I addressed the nation assignments in an earlier post, but I shall do so again as there is still confusion.
I am not sure which nations had old whale factories converted from liners or freighters, but the UK, Germany, and Norway almost definitely did. Purpose-built whale factories were definitely used by the US, UK, Norway, Germany, and Japan.
I think the following nations may have had some but I am not sure: Sweden, Russia, Australia.
I am pretty sure that the following nations had no whale factories of any kind, although I could be wrong: Canada, New Zealand, Italy, Mexico, Spain, Portugal, any Eastern European nations, or France.
EDIT: - The NCVW should show up in the stock campaign for the UK, US, Greece and Japan. There are many more nations which can use this ship in RUB, but not all of them had whale factories.
BTW - Here is a picture of a purpose-built whale factory, the Kosmos II. Iambecomelife is making one similar to this.
I would post a link to the picture that I based mine upon, but I can't find it anymore.