# Quality of ships



## Thorlifter (Dec 17, 2016)

It is my VERY uneducated opinion that the US built their ships with good construction standards. Is there anything we built poorly?

What about the IJN? Yes the Yamato and Musashi had the biggest guns of the war. But were they built with high standards? What about the aircraft carriers. It seems several of them were converted from existing ships or converted mid construction. There was even a 3rd Yamato battleship (the Shinano) being built that was converted to a carrier. Does a converted ship lead to poor construction?

What about the Kreigsmarine and the Italian navies? It is my understanding the cruisers and pocket battleships were very well built. What about the rest of the navy?


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## Capt. Vick (Dec 17, 2016)

I remember when Dr. Bob Balard found the Bismarck, there was talk of a design flaw that allowed the stern to break off. It was said that it was pretty universal among the pocket battleships.


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## Glider (Dec 17, 2016)

No country is perfect including the USN which was pretty damn good. If there was one complaint about the USN it was that the ships tended to be top heavy.
Its fair to say that all warships added weight as the war progressed but the USN had a particular problem made worse by the huge increase in AA guns that were needed. The impact could be significant.

Other navies had much bigger problems and I am not trying to run the USN down, just recognising that it wasn't without some problems


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## Thorlifter (Dec 17, 2016)

Thanks Vick and Glider. I agree Glider. I wasn't trying to say the USN was perfect. I'm sure there are flaws and failures in designs and construction with all branches of all nations.


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## Glider (Dec 18, 2016)

To take the navies mentioned.
Italian 
There were factors that influenced the design of the ships which with hindsight were counter productive. Like the French navy there were significant bonuses if a ship exceeded its design speed. As a result the ships and in particular the light cruisers tended to be lightly built and fragile in combat. That said the majority of the fleet could be described as very effective combat ships which were once described to me as being good average vessels and in wartime that is what you need, a good average.
The biggest problem the Italian Navy had was the lack of technology. Radar, Sonar, communications were always difficult and without them the ships became sitting ducks. Cape Matapan was a classic example. Without Radar the Italian cruisers were little more than target practice. If they had effective radar, then those fast cruisers well armed with effective torpedos would have been a very serious risk to the British battleships. 
Some designs were almost inspired. There was a submarine armed with 17.7in torpedos specially designed for anti convoy work. The logic being that for the normal merchant ship and escort that was all that was needed. The benefit being thatyou could carry a lot more torpedos and torpedo tubes. One corvette class had a secondary electric drive so it could also do the equivalent of silent running.
German
I think the biggest problem was an almost fetish for over complicated engine rooms. A lot of their ships had very high pressure boiler systems which had major reliability issues. The Pocket Battleships had diesel engines which also hd a lot of major reliability problems around the bearings. 
Both navies had poor leadership. No one should question the bravery of the crews but the Admirals were very poor.


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## Capt. Vick (Dec 18, 2016)

I also heard that the first liberty ships had a fatal design flaw in which they might literally crack in half in rough seas. The problem was corrected later in the war by welding on doubler plates.


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## DerAdlerIstGelandet (Dec 18, 2016)

Thorlifter said:


> Thanks Vick and Glider. I agree Glider. I wasn't trying to say the USN was perfect. I'm sure there are flaws and failures in designs and construction with all branches of all nations.



Absolutely correct. Libert Cargo Ships and Tankers as well.

The SS Pendleton (the story recently told in the movie Their Finest Hour), broke in two in a storm in the 1950's because of this problem. The ship was a T2 Tanker.

SS Pendleton - Wikipedia

T2 tanker - Wikipedia


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## vikingBerserker (Dec 19, 2016)

IIRC the problem was made worse when it was really cold.


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## pinehilljoe (Dec 30, 2016)

I think the quality of construction and design was as good as any other country. All ships are a trade of firepower, speed and protection. The US had a philosophy that seemed to work. Many of the Pre War and Early War designs were top heavy by '45. The Cleaveland's were probably the most top heavy. The extra AA, radar, crews to man them drove them to being top heavy. All the ships had AA added during the war. Some destroyers landed banks of torpedoes to keep the weight down. The Brooklyn's were bulged to help with the top weight as they went in for refit in the second half of the war. The late war designs like the Worcesters, Newport News CA's solved this.

The fact that so many ships lasted long after the war speaks to the quality of the machinery and design. Lexington was the last CV from the Essex class and served until 1991 as a training carrier. The Iowa's kept going (though on and off) to the early 90's. Poor quality machinery wouldn't have lasted 50 years. Scores of Fletcher's and Gearing's served into the 80's in other Navies. Not to say other country's machinery wasn't good quality, but the US being the winner, had a lot of ships after the War and were able to demonstrate the test of time. The RN War era carriers lasted long in foreign service, the two Indian carriers going into the 2010's, albeit, Vikrant was re-boilered. The Prinz Eugen had a reputation for having problematic machinery. She had to be eventually towed to Bikini Atoll.

Damage control was excellent on US ships, I think arguably the best in the world, whether by design, construction, or training. The fact is Japanese ships suffering damage like the Enterprise, Bunker Hill, and Franklin, simply didn't survive. This is true early and late war. The Yorktown's and Essex's proved hard to sink. Yorktown could have been saved if the submarine didn't find her.

Also what set the US ships apart from the Japanese was the availability of Radar Fire Control technology.

The Liberty ships suffered from the new technology of an welded ship design. The science of stress risers and welds was in its infancy. A weld crack would start and race around the ship in seconds breaking the ship in two. Some ships would fail right after launching. Later Liberty ships used better technology of weld stops, minimal sharp corners, and the weld losses were less.

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## Wavelength (Feb 5, 2017)

Electric arc welding as it is known today came of age during WWII. The US and Germany employed extensive welding in warship construction. Nobody else, if we don’t count HMS Vanguard, did until post WWII. I was told once that 18,000 welding rods were used in the construction of the Yamato, but that is nothing for project of that magnitude. Riveting was still the most common joining technique for naval construction outside of Germany and the United States. Even in German ship yards the Kriegsmarine still prohibited welding directly to armour bulkheads at the time that the Bismarck was constructed. If they had allowed welding to the aft transverse armoured bulkhead, then the distal end would not have detached after the battleship sank. The USN may have employed welding more extensively than the Germans, although the Germans were the first to commit to at least 90% welded construction with the panzershiffs. (incidentally the stern collapses after being struck by torpedoes on the panzershiffs involved a riveted joint, not a welded one.)


There are several advantages to adopting welded construction. One of the most important is that it weighs less. With Deutschland the savings was 15% less weight in the hull alone. This allows more ship to be squeezed into less tonnage. It allows more tonnage to be committed to armour, or firepower, or propulsion, or range. And it was one way of cheating the intent of displacement limitation treaties.


The strength of a riveted joint is the tensile strength of the rivets. A welded joint may have a weld metal that matches the strength of the parent metal, or that exceeds the strength of the parent metal or that is less than the parent metal. The advantage of undermatching is that the welded joint will be less brittle than if it matched or over matched the parent metal. The Liberty ships used mild steel welded by relatively brittle 6010 weld metal.


The Japanese eschewed welding because of early 1930s failures of welded joints on heavy cruisers caught in heavy storms. The Japanese copied the British almost exactly in the use of construction materials. Their construction steel used for warships was Ducol (aka D-steel) exactly the same as used by the British. As did the French. The Japanese also copied the British armour plate metallurgy exactly as well. The French did not. However, Ducol welds poorly. The KGVs were therefore of riveted construction and is believed to have contributed partly to the low of HMS Prince of Wales.


D-steel or Ducol has a fairly high carbon content which creates problems for welding. The relatively high carbon content gave Ducol a high tensile strength of 80,000 psi. During the war the British employed DW (Ducol Weldable) steel in the construction of HMS Vanguard. DW had a reduced carbon content, which reduced the tensile strength to about 75,000 psi.


The USN employed more weldable mild steel or high tensile steel. Mild Steel has a tensile strength of 60,000 psi, and HTS has a tensile strength of 70,000 psi. Top USN warships, such as the new fast battleships, also used special treatment steel or STS as a construction/structural steel. STS is homogenous armour grade steel. Only the US could afford such extravagance. 


STS is weldable. Stainless steel is used to weld armour plate. A weld metal with 25% chrome and nickel (today known as 310) was used to weld STS. A 20% Chrome and nickel content welding rod (today known as 309) was used to join STS to either HTS or MS. 309 may have been used to join MS and HTS as well. Stainless steel is by default a low hydrogen welding material, so that provided an automatic avoidance of hydrogen embrittlement, that caused most weld failures on early welded ships. Stainless steel under matches (but over matches mild steel and high tensile steels) armour grade steel, but it is very ductile and avoids embrittling the weld zone.


The Germans had the most advanced metallurgy used for welded warship construction of that time period. The construction steel ST-52, as well as the Wotan homogenous armour types, were designed to have very good weldability. Indeed, ST-52 became the standard ship building material worldwide following WWII, and it still is today. The welding electrode developed for ST-52 was known as the E52 and was a low hydrogen type. The German stainless steel welding rod for homogenous armour was the Fox A-7, known today as type 307. 


The Italians also welded armour materials but their technique of grinding the weld repeatedly as they went, to check for cracks, depleted the weld metal of vital alloying agents

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## ChrisMcD (Feb 16, 2017)

Not my subject, but I thought American face hardened armour plate was not considered to be the best?

American battleship armor overrated? - Naval History Forums


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## Wavelength (Feb 19, 2017)

Yes, that is correct. US face hardened armor is considered among the worst quality of ww2. It is considered about 25% less effective against large caliber ordinance than British CA (cemented armour). British CA is considered the standard of face hardened armor quality. So, that 12-inch belt on an Iowa class battleship is only really worth about 10-inches of British CA. The German face hardened armor KCnA (Krupp’s cemented nue art) was within the margin of error of the British CA quality, and Italian Terni plates may have exceeded the British standard slightly.


Much of the problem for the American armor manufacture was America’s commitment to the terms of the Washington Treaty. The treaty not only placed a moratorium on new battleship construction, but also suspended the R&D of guns, armor, and armor piercing shell, technology. When the USN Bureau of Ordinance resumed research around 1935, they scrambled to catch up, and the US steel manufacturers sent engineers to Krupp’s in Germany to find out the state of the art of armor plate manufacture.


Why to Germany? The Germans had continued R&D in such technologies all along, despite the terms of the Versailles Treaty, clandestinely. They were able to do this because German naval technology was centered in private industry rather than through state controlled agencies. The Germans were well ahead of the curve, while their potential rivals were still stuck in 1925 era thinking. 


However, American industry was not able to duplicate Krupp technology because the infrastructure of American steel manufacture was obsolete, partly the result of the R&D suspension, but also because of the Great Depression shutting down industry and preventing investment in new infrastructure. The Germans, specifically Krupp, already used brand new electric arc furnace steel smelting, and heat treatment technologies. This allowed manufacture of state of the art plates of significantly higher quality with significantly less impurities.


Among the specific problems with US face hardened plates was the depth into the plate that the face-hardened surface extended into the plate. With British CA the face-hardened portion only extended to about 25-30% into the thickness of the plates. The Germans tried for 33%. The American plates ended up more than 45%. There were also problems with cracking and delamination’s.


Bureau of Ordinance knew about these quality problems, and there were even secret congressional hearings conducted investigating these problems during the war. One attempted amelioration of the poor quality of face hardened plates, was to substitute homogeneous plates for face hardened plates. However, the thickness of rolled homogeneous armor should not exceed about 15cm thickness in order to retain high quality. When homogeneous plates of over 40cm were used, the quality was still about 15% substandard.


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