A rotor (106, 200) for use in a fluid filled housing of a subsea electric machine system, the rotor (106, 200) comprising: an elongate cylindrical rotor hub; a plurality of permanent magnets arranged around a circumference of the rotor hub; and a rotor sleeve around the permanent magnets adapted to seal the permanent magnets against contact with the fluid in the housing, the rotor sleeve providing primary radial support for retaining the permanent magnets to the rotor hub during operation of the rotor (106, 200); characterized by further including end rings at axially opposing ends of the rotor hub, the inner surface of the end rings abutting the end of the rotor hub and providing axial support to the permanent magnets; wherein the rotor sleeve is constructed from a two layer fiber-reinforced composite including an outer and inner layer, the inner layer includes a plurality of latitudinal, adjacent, non-overlapping spaced-apart composite hoops, residing between the outer surface of the rotor hub and the outer layer; the outer layer has a greater density of axially-oriented fibers than fibers of any other orientation and a cylindrical end treatment strip of composite material capable of bonding to the sleeve, wherein a ledge is provided circumferentially on the outside diameter of the end ring, and wherein the ledge serves as a landing platform for the positioning of the end treatment strip, which is wrapped around said end ring's ledge; and on each end ring, a seal sealing between the end ring and the end treatment strip. an elongate cylindrical rotor hub; a plurality of permanent magnets arranged around a circumference of the rotor hub; and a rotor sleeve around the permanent magnets adapted to seal the permanent magnets against contact with the fluid in the housing, the rotor sleeve providing primary radial support for retaining the permanent magnets to the rotor hub during operation of the rotor (106, 200); characterized by further including end rings at axially opposing ends of the rotor hub, the inner surface of the end rings abutting the end of the rotor hub and providing axial support to the permanent magnets; wherein the rotor sleeve is constructed from a two layer fiber-reinforced composite including an outer and inner layer, the inner layer includes a plurality of latitudinal, adjacent, non-overlapping spaced-apart composite hoops, residing between the outer surface of the rotor hub and the outer layer; the outer layer has a greater density of axially-oriented fibers than fibers of any other orientation and a cylindrical end treatment strip of composite material capable of bonding to the sleeve, wherein a ledge is provided circumferentially on the outside diameter of the end ring, and wherein the ledge serves as a landing platform for the positioning of the end treatment strip, which is wrapped around said end ring's ledge; and on each end ring, a seal sealing between the end ring and the end treatment strip. further including end rings at axially opposing ends of the rotor hub, the inner surface of the end rings abutting the end of the rotor hub and providing axial support to the permanent magnets; wherein the rotor sleeve is constructed from a two layer fiber-reinforced composite including an outer and inner layer, the inner layer includes a plurality of latitudinal, adjacent, non-overlapping spaced-apart composite hoops, residing between the outer surface of the rotor hub and the outer layer; the outer layer has a greater density of axially-oriented fibers than fibers of any other orientation and a cylindrical end treatment strip of composite material capable of bonding to the sleeve, wherein a ledge is provided circumferentially on the outside diameter of the end ring, and wherein the ledge serves as a landing platform for the positioning of the end treatment strip, which is wrapped around said end ring's ledge; and on each end ring, a seal sealing between the end ring and the end treatment strip.