"Received" stamps are used in many ship's offices to mark correspondence to indicate the date (and often the time) it was received. On occasion these and similar markings (even a few that say "PAID" or "CANCELLED") have also been used to postmark mail, especially when the ship had no operating post office at the time, or no standard postmark was available.
The following postmark is classified as Code RECD
Locy System for Classifying Naval Postmarks, As Revised ©, of the Universal Ship Cancellation Society is excerpted and reprinted with permission.