offspling

The I-400 class submarines were designed especially for Seiran, the biggest submarines built up to that time (1945). The Panama strike force consisted of I-401 and I-402 carrying three M6A1s each and I-400 as a fuel tender. There were also two smaller subs carrying two aircraft each. I honestly don't know if they were Seirans or smaller observation/strike aircraft. Unfortunately for the Japanese, the war ended while the strike force was en route to Panama.
I'm not going to post the pics that I have taken of Seiran here that are already on this page
and
this page at j-aircraft.com
That is an AMAZING site if you like Japanese aircraft, it has more than you could ever want to know!