Can you tell us when Navionics last surveyed the Bahamas? When I corresponded with them in 2005/2006 they would not give out any information pertaining to their activity there but did say they relied on various H.O.'s and their own services. They did emphasize that they did a lot of their own hydrographic work.
Are you referring to nv-charts? If so, nv-charts has split the Bahamas
regions into northwest, central, and southeast which were surveyed last year and this year. You may want to be careful since some places still have older charts
so make sure to check the year!
If you are referring to Navionics, the last major surveys of the Bahamas were done in May 2012. There have been some other minor updates but they're not that important.