Virtual Sailor is a naval emulator to run the seas in different vessels including a submarine.
You will find different options that adjust the weather condition and even the amount of water and aerial animals that are around you.
This will help you create a real background, as each factor directly influence over the surfing, that is, it is not the same a sunny day or a stormy day.
As a good emulator, it will offer the necessary elements so as not to get lost in the ocean, such as a compass and an advanced system of global positioning (GPS).
That is, a good emulator to enjoy a nice marine way, getting real topographic data that respects the environment conditions.