In Marshall-Inseln, ships traveling between the atolls and islands of the colony were required to take-on mail, as there was no other scheduled service to the scattered atolls.  These items received manuscript cancellations with the date of receipt and the name of the ship or name of the atoll.

This service was never permitted in Karolinen, but numerous ships carrying passengers and cargo within Marshall-Inseln also made stops in Karolinen.  On occasion, the captains of these ships accepted mail from atolls or islands within Karolinen and used the same procedures as required in Marshall-Inseln.  These manuscript markings were unauthorized and are almost entirely philatelic creations.

Most are from the steamer Diana and contain the name of that ship, but others are known.