I was not able to reproduce this same error on several machines I tried (Intel GPU, AMD R4) , but eventually found that a Win10 with a GTX1060 had this same problem. After some internet research, I eventually discovered what the problem might be, tried a fix and it worked for the GTX1060. I also found another person with an AMD Quattro that also had the problem and the fix worked for them too. So the next Maelstrom update will contain this fix for this DX9 AA underwater problem.
For texture conversions:
https://mega.nz/folder/O4lX0QRY#uD7AEuyTgJa5iZRZIHRICg
TextureWrite.zip contains:
TextureWrite.exe
ConvertTXtoTGA.cmd
I wrote TextureWrite.exe and it will convert most of the .tx formats to .tga, if they are uncompressed; it will not convert any of the compressed formats to .tga. If you place the ConvertTXtoTGA.cmd file in a root directory, it will recursively search and convert all the files in that directory and also all the files in subdirectories under that root folder. Be sure to edit the .cmd file to point to the proper filepath location you put the TextureWrite.exe file; it currently assumes C:\TextureWrite.exe.
Also, MK would like to obtain several ships from Secret Beach, including a schooner and a snauw. Is there any chance we could obtain them?