What an interesting story! There's an Australian description here (click):

Whilst in Hong Kong, Swan (III) utilised the services of Jenny's Side Party, a group of 30 Chinese women ship painters who, without pay, devotedly paint and clean all visiting warships. The Side Party workers supplement their normal operational earnings on non-navy vessels by selling soft drinks to visiting ship's crews.

And photographs here (click) and a British (?) report here (click). I have a brother-in-law who spent his time in the Navy painting his ship while at sea, hanging over the side of the ship in a bosun's chair. I'm sure he would have been grateful for Jenny's Side Party, but I don't see any report of U.S. ships taking advantage of Jenny's services.

I suppose you could consider this folklore, but I'm going to move it to the non-music section.

-Joe-