It is.
Before doing anything else, install il2 selector, run it and select "change settings", choose "hsfx/classic mod game" in "game type" and save.
https://www.sas1946.com/main/index.php?topic=16403.0Then,
1/use jsgme, easier
2/using the installer, unzip where you want
3/the "il2ge" folder created goes into jsgmemods/the_name_you_like_best (I chose C:\Jeux\HSFX7\jsgmemods\#_____Graphic_extender)
4/activate via jsgme
5/launch game
6/say "wow, water is awful ! what is this il2ge.ini in my main folder ?"
7/make a copy of your conf.ini and il2ge.ini somewhere else.
8/deactivate
9/those conf.ini and il2ge.ini you copied, put them in your jsgme "the_name_you_like_best" folder
10/modify the conf.ini to use water=1, StencilBits=8, DynamicalLights=0 in the openGL subsection
11/search "carmaster water" and install it via jsgme (in the end it looks like this in mine C:\Jeux\HSFX7\jsgmemods\#___________carmaster_water_for_ge\FILES\Maps\_Tex\water )
12/once carmaster water is activated, reactivate "the_name_you_like_best"
13/enjoy (don't play at night tho, yet, and don't look in your rear mirror too often)