There are some new polymer coatings being put on boats to make them faster. They were developed under navy contract originally for use on hulls. The idea of the coating is to change the surface to being slightly hydrophillic instead of hydrophobic. This has shown to slip through the water better. There was also research done years ago on soft compliant underwater torpedos that were an attempt to replicate a dolphin's skin and their power to speed ratio. What became of this research I can't say. I worked at the company that did research and we had the torpedos and a 60 foot tank sitting around until we scrapped it all. They looked something like a torpedo coated in gel like the sorbothane in bike gloves only much softer. The gel was molded on though and not a spreadable kind of stuff.