Boyancy using world position offset

Hi, I am attempting to pass co-ordinate information to a blueprint class to allow it to bob up and down on water. However, after some searching, I have discovered it not being an easy task. I am currently using World Position offset in my material shader to generate my ocean although I looked about, and attempted “toying with” (I don’t do a lot of material work) world displacement. Seen Below

I can’t seem to find any way to get the vector information of any of the vertices. I have attempted the raytracing method but alas, of course, that only returns my mesh’s collision information that is not updated in real-time. I am currently handling all this in blueprint as I have no knowledge of C++

Trivially here is my blueprint setup for the “Shark fin” I am attempting to try and create on the surface

And also the result

If there is an alternate way of doing this I’m all ears but my end goal is to at least get some sort of Z information passed to my sharkfin blueprint.