A note on generalization of Zermelo navigation problem on Riemannian   manifolds with strong perturbation
  We generalize the Zermelo navigation problem and its solution on Riemannian manifolds $(M, h)$ admitting a space dependence of a ship's speed $0<|u(x)|_h\leq1$ in the presence of a perturbation $\tilde{W}$ determined by a strong velocity vector field satisfying $|\tilde{W}(x)|_h=|u(x)|_h$, with application of Finsler metric of Kropina type. 
Piotr Kopacz
math.DG math.OC