Dangerous adventures in Saint Petersburg

This summer I with my family decided to spend some time in St. Petersburg in Russia to have a little trip. Let's talk immediately about the occasion, that was happening with us yesterday. We were walking through the center of the city and decided to have a two hour long voyage on the Neva river. The vessel was big and almost all people were sitting on the top, where were placed benches. 

Some benches were placed versa to others and thus some people were sitting on the contrary with the vessels way (face to the ship's tail). Neva river has a lot of small bridges like on this picture. The story actually about them.

The vessel's speed was over 40 km/h. We have successfully passed two or three bridges. I was looking around and listening to guide's stories about sightseens. I literally stuck watching on rivers's stream. Suddenly my brother, who was sitting near me shouted: "WOW!". This made me leave from stucking condition and I just by human instinct crouched down. We were under the bridge approximately 4 seconds and only after we passed it, I've realized what just happened. When we were under the bridge I heard something kind of knock. Only when I saw a man, that was holding his back of the head with a hand, I understood everything. This man was sitting on the bench, that was turned to the tail of the vessel, so he couldn't see that bridge. The situation was horrible. The man stood up and went to the first floor of the ship to get medical care. There was blood on his hand. Some people even said that he lost some teeth after hitting. Actually, I thanks my brother for his yell. If he wasn't, it could happen something terrible to me, as I crouched at the last moment.

After ten minutes of hype we were close to the next bridge. From afar the bridge was rather high. Nothing doing! The next bridge was even lower than previous. All people were scared and with closing to the bridge we more and more realized that we can not to pass. We were very exited and started to lie down to the floor to prevent the hitting with iron bridge and fortunately we successfully sailed out from that dangerous zone. 

Under the bridge, lying on the floor, I looked up and saw that the distance between the bridge and the top of the benches was approximately 10 centimeters (0.33 feet or  3.9 inches). The view from the floor was something like in the picture below.

All this was caused by the flood of the water that maybe was caused by the recent rains. Captain said that such situation was first in the history of his vessel. 

The moral of this story is that don't be fully relaxed in the environment where something can happen. Also, sit only on seats that allow you to spectate a road or a way. This gives you a possibility to save yourself or other people.  Always be aware about everything that happens around you. 

P.S. Sorry for mistakes. I'm not English) I'm just learning it)