I remember reading a story in the Greenies Universe in which a Martin family who are on Earth (in West Hem) and have to flee to Mars. They do it by boat in the Caribbean to get to East Hem where they have a contact.
I can't find the story and it doesn't seem to appear in the Story List for the universe.
Help please.
Look up Rlfj's page; he wrote three more sequels to Greenies.
https://storiesonline.net/universe/214/greenies-a-perfect-world
Argon is on the right track. You'll find it in Martian Vengeance. For full context read Martian Justice first.
Ah! Thanks. That is it. I've been re-reading the whole series but for some reason thought it was in a stand alone short story.