as you probably know the japanese didn't have a real radar on subs during WWII, instead they relied on "ears" to spot approaching airplanes, with the success one knows
I saw in one of my latest (1979) IJN sub book that the Kaidai and the Jyunsen b were fitted with those. I decided to do the same (maybe for a late war tower?)
I also added the horn stuff (isn't that a schnorkel ?)
there it goes :