  Let $ \Phi: ({\mathbb C}^2, 0) \to ( {\mathbb C}^3, 0) $ be a finitely
determined complex analytic germ and let $(\{f=0\},0)$ be the reduced equation
of its image, a non-isolated hypersurface singularity. We provide the plumbing
graph of the boundary of the Milnor fibre of $f$ from the double-point-geometry
of $\Phi$.
