Use while cruising...

[hvdwolf]

Thus the trip from Boston to Samana cannot be mapped will in any existing products. A straight line does NOT work, since land must be avoided by the ship! Is there any way that RouteConverter can be used both before and after the cruise to keep the record straight as to sailing the ocean blue and taking shore and boat excursions while at ports?

Did you have a look at OziExplorer? I have used it in the past for canoeing, which is basically the same if you follow a meandering river with side streams and want to pass lakes with many small islands: you also plan a route outside the normal route plans. I have been using it with self-made maps (quite easy) and with topographics maps.
I still use it for walking/hiking where I want to plot a route outside the paved roads. (my web tool exports to OziExplorer format, both maps and calibration)