To understand why Shaolin Kung Fu will never be a submarine you must understand what a submarine is. A submarine is a shape designed to travel through a specific liquid substance. Because of this all submarines eventually come to be the same shape.
This is just the physics of the matter. The submarine is designed conical because that is the best shape for traveling at speed through water. Any other shape would cause the submarine to slow down, or travel inefficiently.
If the sub travels slower, it can be shot by enemy subs. If it has a different shape it cannot turn quickly enough to defend itself. This is all related to combat and combat functions.
Shaolin Kung Fu is taught by patterns, and the patterns are designed to travel through a different substance. The Shaolin forms are designed to travel through air, and with an eye to the effects of gravity. But such considerations do not limit the Shaolin master, but rather unlimit him.
The patterns, you see, are designed around the construction of the body, and the body can react to air and gravity in many different ways. The body of the Shaolin Master is trained to act other than a human body. The body of the Shaolin Master can take on the aspects of a Monkey, or a Crane, or any other animal.
Thus, the limit of the environment is changed by the body that is traveling through it. And the body traveling through it is changed by the considerations of the being operating the body. And, the person operating the body can change how he uses it on a whim.
A submarine can never change, and if you built a submarine in a different shape, the submarine would not work. But Shaolin monks are built to assume a variety of shapes. The key is the mind.
The ability to change shape, to shift the way one moves, is possible through enhanced intelligence. To learn how to use the body in a variety of ways enhances the intelligence. It may have taken great intelligence to make a submarine, but a submarine can’t do Shaolin kung fu, and will never be a Shaolin Kung Fu Master.