• my PR #33 fixed landed underwater case, but spoiled case, when a kerbal or a vessel landed on an another vessel, which it splashed on the surface of the water.
• possible adopt future ksp1.7 algorithm
• possible adopt Basic Orbits algorithm, it determines other vessels
• possible adopt SirDiazo's algorithm (the distance from the lowest point on a vessel to the surface):
  https://github.com/SirDiazo/LandingHeight

I am not sure what I was talking about there.