You can remove the so-called 1.1 patch by un-installing the entire SS08, and then re-installing just Ship Simulator 2008. However, you would lose the many bug fixes and added features.
But, if your sole purpose in buying the sim is to see big, unrealistic, waves…
The purpose of the 1.1 upgrade (the word “patch†is a misnomer) was not simply to deprive you of big waves.
Also, remember that VSTEP does not officially support increasing the maximum wave height; you cannot expect technical help on any problems that might be caused by doing so.
Marty