I know that you can crate a vessel. So you can have it unpack or the Ummu unpack. But I don't think you can pack them back into a crate, right?
Like for my C57D I was thinking a Tractor vessel could be packed in a crate. They unload the crate and then unpack. Do what you have to and then pack into a crate a load it.
The same for a Chariot for the Jupiter 2
It needs to be a vessel so you can use attachment.