Could neutral minor navies have changed World War II?

Which uninvolved minor navies could have made a difference in World War II?

Sweden is the clearest candidate. Turkey prompts disagreement: Yavuz, destroyers and straits access offered useful options, but supporting Turkey could cost either coalition more than it gained.

Turkey's case rests on opening the straits, adding Yavuz and modern destroyers, and giving a coalition access to the Black Sea. Those ships could reinforce convoy protection or release other capital ships for service elsewhere. The counterargument is that mixed equipment, dependence on foreign spares and exposed geography would make Turkey a costly ally to sustain. Rearming its forces and defending new land fronts could outweigh the naval contribution. Sweden had limitations of its own, but its industrial base made it more self-supporting. Allied control of Narvik would provide a route for sustaining Swedish participation. The disagreement turns on whether extra ships and strategic access justify the accompanying support burden.