An underwater trenching apparatus for burying pipeline and the like including a frame for positioning about the pipeline to be buried, a drive roller system operatively connected to the frame for driving the frame along the pipeline and including at least one pair of opposed rollers, each of the rollers having a curved pipe contact surface having a radius less than the radius of the pipeline to be buried and configured to grasp about 40 percent of the circumference of the pipe, the arms to which the rollers are mounted pivot about a shaft which is removably mounted to the frame, and a cutting system attached to the frame for cutting a trench, the cutting system includes at least one pair of rotating discs rotating about a horizontal axis, and having water nozzles extending out from them, the water forced out of the nozzles scoops the seabed and disperses it up, away from the bottom of the trench. The pair of discs are mounted so that they can be moved up and down as well as rotated in and out. An eductor system for drawing up portions of cuttings cut by said cutting means in the trench and discharging these portions away from the trench can be mounted on a carriage separate from the frame which is pulled a distance behind the frame.