While submerged, submarines can travel faster than when they are on the surface. As water is more viscous and dense than air, causing more friction, how can it travel faster while travelling through a denser medium.
In: 11
Its moving through water either way, the question is what drag dominates.
For surface ships you want a long and skinny hull so it cuts through the water at the front without creating a massive bow wave. The energy that [goes into making this wave](https://en.wikipedia.org/wiki/Wave-making_resistance) is actually the main source of drag for ships.
When fully submerged you need a smooth streamlined shape to let water flow over the surface because you’re not making waves anymore(fully submerged) and only care about skin drag which is the water flowing over the skin of the vehicle
Unfortunate you can’t really get both at the same time. WW2 era subs were optimized for surface operation and moved significantly faster when surfaced because they didn’t have the big bulbous nose of modern submarines which spend almost their entire time under water.
Latest Answers