I found a solution. There is a service
that unzips files and posts the results. you can then download individual files or the group of files in a. zip format.
Just copy the link to the file you want to unzip and load it into
So far I have managed to get a few small catalogs downloaded and into Opencpn
wobzip managed to unzip the 408 mb file for the South Pacific
and now I just have to convince my phone
to download a 1.1 gb file and unzip it. of course I could individually download all 3800 files. hmmmm
It would be so nice to have catalogs better indexed into small file sizes so I don't have to download thousands of files when I just need a few.