The holds for the Clyde Cargo steamer appear to be missing from the Github (and therefore, I infer, the SVN) repository for the project, which probably means that they are missing from the pakset as compiled, too: this rather makes the Clyde cargo steamer useless.
Bug continues: The dat files have been present for some time, yet the hull is available 1870/01−1912/01 although the holds are 1853/01−1880/01, so the useful life is only 1870−1879.
ships/clyde-cargo-steamer.dat:
name=ClydeCargoSteamerHull
...
intro_year=1870
intro_month=1
retire_year=1912
retire_month=1
boats/holds/clyde-cargo-steamer-holds.dat — one for example, remainder similar:
name=ClydeCargoSteamerAddMail
...
intro_year=1853
intro_month=1
retire_year=1880
retire_month=1