The existing design methodologies generally rely on experience and the design-test-modify process to fulfill the urgent requirements of shaftless rim-driven thrusters for low and medium speed, high load capacity, and wear-resistant water-lubricated bearings. In order to innovate current design methods and improve the design capabilities of such bearings, this paper conducts research on the lubrication structure design of water-lubricated spiral groove rubber thrust bearings (SGRTBs). Furthermore, the model developed in this paper takes the effect of surface roughness into account, proposes a mixed lubrication analysis technique for water-lubricated SGRTBs, achieves the optimization design of the spiral groove structure parameters (spiral angle, groove width ratio, number of spiral grooves, and tilt angle), and addresses the mixed lubrication issue of typical spiral surface contact.