D-16 



UNDERWATER TRENCHER 



Function : Pipe trenching and excavation for construction foundations. 



Operating Depth : TOm (230 ft) 



Dimensions (LxWxH) : 11.9in x 5.2m x U.9x (39 ft x 17.1 ft x l6.1 ft) 



Weight (Dry) : 60t (66 tons), in water - 50t (55 tons) 



Speed : 3km/hr (1.6 knots) (travelling speed on bottom) 



Pover : Diesel generator transmits kko V, it is raised to 3,300 V, 60 Hz 



"by transformer, this power is reduced to UUo V and 110 V when it reaches 



the vehicle. 



Propulsion : Caterpillar tracks, driven by two hydraulic motors. 



Tools/Instrumentation : Five blade cutter and dredge pump (discharges 



sediment 200m from cutter). 



Navigation : A bottom-mounted, acoustic system consisting of three beacons 



which ping on surface command and a receiver (hydrophone) on the trencher 



which receives the three pings. Surface processing of this data provides 



a position based on (3-range) triangulation. 



Shipboard Components : Display/control console, diesel generator. 



Support Ship Requirements : Eighty (8o) ton crane (minimum) for launching 



trencher. Deck space for crane and umbilical, and enclosed space for 



display/control console. 



Status : Developed as a prototype machine in 1973. Demonstration 

 experiments were conducted in 1975? it has not been used since and there 

 are no plans for future work. 



Builder /Operator : Sumitomo Heavy Industries, Ltd. 



Tokyo, Japan 



