Liberty Ships

One of Roamy’s very first posts here concerned the WWII emergency shipbuilding program known as Liberty Ships.

As it happens, I recently acquired a book on Liberty Ships.

The haste with which they were built, and the relatively new technology of welded hulls, lead to some issues with brittle metal, and hull failures, especially in cold water.

The massive Liberty Ship program was designed to quickly build as many general purpose (break bulk) cargo ships as possible. The Liberty Ships were simple, but not crude.

The primary bottlenecks in shipbuilding were these:

First, the program could not be allowed to compete with existing merchant and warship building. To avoid this, entirely new yards and slipways were built (at government expense). In fact, many of the companies that operated these yards had no history of shipbuilding at all. Indeed, these neophyte firms often brought innovations to shipbuilding that left older firms aghast, but were eventually adopted by traditional firms, and are still in use today.

Second, the real bottleneck in production was propulsion. By 1940, the triple expansion steam engine was widely considered obsolete in American merchant marine service. But most production intense part of a steam turbine plant is the reduction gearing. There was a very real limit to how much gear cutting capacity America had or could be expected to achieve, and virtually all that was allocated to warship production. And since geared turbines were out, the old triple expansion steam engine was pressed into service for the Liberties. That actually meant that a school for teaching how to maintain the older technology had to be opened. The relative simplicity of the TESE meant that foundries that normally had no maritime connection could also be used to build engines.  The boilers were also relatively simple (though not crude) and could similarly be build without competing for the limited capacity of traditional boilermakers for warships.


Now, you know that massive losses to merchant shipping to U-Boats in the Atlantic spurred the Liberty Ship program.

What surprised me was the relatively small numbers of Liberty Ships that were lost to U-Boat attacks.  I suspect it is because the worst losses of the Battle of the Atlantic took place before the Liberty Ship program really started placing large numbers of ships into service. That is, most were replacements for losses already incurred. There were appalling numbers of losses, but most were from mechanical casualties, and very often after 20 years of service.


One thing I found rather spartan about the ships was that the navigation suite consisted primarily of a magnetic compass. Combined with a sextant and charts, that was about it. The lack of a gyrocompass was surprising. Virtually none of the Liberty Ships was fitted with radar of any sort during the war.

2 thoughts on “Liberty Ships”

  1. My favorite Liberty is the ARMADILLO Class Liberty Tanker USS GIRAFFE. Is there any mention of the Liberty Tankers? What is the name of the book, so I can get one?

    1. I know the book mentions them, and even has a picture, but it doesn’t go into any detail. It’s mostly a list of the production of each yard, and the fate of each ship. It doesn’t get into a lot of detail on the specifics of each design.

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