If by RS you mean Remote Sensing, I guess your focus should be aerial bathymetry. I understand that the very science of Hydrography is remote sensing as you don't need to contact the seabed to learn about it.
But aerial bathymetry is sort of the first thought that comes to mind when I heard RS and bathymetry - for obvious reasons.
What you need is a LiDAR sensor, UAV (preferably) and the LiDAR sensor processing software; this will help you handle the point cloud data and prepare your data for post processing.