Wikipedia
Hawsepiper is an informal maritime industry term used to refer to a merchant ship’s officer who began his or her career as an unlicensed merchant seaman and did not attend a traditional maritime college/academy to earn the officer license. In the United States, after accumulating enough sea time in a qualified rating, taking required training courses, and completing on-board assessments, the mariner can apply to the United States Coast Guard for a license as a Third Mate or Third Assistant Engineer. If approved the applicant must then pass a comprehensive license examination before being issued the license.
A ship’s hawsepipe is the pipe passing through the bow section of a ship that the anchor chain passes through. Hawsepiper refers to climbing up the hawsepipe, a nautical metaphor for climbing up the ship's rank structure. This is in turn derived from the traditional British Naval usage of "came up through the hawsehole," referring to sailors who first entered the ship as foremast jacks before becoming officers, metaphorically by climbing up the hawser without great honor or respect, rather than being received directly onto the quarterdeck. There is also the phrase, "going down the hawse pipe" which is an officer who cannot find a ship's billet and signs on as an ordinary seaman or wiper. Several merchant seamen’s unions offer their membership the required training to help them advance. Similarly, some employers offer financial assistance to pay for the training for their employees. Otherwise, the mariner is responsible for the cost of the required training.
Since the requirements of STCW '95 have been enacted there have been complaints that the hawsepiper progression path has been made too difficult because of the cost in time and money to meet formal classroom training requirements. These critics assert that the newer requirements will eventually lead to a shortage of qualified mariners, especially in places like the United States.
The U.S. military rough equivalent to this term is mustang.