BSB4 Raster charts

[cruiserone]

Dare I ask.

Like many, I have for a number of years used a Auto GPS (satnav) to get about over land. But have used a number of forums to download a unpaid maps of your choice.

Now I want to do the same for cruising around the UK using a GPS plotter. But cannot find any such marine GPS forums to do the same for a BSB4 Raster chart.

Are any such places.

thanks