Heat-transfer and pressure drop data are presented for turbulent water flow in the annular space between concentric tubes. Heat was transferred to the liquid from the inner surface which was equipped with various surface spoiler configurations. A common outer tube was used which was maintained smooth and adiabatic for all tests. An empirical formula is given which correlates friction factors for circular tubes and annular gaps, or narrow flat passages, with semicircular spoilers on either one or both sides. The use of such friction factors in the Martinelli equation for turbulent heat transfer gives satisfactory estimates of the heat transfer for spoiler configurations.