Abstract: An improved hydraulic knife assembly is provided for cutting potatoes and the like, wherein the knife assembly includes a cross-cut knife used to facilitate removal of a stuck potato. The knife assembly comprises a grid of knife blades encased within a knife housing adapted for removable in-line mounting along a flow conduit. Potatoes are propelled through the flow conduit by an hydraulic flow stream for cutting engagement with the knife blades as the potatoes pass through the knife housing. In the event that a potato becomes stuck at an upstream side of the knife housing, the cross-cut knife is receivable through an open slot formed between the knife housing and the adjacent end of the flow conduit to sever the stuck potato and thereby permit substantially unobstructed disassembly of the knife housing from the flow conduit. The thus disassembled knife housing and flow conduit can then be cleared preparatory to re-assembly and resumed normal cutting operations.