I did find one of those other "Harbor" thingies has a "smaller" breakwater that might be more appropriate. Of course, though, that is a "modern" image on Google, so there may not have been any breakwater there at all, and the docks may have been 10 miles away from where I put 'em...
I don't know if you've looked into the history around Singapore, but the game has the harbor on the wrong side of the island. There's a few others that are way off also. I'm thinking though that some of the choices were in the interest of game play, since it would take quite a while to get out of Singapore if it was on the other side of the island. That would be similar to Sasebo for an IJN base on the Japanese side...
- or Singapore...
