First, it's worth pointing out that pre-WWII, shipbuilding was essentially shaped by its origins as a low-capital industry. In the days of wooden shipbuilding, you basically needed a piece of land next to a river or ocean and supplies of labor and timber. The cost of everything else was a rounding error, and it was not uncommon for "yards" to pop up in times of high demand, then go away afterwards. This equilibrium persisted into the days of iron, and while stuff did get more specialized, you still saw stuff like Thames Iron Works getting HMS Thunderer in about 1910, despite not having built anything of remotely similar size before. (Details are in Battleship Builders, which I really should re-read.)
>They developed new, more efficient hull forms, such as the “bulbous bow” which reduced drag from waves.
Two points: first, the early bulbous bow was developed in the US around 1900. (I am pedantic because my ship has one.) Second, it should probably be "wavemaking drag". Ship drag comes from either skin friction or from the wake made as the ship moves through the water. The bulbous bow helps with that. I don't think it has much effect on performance in rough water, but I could be wrong on that.
>I had a hard time figuring out exactly why drydocks are superior to slipways.
A lot of it is the safety issue. There's a book called "The Yard" about the building of a destroyer at Bath Iron Works that covers the mechanics of launching in a fair bit of detail, and is generally a good read. I cover some of this at https://www.navalgazing.net/SYWTBABB-Construction-Part-2. I don't recall the angle of the slip being mentioned as a major problem, although it did come up on the list of reasons they preferred to do work on modules in the factory building. The big issue with drydocks is just that they're a lot more expensive than slipways, and only make sense if you assume consistent long-term production rates.
I would love to learn more about why "Ludwig wanted to build even larger ships, in part to capitalize on the burgeoning iron ore trade with Venezuela." Minnesota's Iron Range benefited greatly before the 1950s from the lack of long-distance international trade in iron ore, giving it a virtual monopoly with US steel makers. I've read vague discussions about improvements in shipping creating an international market in ore but would appreciate learning more, especially from scholarly sources. Thanks!
There's a book called The Shipping Revolution which covers a lot of the development of the modern merchant ship, and which I used as the basis for a series on merchant ships, including https://www.navalgazing.net/Merchant-Ships-Bulk-Carriers on bulk carriers. (The only downside is that it's from the early 90s.) I didn't cover this in detail, and it's been a few years, but I suspect a combination of lowered international trade barriers and a general willingness to rethink things that also saw the rise of the container. Shipbuilding wasn't in great shape between WWI and WWII because of the flood of wartime cargo ships hitting the civilian market followed by the Depression.
I lived in Japan in the 1960s and was friends with a Greek naval engineer who was the local agent for most Greek lines who ordered Japanese ships.
He loved to regale me with tales of Japanese cheating, which were on a scale that matched the ships themselves. In one case, his instinct prompted him to measure the length of an about-to-be delivered ship, which he found to be 4 meters shorter than the specified length! In another case, he found a delivery-ready KHI engine produced suspiciously few turnings/shavings during its running-in. The trick, he found, was that the magnets that were supposed to attract these little fragments had been replaced by non-magnetic replicas.
Footnote #2 is particularly timely, regarding the safety of dry dock vs. slipway. The damage during launch of the North Korean destroyer looks like it might have happened on a slipway.
Ooh, more shipbuilding. OK, I have thoughts.
First, it's worth pointing out that pre-WWII, shipbuilding was essentially shaped by its origins as a low-capital industry. In the days of wooden shipbuilding, you basically needed a piece of land next to a river or ocean and supplies of labor and timber. The cost of everything else was a rounding error, and it was not uncommon for "yards" to pop up in times of high demand, then go away afterwards. This equilibrium persisted into the days of iron, and while stuff did get more specialized, you still saw stuff like Thames Iron Works getting HMS Thunderer in about 1910, despite not having built anything of remotely similar size before. (Details are in Battleship Builders, which I really should re-read.)
>They developed new, more efficient hull forms, such as the “bulbous bow” which reduced drag from waves.
Two points: first, the early bulbous bow was developed in the US around 1900. (I am pedantic because my ship has one.) Second, it should probably be "wavemaking drag". Ship drag comes from either skin friction or from the wake made as the ship moves through the water. The bulbous bow helps with that. I don't think it has much effect on performance in rough water, but I could be wrong on that.
>I had a hard time figuring out exactly why drydocks are superior to slipways.
A lot of it is the safety issue. There's a book called "The Yard" about the building of a destroyer at Bath Iron Works that covers the mechanics of launching in a fair bit of detail, and is generally a good read. I cover some of this at https://www.navalgazing.net/SYWTBABB-Construction-Part-2. I don't recall the angle of the slip being mentioned as a major problem, although it did come up on the list of reasons they preferred to do work on modules in the factory building. The big issue with drydocks is just that they're a lot more expensive than slipways, and only make sense if you assume consistent long-term production rates.
I would love to learn more about why "Ludwig wanted to build even larger ships, in part to capitalize on the burgeoning iron ore trade with Venezuela." Minnesota's Iron Range benefited greatly before the 1950s from the lack of long-distance international trade in iron ore, giving it a virtual monopoly with US steel makers. I've read vague discussions about improvements in shipping creating an international market in ore but would appreciate learning more, especially from scholarly sources. Thanks!
There's a book called The Shipping Revolution which covers a lot of the development of the modern merchant ship, and which I used as the basis for a series on merchant ships, including https://www.navalgazing.net/Merchant-Ships-Bulk-Carriers on bulk carriers. (The only downside is that it's from the early 90s.) I didn't cover this in detail, and it's been a few years, but I suspect a combination of lowered international trade barriers and a general willingness to rethink things that also saw the rise of the container. Shipbuilding wasn't in great shape between WWI and WWII because of the flood of wartime cargo ships hitting the civilian market followed by the Depression.
Thanks, this is very helpful.
I lived in Japan in the 1960s and was friends with a Greek naval engineer who was the local agent for most Greek lines who ordered Japanese ships.
He loved to regale me with tales of Japanese cheating, which were on a scale that matched the ships themselves. In one case, his instinct prompted him to measure the length of an about-to-be delivered ship, which he found to be 4 meters shorter than the specified length! In another case, he found a delivery-ready KHI engine produced suspiciously few turnings/shavings during its running-in. The trick, he found, was that the magnets that were supposed to attract these little fragments had been replaced by non-magnetic replicas.
Footnote #2 is particularly timely, regarding the safety of dry dock vs. slipway. The damage during launch of the North Korean destroyer looks like it might have happened on a slipway.
Any thoughts on the Jones Act as it relates to the subject at hand?
I think the Jones Act is overrated as a driver of US shipbuilding inefficiency https://www.construction-physics.com/p/why-cant-the-us-build-ships