Hi, I am trying to show service area reachable by boat at sea. I have a point on land as a boathouse I wish to be able to determine how far the boat can get in a given time at a give speed e.g. 25 knots in 30 minutes) in all directions taking into account obstructions (headlands, reefs etc). This will not follow shipping lanes, so cannot use Network Analyst. Has anyone done this or something similar? If so how!? Thanks.