I have been planning the Swimming Anime Dating Sim since before there was a Swimming Anime! This is a scene from the climax of the game! MWAHAHAHAAHAHAHAHAHAHA!!!!!!
Actually, I was making the game and I went "Crap! I need a teacher!" So I went through my old files for something in the right style. I have another version of this picture that is larger and colored and better quality, so I took the teacher from that. The girl with the knife will also probably show up when I need more characters. I might give her more clothes, but I might not.
Given the clothing choices of most the guys we've met so far in this game, i have the feeling you're going to give this other girl even less clothes...
...And just WHAT is going on here? The climax of this game looks like something from a "Silent Hill" game. Or "Hatoful Boyfriend". Not that there's anything bad about that - it makes it even better, actually.
But, like, really, you're idea looks awesome, and the dateless swimming dating sim is awesome, and most of all - YOU are awesome!