Not only attempts to reduce costs but also emissions are driving shipping companies to operate their fleet in slow steaming mode. We show a strategic liner shipping network design decision support system which takes into account three environmental influences: waves, currents and wind. Our model will answers the question, whether environmental influences and the use of additional propulsion systems can influence the cost structure or the on-time delivery of a liner shipping network and its schedule. We will present a variable neighborhood solution approach, that can solve this this network design problem in reasonable time.