| A | B |
|---|
| SUBMERSIBLE | underwater vessel |
| COMBUSTION ENGINE | used to power subs - used when sub is near the surface |
| PROPELLER | allow sub to move through the water |
| HYDROPLANE | allow subs to be steered |
| BALLAST TANK | system of hollow spaces that allows sub to dive and surface |
| PERISCOPE | tube that can be raised from the sub to the surface so those aboard can see what's going on |
| SUBMARINE | vehicle designed to function deep below the ocean's surface |
| TURTLE | first successful military submarine |
