Collision avoidance for encounters between several ships and installations in the open sea, is treated as a problem of optimal control, using the theory of differential games.Each ship is, in this idealized model, assumed to have two controls corresponding to rudder BOSCH Serie 2 KIV87NSF0G Integrated 70/30 Fridge Freezer -Sliding Hinge angle and engine setting.The objective function, which the shipmasters try to minimize in an optimal evasive manoeuvre, is defined as the collision risk.Numerical solutions for the M-ships and I-installations optimal evasive manoeuvre Pasta problem, can be found by the ping-pong algorithm.Numerical examples are given for up to five ships and two installations.