Submarines
A submarine (sub) is a watercraft capable of independent operation underwater. It differs from a submersible, which has more limited underwater capability. It is also sometimes used historically or colloquially to refer to remotely operated vehicles and robots, as well as medium-sized or smaller vessels, such as the midget submarine and the wet sub. Submarines are referred to as "boats" rather than "ships" irrespective of their size.
The Guide To Submarines
https://engineers-channel.blogspot.com/p/the-guide-to-submarines.html
Submarines
https://engineers-channel.blogspot.com/p/submarines.html
The Guide To Submarines
https://engineers-channel.blogspot.com/p/the-guide-to-submarines.html
Submarines
https://engineers-channel.blogspot.com/p/submarines.html