We consider the problem of a long thin weightless rod constrained to lie on a cylinder while being held by end tension and twisting moment. Applications of this problem are found, for instance, in the buckling of drill strings inside a cylindrical hole. A critical load was found where the rod coils up into a helix. Here the anisotropic case is studied. It is shown that the equations are no longer integrable and give rise to spatial chaos with infinitely many multiply looped localised solutions.
Helices become slightly modulated.