Railguns, Gauss guns, and imperfect naval innovation

What major naval advance is most likely over the next fifty years?

The forecast favors a practical railgun or Gauss gun, with the railgun considered more likely because it offers better aiming control.

A personal forecast favors a practical railgun or Gauss gun as a major naval advance over the next fifty years. The railgun is considered more likely because it can be aimed more readily, although a simpler Gauss gun might also become usable. Useful systems can be rejected because they fall short of perfect performance at introduction. Several ninety-five-percent solutions might together meet a requirement that none satisfies alone. Demanding perfection from the outset can leave no usable system available.