Puzzeled on US submarine enemy kills/credit system

[LAstry2]

During the ccourse of US submariens battles in the pacific they obliged to sink enemy ships not just warships but also smaller craft such as sanpans and fishing trawlers....now while such "credits" would be listed in the offical ships history they would not be officaly credited if the sunken/damaged vessel was under 100 tons.....who made up this bizarre rule?

[Delta Tank]

I really don’t know the answers, but maybe you should start here.

https://en.wikipedia.org/wiki/United_St ... ing_Survey

Mike

[Takao]

During the ccourse of US submariens battles in the pacific they obliged to sink enemy ships not just warships but also smaller craft such as sanpans and fishing trawlers....now while such "credits" would be listed in the offical ships history they would not be officaly credited if the sunken/damaged vessel was under 100 tons.....who made up this bizarre rule?

It was only after the war was over that "official" accreditation was done, and tonnage totals for submarines was readjusted up or down from their wartime tallies.

This was the work of the Joint Army Navy Assement Committee.
(JANAC). The report is readily available online.

Further, it was 500 tons or more...Not 100 tons. This was done, because losses of smaller ships were much harder to confirm via wartime records. While, larger 500 ton vessels tended to be more dutifully recorded.

[Takao]

Probably the best work on the subject was a private venture, which was continually updated until the author's passing.
https://books.google.com/books/about/Un ... GNAgAAQBAJ

[OpanaPointer]

https://www.ibiblio.org/hyperwar/Japan/ ... AC-Losses/

[LAstry2]

Thanks for corection