Searching web databases and extracting data

I need to lookup certain ships in http://www.veristar.com/portal/veristarinfo/generalinfo/registers/seaGoingShips registry of ships and extract certain data from the database. I can access the data by HTML but I do not know how to conduct the search. Vie HTML I can change the value of the input, but unaware how to press search. The URL is generated randomly. Thank you