The Zinc modelling language provides a rich set of constraints, data structures and expressions to support high-level modelling. Zinc is the only modelling language that supports all solving techniques: constraint programming, mathematical methods, and local search. By providing search patterns, it allows users to implement their search methods in a declarative way. There are currently three search patterns implemented in Zinc: backtracking search, branch and bound search, and local search. In this paper we explain how Zinc efficiently implements user-defined local search algorithms.