I was doing some research on the Tonan Maru 2 and 3 in order to make a model of it...came across some good sites with models and/or specs of various Japanese merchants and naval auxiliaries. Apologies if these have been posted before.
http://ww6.enjoy.ne.jp/~iwashige/modellist.htm
http://www.combinedfleet.com/Akashi_t.htm
http://www.combinedfleet.com/Kosakukan.htm