Tours run daily and every evening on two large river ferries. The boats, one of which is painted up like a dragon, sail up to Yangpu Bridge in the north of the city, then turn around and chug back down to Nanpu Bridge in the south. The whole trip takes about 50 minutes in the daytime and costs 100rmb, or there are longer cruises at night which include dinner that go for 150rmb. The timing and options seem to change according to the day and the whims of those involved, so it's best to head to this office and speak to those running the show.