some time one of the few resources was a hanful of PT-boats in the Ohilippines. They were dployed in greater numbers in the Solomons and played a critical role there before the arrival of larger ships. They were, however, highly vulnerable craft. PT-boats were made of plywood. his made them easy to build, a huge advantage in the first year of the War, but very vulnerable. One historian describes what happend to the nost famous PT-boat of the War--the PT-109 commaznded by furure president John F. Kennedy. "The [Japanese] destoyer struck the PT near the forward machine gunstation and sliced throuhh the boat at a sharp angle. The sound of cracking wood suddenly pierced through the night. The starboard side of the 109 was sheared off from a point near the forward torpedo tube all the way aft, and one of the engines was knocked away. Flanes shot through the air in a brilliant explosion as the boat's high octane gasoline ignited from a ruptured fuel tank." [Domagalski]

Landing Craft

An entirely new class of ship was developed during World War II, during, not before -- the landing ship. Some new vessel types emerged during the War, including PT-boats and a variety of landing craft. But most of the vessels types existed before the War. Landing craft at the outset of World War II were not much different than those used in the 18th century. They were not a specialized type--just small boats carried aboard naval vessels. Landing craft had nothing of the breath-taking drama of a navy combat ship. But after the German Western Offensive (May June 1940) and the Japanese Pacific offensive (December 1941-May 1942) it became clear to the American and British that to win the War, amphibious operations on a massive scale would be needed. Up until that time there were no real purpose built landing craft. The Germans did not need them like the Allies, but early on the lack of such craft caused problems. Using destroyers resulted in huge losses when they inaded Norway (April 1940). There was a push to build landing craft to invade Britain -- Operation Sea Lion (September 1940). There answer was jerry-rigging Rhine River barges. Hardly suitable for the Channel. This may have resulted in disaster if Hitler had actually ordered the invasion. The lack of landing craft caused huge losses during the Crete invasion. And was a factor in the failure to invade Malta. The Japanese basically used craft like the classic Boston Whaler. These boats could deliver men, but not heavy equipment. This would sufice becuase they were attacking poorly defended colonial outposts. After Midway (June 1942), the easy invasions ended. And a major reason the Japanese failed at Guadalcanal (August-November 1942) was their inability to land supplies and heavy equipment. And the Marines on Guadalcanal almost failed because of the inability to quickly land heavy equipment and supplies. Clearly if the Allies were going to launch successful amphibious operations, innovative landing craft would be needed. The Dieppe Disaster made this crystal clear (August 1942). Fortunately shipyards in the United States were already churning out what was needed. This was done mostly in America. British shipyards were fully engaged buiding and sevicing Royal Navy vessels. The two most famous of these craft were the Higgins Boats carrying assault troops ashore. The other was the Landing Ship Tank (LST). The nost important amphibious landing of the War (Operation Overlord) would have been impossible without the LSTs. The German strategy behind the Atlantic Wall was to fortify the ports (such as Dieppe) so that they could withstand a heavy assault. And without a port the Allies could not land heavy weapons or the supplies in large quantity needed by a major army. Actually this strategy worked. The Allies were not able to capture a major port in working order. This handicapped Allied operations after the D-Day landings. Allied armored forces began running out of fuel (September 1944). But the only reason that the Allies got as far as they did because the LSTs which became the work horse of the Allied logistical system. LSTs landed supplies and heavy equipment directly on beaches. The supplies were delivered to the front by truck as the French Rail System had been destroyed. Herr the Red Ball Express was vital. Ships like the Landing Ship Tank (LST), better known as Large Slow Targets revolutionized amphibious operations.

Cargo Vessels

The carriers, battleships, and other fighting ships of combatant navies attract the greatest attention in World War II histories. Ironically the most important vessels were the dowdy cargo/merchant vessels including the tankers. The fighting ships had one primary purpose, the hold the sea lanes open for your cargo vessels or close them for the cargo vessels of your enemy. This is what the fundamental struggle in the key World War II naval campaign--the Battle of the Atlantic. It was according to Primeminister Churchill, the struggle that worried him the most. The Allies approach to this struggle was to steadily increase the escort and U-boat killing capacity of their navies. Surprisingly the Pacific, the Japanese built a large submarine fleet, but did not use it for this purpose, but rather most were tied up hunting naval combat vessels and supplying cut off island garrisons. The second Allied effort was to increase construction of merchant vessels. Here the American Liberty Ships proved that ships could be built faster than the U-boats could sink them even before the tide turned in the North Atlantic. The victory of the Allied fleets (American, British, and Canadian) ensured that the output of American factories and farms as well as oilfields not only reached the American fighting man, but also as part of Lend Lease the fighting men of its allies. The first American offensive in the War was fought over Guadalcanal with the purpose of keeping the sea lanes to Australia open. The Japanese gave considerable thought to their World War II Pacific campaigns. One element not considered was the greatly expanded merchant (maru) fleet needed to fight the Pacific War. And unlike the United States, the Japanese did not have the capacity to significantly increase the construction of merchant vessels, especially when the Imperial Navy began to sustain significant losses. Japan had gone to War to secure the critical material of the Southern Resource Zone (SRZ). Not only did the maru fleet prove inadequate for supplying the outposts spread all over the Pacific and carrying the materials from the SRZ back to the Home Islands, but by mid-1944, American submariners assisted by Ultra had virtually destroyed the maru fleet. Besides escorting or attacking cargo vessels, the only other important naval function was launching amphibious invasions, but even this required the cargo vessels to supply those invasions.


Domagalski, John S. Into the Dark Water: The Story of Three Officers and PT-109 (2014), 264p.

Military History Of the 20th Century


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Created: 8:07 AM 11/26/2011
Last updated: 12:30 AM 4/10/2020