It's a surfaced-submarine at first,, so I did not make any effort to let it go underwater. Well, it is possible that if you want to go underwater. But I suggest you not doing that. VTOL can work only on surface of the ocean. So you may add another engine. The sub can reach the speed of 300km/h, with torpedos in it.Infacts, I don't really like be hit by the Destroys so the cockpit is in the heart of the sub, and the fuselages are also strong.You can also press"V" avoid being hit by missiles. As I was saving the sub, a problem also came out"What is it name". Then I realized that I had playing computer for a long time and need a rest. So I opened a musicapp. I found the music "Paris" by Else is really good,that's why I named the sub "Paris" As a green hand, i have went my way out to make the sub better,but maybe there are still something bad.Hope you understand! Enjoy!