Quote of the Day
Those that travel the high road of humility in Washington are not bothered by heavy traffic.
— Sen. Alan Simpson
I recently purchased the book Collect, Combine and Transform Data Using Power Query in Excel and Power BI by Gil Raviv and am learning a lot – so much so that I am motivated to go hunt some additional data examples for processing by Power Query.
One WW2 topic that continues to intrigue me was how US war planners kept the Imperial Japanese Navy (IJN) at bay long enough to build a large naval force. The key was the use of submarines for commerce raiding to disrupt the war material supply chain and tie down Japanese surface forces with convoy defense duty. This post will use Power Query to scrape the Wikipedia for this data. The Wikipedia is becoming a wonderful source for WW2 information.
Early in the Pacific War, the US Navy could only project power into Japanese waters on a sustained basis by using its submarines. The early actions were often conducted by smaller boats (for example, S-boats) that were inadequate for a theater as large as the Pacific. To paraphrase Donald Rumsfeld, you go to war with the Navy you have – not the Navy you might wish you have. Fortunately, the US had begun building its larger and more capable fleet submarines just before WW2. Figure 2 shows the three classes of fleet submarines that were commissioned during WW2: Gato, Balao, and Tench (in order of introduction).
The Wikipedia maintains a list of US WW2 submarines. I will use this list of submarines to access data from the Wikipedia page for the individual boats. I will filter the data to focu only on fleet submarines commissioned during the war. Some folks may disagree with individual boats on the Wikipedia list. For example, the Wikipedia does not list the USS Mero as a US WW2 submarine, but it technically was commissioned during WW2 so late in the war that it never entered combat. However, their approach is defensible and does not have a significant effect on my results.
I will access the information using the same approach as in this earlier post:
- create a list of WW2 submarine web pages
- access each page and extract the relevant information
- generate pivot tables for the required reports
I followed this procedure to generate a list of submarines commissioned during the war, their shipyard, and the time between keels being laid and submarines being commissioned, which I call the build time. Figure 3 when keels were laid and when boats were commissioned. Note how the number of keels laid dropped precipitously after August 1944. By that point, the IJN was on the ropes and US Navy surface units were in Japanese waters. The war planners saw that more submarines were not needed at that point.
Figure 4 shows the median build times by class. When you consider that the US role in WW2 lasted 44 months, build times of 9 to 12 months were significant, especially when given that it takes additional months for a commissioned boat to get into combat.
Submarines are very difficult to build and the shipyards must have specialized skills, like for the welding of thick steel pressure hulls. There were five shipyards that commissioned fleet boats during WW2 (Figure 5). The Manitowoc yard is on Lake Michigan and had been building ferries and ore haulers prior to the war. While Manitowoc had no submarine building experience, it was able to develop these skills under war-time conditions. I find this an impressive accomplishment. Manitowoc-built subs performed well during the war; one, USS Rasher, had the third-highest sunk tonnage total.
If you are interested in how the data was gathered and analyzed, my spreadsheet is here.