As I have used Japanese sites only when checking specific ships, I'm not the best informant on what's available, but my investigations have not led me to anything nearly as comprehensive as shipspotting. Actually, having read your question, I trawled a bit and came across many historic photographs, but not in any vast collection. The best pages I found today were in a university archive and have historical photos of liners that used to visit Yokohama. Try pasting and googlinghttp://www.marine.osakafu-u.ac.jp/osakafu-content/uploads/sites/367/5.志澤様.pdf
To translate Japanese text to English, you can just google "Japanese to English" and paste text in. Translation has improved hugely in recent years since they switched from a statistical to a more neural approach (Not my field but I was told this recently by a translation expert).
Incidentally Yokohama port is an interesting place to go --- which I did in Nov. for the first time --- as you can visit the training ship Nippon Maru and NYK's Hikawa Maru, both built in 1930, and NYK also has a museum in the vicinity.