Surprising findings on the physics of water entry could lead to smarter design of ships. The phenomenon of objects entering water is commonplace, yet a full understanding of the physics of water entry remains elusive, especially as it pertains to instances where a solid object enters a body of water that contains other solid objects. A team of researchers has published a series of surprising findings that may lead to strategies for minimizing the strain of water entry on marine vessels, seaplanes, and space-crew capsules designed for water landing. Source 7h.
I'm not sure what efficiencies can be gained for ships and such by understanding what occurs when entering water, as opposed to actually travelling through the medium. That initial entry consumes relatively little energy if compared to time spent while travelling, although impacts and dropped objects for other purposes may benefit. Also, this hydrodynamic study may aid in exploring gas giants and such in space, since gases under pressure have much the same characteristics as fluids.