HMAS Perth (D 38) For other ships with the same name, see HMAS Perth. HMAS Perth (D 38) was the lead ship of the Perth class guided missile destroyers operated by the Royal Australian Navy (RAN). Built in the United States of America to a modified version of the Charles F. Adams design, Perth entered service with the RAN in 1965.
If you really want the postcards to arrive quickly, it will cost few pennies more, but putting it in an envelope and sending a first class letter, assures quick delivery from anywhere in the world. First class letter - 3-7 days. postcard - 7-14 days-sometimes never. USNR, e-mail is just not the same.
Certified mail generally takes as long as it takes for the receiver to be present to sign for it. In your case, I would say about three days, but again someone must be at the location for delivery to sign for it. The mailman will try to deliver it a couple of times, and then it will end up back at the post office for you to pick up there.