Star Trek: 10 Things You Didn't Know About Data

A benefit of Data's original android body was that he could add upgrades slowly over time to exceed his limitations. One of these upgrades was the floatation system that he used in Star Trek: Insurrection.

Before this upgrade, Data was too dense to float in water—a fact he apparently learned the hard way. In the second part of the Next Gen episode Descent, we learned of a time when Data was out sailing with Geordi when he decided to go swimming for the first time, only to immediately sink to the bottom of the lake. He was then forced to walk over a kilometre to the shore and spent the next two weeks trying to get the water out of his servos.

In Insurrection, when Data, Picard, and Anij jumped out of the holoship into the water, Data initially sank to the bottom, before rising to the surface and announcing ‘In the event of a water landing, I have been designed to serve as a floatation device.’ It's a silly little scene, but it also shows how Data's abilities have evolved over time.