Many moons ago I bought the Navplanner software from Navionics. This enables you to do all your navigation stuff on your laptop & load it onto your plotter. Having just got the new boat rigged, I wanted to transfer all my old waypoints from the old boat to the new boat, so I fired up the ancient desktop & dug out the old software. Cut a long story short, Navionics have sold off the rights to the software to Navigation Planner
who now offer upgrades to the latest version for a very reasonable £36. I bit the bullet & upgraded. The new version is worlds apart from the old Navionics version. For starters you only need to plug in your chart card once & the charts are copied to your computer. You can now browse the chart, plot waypoints, routes, see tides & basically have all the functionality of the chart on your laptop. The software will import, convert, save & export data from just about any plotter out there; once you suss out how to do it at the plotter end that is
I think its a cracking bit of software for a very reasonable price.