I and someone else had made a replication of a really ancient submarine. It wasnt even a real submarine, as it had only large wheels to move against the bottom of the sea. The ship was shaped like a red giant anvil, with the large metal hatch on the top of it going over the egg-shaped travelling space. In front of the ship was a mound with a head-sized metal ball in it, and the ball had a long cylinder of glass going through it, making it an eye-like window. The wheels at the rear end of the ship looked like ones in the first tractors ever built, and the front of the ship had only smooth bottom so it wont take too much friction while pushing forward. Anyway, we were planning a suprise assault somewhere, so we got in and some other people sealed the hatch and lowered the ship into the sea with a loading crane. The inside of the ship was built from two sections, the rear part had a large hampster wheel with axels to the wheels, and I got into the front to steer the submarine. Somewhy, there was a wall between the two sections, but there was a wide hole under the wall so both of us could see the window at the middle of the bottom of the ship. The people at the dock hadnt sealed the hatch with both huge bolts it was supposed to, but it held with one anyway, so they lowered the ship into the water. I heard the water running around the ship, and soon even the eye-window got dimmed as the water blocked the sunlight. The wires got disengaged, and the ship started sinking while my crewmate started walking in the hampster wheel and I grabbed on the handles of the eye. The water was all brown, and no matter where I rotated the ball, I didnt see anything so I left it alone. My crewmate said that we were about to reach the bottom, so I looked at the bottom window. I started seeing something blurry but paler than the water, and withing the same second the sand bottom chrushed against the window. The eerie voice of the impact echoed in the little ship, but my crewmate didnt stop walking in the wheel so we were on our way already. The travel proceeded smoothly with the constant voice of sand swishing against the bottom of the front part of the ship, cut off only by few random rocks those made the ship slow down as it climbed over them. I was a bit worried when the hard rocks hit against the window, but my crewmate said that the glass wasnt built to hold on by its structure, but by its exxaggerated robustness, so I calmed down a bit, but I dont remember what happened then..