Task: Translation
Input (Xhosa): Ngamadonga azo angqingqwa zimele ukusebenzisa kubunzulu bamanzi alungele umqhubi; kodwa kufuneka amandla amancinci ukugcina ukuseleko-moya.
Output (English): With their fixed sidewalls they are restricted to operation in depths of water that are suitable for the propeller, but require much less energy to maintain the air cushion.