A "shrouded propulsor" is a ducted propeller (aka "shrouded propeller configuration" or pump-jet). The advantage of a pump-jet is that it minimizes acoustic waves in all directions except directly rearward. The disadvantage is a higher acoustic signature directly behind the torpedo's or submarine's shrouded propulsor. PLAN holds 'largest-ever' firepower display in SCS drills | IHS Jane's 360 "The new torpedo appears to be longer than the PLAN's standard Yu-7 lightweight torpedo, possibly with an extended homing and data processing section. Another notable difference is that the weapon seems to have a shrouded propulsor in place of the contra-rotating propellers on the Yu-7, which may significantly reduce the noise radiated by the torpedo, making detection more difficult." [(See picture above) Yu-7 lightweight torpedo with a "shrouded propulsor" at the rear end of the torpedo.] ---------- Old technology. "The contra-rotating propeller section of a Yu-1" torpedo. ---------- New technology. Shrouded/ducted propeller.