This was a pretty good animation. Good music. It was really short though. I get what you were going for, but there was very little actual content. You probably could have done an animated gif and gotten the same effect. That and having no actual sound effects sorta took away from the movie as well. Overall, it was pretty good though, aside from the lack of sound sorta making the animation a bit bland. Other than that, the animation itself deserved a good mark.
That said, I don't think a scene like this has any place in the RWBY series anymore. Maybe in the Chibi series. Any anime that does the whole beach thing is just fanservice, and RWBY saves all that fanservice crap for the Chibi series cause that's pretty much all that series is. I personally think the RWBY series needs to end. It's completely derailed after Monty Oum died and it's just spiraling downhill in terms of story. The only way you'll probably get one of these scenes is to make it yourself, which it sounds like you already started here.