Three Strange Triangle Above The Baltic Sea

This is my first tour to explore in the Baltic Sea. When my friend and me watch through the window of the ship and suddenly found the three awesome triangle above the Sea. It is a really strange something above the sea. When My friend and me looked closely, they go up and down a little. My friend can not explain what it is. It is just look like the balloon or something else. However, I think it is a strange something look like UFO, but my friend said it is not UFO.

amazing three triangle above the sea
amazing three triangle above the sea 01