I was in the Navy once, several, several years ago. We used a term there, “Gods Speed”, to wish a person well. It’s one of my favorite sayings. As I wrote it today, I wondered, “Were did that come from”. As it turns out, it’s not a Nautical term at all. The following excerpt fromWORDS@RANDOM explains the saying.
Be Well, Successful, Gods Speed,
Stephen G. Bergkamp

God Speed
Bill Roskopf writes:
I understand “Godspeed” to mean good luck, but what is its origin?
The word Godspeed is used to wish a person good fortune or success, as on starting a journey, a new business, etc. It is usually found in expressions of the sort “to bid (a person) Godspeed.”
A few examples: “Evangelist, after he had kissed him, gave him one smile, and bid him God-speed. So he went on with haste…” (John Bunyan, Pilgrim’s Progress); “‘I’m wishing you God-speed, Hattersley,’ cried Arthur, ‘and aiding you with my prayers’” (Anne Brontë Tenant of Wildfell Hall); “Rowland at the garden gate was giving his hostess Godspeed on her way to church” (Henry James, Roderick Hudson); “Eight years before he had seen his friend off at the North Wall and wished him God-speed” (James Joyce, Dubliners).
Godspeed is a nominalization of the phrase God speed (you), understanding which depends on two things: speed in this sense means ‘to prosper; succeed’, which is now archaic, but which is the original sense of the word; and the verb is subjunctive, expressing a wish, with the entire phrase meaning “may God cause you to succeed.” Semantic parallels are such common expressions asGod bless you or God forbid!; another nominalization is goddamn (as in “I don’t give a good goddamn what you think”), shortened from God damn you.
The word Godspeed (which can also be written God-speed) is from Middle English, first found in personal names in the thirteenth century.