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A lot of Liberty Ships were built during WW2. These were fairly large transport ships with a capacity of about 11,000 t deadweight tonnage. Wikipedia says the average build time was 42 days, and that the workforce was newly trained because no one had ever made welded ships before.

I would like to know how big was the workforce that constructed them? In other words, how many people worked on one in the drydock? And were they divided into 3 shifts for round-the-clock work?

I'm just interested in the ship construction. No need to factor in things like engine building at a factory somewhere else.

Edit: Actually, I want the work to build/assemble the ship, both on the slipway and on the water. Before posting this question, I did not know that ships were finished on the water. (I heard of "fitting out" before, but thought that was only stuff like bringing in food and beds and misc. stuff like radios and other small equipment.)

  • So just the work to build the hull prior to launch (typically about 1/2 way through total construction)? – Pieter Geerkens Jul 4 '18 at 21:55
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    @PieterGeerkens To build the hull and insert whatever is needed before launching. I imagine construction around the engine plus inserting a lot of tubes and wires. In other words, constructing the hull and assembling it with anything else (stuff that is not "fitted out" after launch). – DrZ214 Jul 4 '18 at 22:08
  • @PieterGeerkens On second thought, no. I want the work to build/assemble the ship, both on the slipway and on the water. I will edit OP. – DrZ214 Jul 4 '18 at 23:51
  • Are you asking for the number of full-time-equivalents, or the actual number of individual people? To achieve high production rates, people were specialized. Some would spend lots of time on one ship, some would spend some time on a number of ships. – Jon Custer Jul 5 '18 at 13:43
  • @JonCuster Ideally, the best measure is how many labor-hours went into the construction/assembly of one ship. I think my answer achieved that simply from the peak labor force divided by the number of slipways. That should factor in the specialized labor rotating around all the ships, plus the normal labor ofc. – DrZ214 Jul 5 '18 at 18:56
14

Looking at one specific ship yard, the North Carolina Shipbuilding Company:

Nine shipways were constructed, producing 126 Liberty's and 117 larger ships between Dec. 6, 1941 and the end of the war. Peak employment in 1943 was 21,000 employees in three shifts.

Historically, it was typical for a ship to be launched about 1/2 way through construction. If we use that as an estimating factor, then there would be nine each of launched and unlaunched vessels under construction at a time. This would suggest a shift in each dry-dock of about 21,000 / 3 / 18 = ~390 workers.

(As a publicity stunt) the SS Robert E. Peary was launched 4 days and 15 1/2 hours after laying-down of its keel, with outfitting complete ten days after that, by Permanente Metals Corporation (Kaiser) No.2 Yard in Richmond, California

Excerpt from deleted comment:

I doubt shift sizes varied much between ship types - time in drydock by the same team more likely in my opinion. Besides - this would have varied over the course of the war as well. I doubt an estimate closer than 20% is possible without actual timecard records.


P.S.
Shipway - The sloping drydock in which a ship is built and from where it is launched. Not to be confused with a slipway, which is subtly different in important ways.

It's not a Liberty Ship, but here is footage of Titanic's launching in 1911 from its shipway. Note how little of its superstructure has been completed at this point. Comments to the video claim that it is actually of the Olympic, one of Titanic's sister ships, because of the white hull. However here is a picture of the two side-by-side not long after, both with black hulls. This leads me to believe that the white hull in the video has only been primed, on preparation for final painting after launch. A more experienced eye than mine might be able to make a definitive identification from superstructure differences between the two ships.

  • it was typical for a ship to be launched about 1/2 way through construction Never knew that before. Do they just build the bottom half so it will float, then complete the top half out on the water? Sounds kinda dangerous imo. What if it rains and fills the bottom half with water? – DrZ214 Jul 4 '18 at 22:13
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    @DrZ214 Dry-docks are very expensive, and construction time in one correspondingly expensive The faster you can get hulls out of the dry-dock, the less expensive the ship is to build.. Think of building a house there remains a lot of work to be done on the house once the walls and roof are up. It is a rule-of-thumb not a hard guideline. – Pieter Geerkens Jul 4 '18 at 22:21
  • The 117 larger ships will bias the estimate, especially depending on how much bigger they were. Do you have a source for that BTW? It has no source in the wiki article, and the external links have 2 out of 3 dead links. The list of ships on the page itself, at rough glance, all seem to be about the same size as a liberty ship (in terms of displacement), but is only about 55 ships. – DrZ214 Jul 4 '18 at 22:34
  • I'm sorry, but what is Revolvy.com doing as a source? It even says near the bottom, "content from wikipedia". It's just copying wiki text and putting it in an ad-infested website. I think you should delete it. About ship sizes and shift sizes, I'm not suggesting shift sizes varied much, I'm saying there are 9 shipyards and we don't know how many were building "larger ships" vs how many were building liberty ships. 21,000 total workcrew, but statistically, it is very dangerous to take the average like that. And varying over the course of the war is another huge reason to not rely on averages. – DrZ214 Jul 4 '18 at 23:01
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    @DrZ214 the ship is launched when the hull is water tight, usually including putting the major substructure on. After that comes the longer process of fitting out, putting in cabins, mess, bridge equipment, cabling, piping, everything that makes a floating metal box a ship (though the engines are usually installed in dry dock before the hull is closed, then later connected and tuned while afloat). – jwenting Jul 5 '18 at 11:33
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This website apparently gives a comprehensive list of all the ships built at The Bethlehem Fairfield Shipyard in Baltimore Maryland between 1941 and 1945. It even says which slipway built which ship (but some entries on that are empty), how long it took, and how many days it was on the slipway vs how many days on water. It also has a column called "MC#" which I'm not sure about.

It also says:

Its 13 ways were increased to 16 in the second wave of shipbuilding expansion and at its peak the yard had 27,000 employees

I looked in the chart, and slipway # 16 appears as early as 1941 June.

Sadly, it does not say when the peak employment occurred, but I will go out on a limb and guess it's 1943. I say that just because, to the best of my memory, a lot of WW2 stuff from USA peaked in 1943. If anyone can correct this or find out definitively when the Bethlehem Yard had peak employment, please let me know.

Anyway, according to the table, for the entire year of 1943, nothing but liberty ships were built at all 16 slipways. So trusting Wikipedia's statement that the average build time was 42 days, and 16 slipways with 27,000 workers, this comes out to about 1,700 workers per ship.

Note: For some reason, the table becomes anachronistic when it jumps to "LST" in the middle of the table. You can see the keel laid dates jump from summer 1943 to summer 1942. No clue why it does this, but it does make me worry that the list is not truly comprehensive. You can see the Slipway # missing from that data too.

  • OK, just remember that Bethlehem Steel had at least 3 different shipyards in Baltimore at the time. I don't kniw if the 16 total is just for Fairfield or all of them. – Spencer Jul 5 '18 at 12:58
  • @Spencer Do you know the names of the other Bethlehem Shipyards in Baltimore? Hopefully I can find similar lists for them, once I know the names. Wikipedia has a list of Bethlehem Shipyards, but only mentioned 1 other in Maryland (Sparrows Point, not sure how close that is to Baltimore): en.wikipedia.org/wiki/Bethlehem_Shipbuilding_Corporation – DrZ214 Jul 5 '18 at 18:16
  • There was one at Sparrows Point, just outside the city proper, and which apparently made tankers during WWII, and another at Key Highway, which may have been mostly involved in repairs. – Spencer Jul 5 '18 at 22:13

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