In this paper, an analysis of the internal water-cooling of a gas turbine was carried out. The density differences due to heating of the water in the blade and drum, combined with the very large force field associated with the centrifugal force caused by the rotation of water, sets up strong convection currents, which resulted in a very efficient heat transfer. Using the Havier-Stoke's and the continuity equations, applying Prandtl’s analogy between heat transfer and fluid friction and von Karman's - Nikuradse’s universal velocity distribution equation, the coefficient of heat transfer was derived and the maximum gas effective temperature predicted. For the conditions used in this investigation the following enumerated results can be stated: 1) The computed coefficient of heat transfer between cooling passage wall and water is 3850 Btu/(hr)(sq ft) (°F). 2) The rate of coolant flow is 11.35 lb/sec. 3) The effective gas temperature is 2510°F, assuming no radial heat flow alone the metal parts. 4) The average blade temperature is 600°F. 5) The blade has one cooling passage 4" long and .25" in diameter, and one equivalent in half to it in the cooling effect. / Master of Science