Sure, but it's hard to argue that it is a better result than if you paid those same dock workers for building schools, out of that same government money, or if

Sure, but it's hard to argue that it is a better result than if you paid those same dock workers for building schools, out of that same government money, or if instead of a destroyer they were housing a fleet of cargo ships used for commerce. In the best possible case, seeing military spending as economic stimulus amounts to "we will use the fear our citizens have of other people to institute backdoor and inefficient redistribution and science research programs; because we failed at getting them to consent to fund those same goals directly out of care for others." Of course, this assumes economic stimulus is really the main reason for military spending, which is probably not how the people in charge of these programs see it.