[thackney]

The “boat” didn't sink because too much water was put on it.

This was a semi-submersible rig. The rig floated due to the buoyancy of the pontoons. Those pontoons are underwater. Pouring water on the surface equipment that doesn't hold water did not make it sink.

[dmet]

What other reason would cause it to sink other than water in the pontoons?. You dont see a scenario that water on the decks would have found some way to the pontoons?