Now that I've looked at the camo website a little closer, it looks like a lot of the Balao boats were painted in the MS/9 scheme out of the boat yard, too. Even as late as 1944 USS Becuna (SS-319) had the MS/9. Their new paint jobs being later in the war (1944) matches up with your idea that earlier boats had refit priority, which made sense. They needed more attention due to use and age - especially with equipment upgrades.
|