The anchor sound for shipyards is much louder than other sounds, especially the unanchor sound.  There have been complaints about this for years, but the sound is still the same.  I have finally found a way to "fix" this.

I found a file that defines what sounds to use for some of the sounds.  The anchor sound is in the file.  There are other sounds listed for other situations, so I experimented with different sounds until I found one that is quieter and seems like a reasonable sound for anchoring a shipyard.

I made a mod that changes the sound to the quieter one.  I don't know if it works in existing games or not.  It's worth trying if you have a game going.  It works in new games.  I use it all the time.

You can get the mod here.