Mediterranean naval powers around the fall of Constantinople

Which naval powers mattered around the fall of Constantinople in 1453?

Venice stood out, but the Ottomans, Spain, Barbary powers, and the Knights Hospitaller also formed a genuinely multipolar maritime environment.

The answer rejects a single-power view of the Mediterranean around the fall of Constantinople. Venice held particular maritime weight through its fleets, trade, and eastern connections. The Ottoman Empire, Iberian powers, the Barbary states, and the Knights Hospitaller also fielded consequential naval forces. Their capabilities and priorities differed, so no one list can be reduced to a simple ranking by battleship-style tonnage. The larger lesson is that a multipolar maritime world is historically more common than a sea dominated by one uncontested navy.