The problem of condensation of vapors flowing with high velocity around a horizontal tube is solved for the case of isothermal condition of the wall of a condenser tube. The interfacial shear at the vapor condensate film is assessed with the help of Colburn analogy. Extension of these results in the estimation of average condensation heat transfer coefficients is found to be successful. The present theoretical results are further compared with the recent experimental data and the agreement between the two is found to be very satisfactory. (C) 1997 Elsevier Science Ltd.