Abstract: The present invention refers to a fixed pitch type propeller for vessels, fitted with exchangeable blades and having a central core unit that can be coupled to the transmission receiving the movement from the corresponding engine, and a plurality of blades that surround it in an equiangular distribution and are affixed to the central core; said core (1) has a prism-like configuration with as many faces as blades (2), each of its lateral faces having a groove 6 that ends in a narrowed mouth opening, while the inner ends of blades 2 are each topped by a header (4) that can be coupled to one of the lateral faces of the core unit (1) and fitted midway with a rib (7) that is complementary to the groove (6). The invention also provides means for axial immobilization (3-8) of the headers (4) of the blades respective to the core unit (1).