Sometimes, the most absurd idea can yield some fascinating results. The latest to fall into the category is Eastman’s Hunting Journal who took to experimenting with archery underwater.
At first, I thought it was going to be a miserable failure (especially considering bullet’s tendency to lose velocity in mere feet), but seeing the release, of the arrow continues towards its target with lethal velocity for significantly longer than a bullet.
Its basically a long flachette and its shape and relative lack of velocity allows it to move through the water without losing energy as quickly. For those looking for the scientific reasoning, turn to Andy Lemke, a physicist on Quora answering, “How much speed does a bullet lose when fired into water?”
It depends on how long is has been in the water, what the speed was when it entered, the drag coefficient for the bullet and the density of the fluid. The initial speed is entirely variable here. Are we talking about a little 9mm or a .50 cal round?
I can tell you however, the relationship between drag force, velocity and the density of the fluid. Drag force scales with the square of velocity andwith the density of the fluid:
Now ρ for water is about 1000 greater than it is for air. This means that the drag force will immediately increase by a factor of 1000 once a bullet hits the water. From that point on, the velocity will rapidly attenuate with every millimeter traveled, but you probably already knew that.