1 hour from Shanghai city to port of LuChao by bus or taxi then 3 hours (55km) from that port to port of ShengSi island by ship. From this port, you can get the north or south beach by taxi and it takes about 15 minuetes.
Seems that this place must be quite potential surf spot around Shanghai area when thyphoon season.Howener, when strong swell and wind is coming to this area, ship may be cancelled. They have many accommdations, so it's easy to find to stay. The color of ocean is close to brown.