Recently there is an increasing tendency that the duct propeller is adopted in large vessels for improvement of the propulsion efficiency. With this tendency, many reports and papers on the propulsion efficiency of the duct propeller have been published. However, there are seen few reports or explantations on the points in the work for adoption of the duct propeller at ship's new building or repairs. We, Kawasaki Heavy Industries, Ltd., adopted the duct propeller in a large vessel first in the world, and have examined various problems attending upon the work and settled them. Among those, we wish to introduce the following four main items: 1. Fitting accuracy of duct 2. Shape and strength of appliance for carrying-in the propeller 3. Process of carrying-in the propeller 4. Drawing procedure of propeller shaft in the dock