The analogy is useful but I think at this point overused and does not really succinctly dissolve the question as it would first seem.

First of all, you actually can answer the question of "does a submarine swim", in all sorts of ways. You simply have to be more specific and define your terms. Submarines achieve neutral buoyancy and traverse water. They generate power to do so through nuclear reactors rather than cellular respiration. And so forth. I think the point of the analogy is really to illustrate that swimming, like thinking, is partly defined the actor being humans - but then, what should we call the equivalent of non-human thinking?

It seems like a very large stretch to suppose that brains are doing something noncomputable, or that biology has happened upon some metaphysically unique substrate for preforming computations. So, even though we can't agree and don't even know what we mean by "thought", there is good reason to believe that a computer can do the same sort of thing, at least in principle.

When I say "same thing" - obviously not the same exact thing, but in whatever sense it is that we care about. To go back to the submarine analogy, if we knew that what we cared about was "traversing water", then we might feel justified in saying that steel and carbon can both accomplish that feat.