Webster

as far as i know, you cant do it the way it was done in sh3.

for sh4 you can only eliminate some things like floating plankton and blurr effects as well as distortion effects so if thats what you have in mind then:

to remove:

Plankton - open data/ misc folder then delete the "impurity.dds" file

Underwater distortion - open data/ misc folder then delete the "turbulence.dds" file

Plants and rocks - open data/ library and delete the "undersea.dat" and "vegetation_kit.dat" files