Abstract: To accomplish a special mission under water, a submersible is oft,.n required to have movements and opqrations with sip degrees of freedom besides those needed by a conventional submarine. In order to study and analyse the manoeuvre and control characteristics of the submersible, a quarter scale self-propelled submersible model, telecontrolled by the radio,has been made. The model with a displacement of one ton is 3.8m long and 0.65m wide. The manoeuvre on horizontal and vertical planes and some special manoeuvre operations of the submersible have bean performed in a towing tank, including hovering, lateral translation, turning on the spot and mating with another construstion underwater. The present paper lays special stress on analysing the control characteristics of the ducted propeller, and some comments on the manoeuvre characteristics of the submersible are also made, All these may be useful for research workers on a submersible.