Today we are flashing back to September 1924 and January 1961 and the history of the Submarine Insignia

Evening star. [volume], September 28, 1924, Page 11, Image 57
Army and Navy News by M. H. McIntyre

Announcement was made this week by the Bureau of Navigation, Navy Department, prescribing the qualifications for officers and enlisted men for wearing the submarine insignia, which was approved by the Secretary of the Navy last March.”(a) Officers qualified for submarine command in accordance with chapter 3. Paragraphs 203-209, Submarine Instructions, November. 1919,”are authorized to wear this insignia. The insignia will be worn at all times by the commissioned personnel as specified in (a) while they are attached to submarine units or organizations ashore or afloat, but it may not be worn at any time by officers when not attached to submarine organizations.


The following enlisted men are authorized to wear this insignia: (a) Men found qualified for submarine duty in accordance with chapter 3. Paragraphs 214-215. Submarine Instructions, November, 1919, whose certification of qualification appears on their service records.
(h) Men who prior to the issue of Submarine Instructions, November 1919 were found qualified for submarine duty and whose certification of qualification appears on their service records.

One of the earliest versions of the submarine warfare insignia, circa the 1920s. https://theleansubmariner.com/2018/10/19/submarine-dolphins-part-three-the-artists-that-created-the-insignia/

As specified in (a) and (b) the insignia will be worn at all times by enlisted men while attached to submarine units or organizations, ashore or afloat. Enlisted men will not be authorized to wear this insignia if they are not attached to submarine units. A change in the Uniform Regulations covering the details of the insignia and the manner of wearing it is in course of preparation and will be issued to the service shortly.
These qualifications will be incorporated in the Bureau of Navigation Manual when reprinted.

ALL Hands Magazine JANUARY 1961
Dolphins

“A high point in the career of many a Navy man occurs when he becomes a qualified submariner. At that time he is authorized to wear dolphins.
The correct name for the dolphins is submarine insigne. It is one of the items of uniform included under the category of breast insignia, including naval aviator, aviation observer and parachutist insignia, among others.
The submarine insignia came into use in the Navy nearly 37 years ago. It was on 13 Jun 1923 that the commander of a New London-based submarine division, took the first official steps—by way of an official recommendation. That officer was Captain Ernest Joseph King, USN, who later became Commander-in-Chief U.S. Fleet and Chief of Naval Operations.
Captain King recommended that a distinguishing device be adopted for qualified submariners, both officers and enlisted men. With his recommendation he submitted a pen-and-ink sketch of his own. The sketch showed a shield mounted on the beam ends of a submarine, with dolphins forward of, and abaft, the conning tower. The recommendation was strongly endorsed by Commander, Submarine Divisions, Atlantic Fleet, the following day and sent on to the Chief of the old Bureau of Navigation.
Over the next several months the Bureau solicited additional designs from various sources. Several were submitted. Some combined a submarine-and-shark motif. Some showed submarines and dolphins. Some used a shield design.

On 20 March 1924, the Chief of BuNav recommended to the Secretary of the Navy that the dolphin design be adopted. A few days later the recommendation was accepted by Theodore Roosevelt, Jr., Acting SecNav.
The final design shows the bow view of a submarine proceeding on the surface of the sea. Her bow planes care rigged for diving. Flanking the submarine are stylized dolphins in horizontal position with their heads resting on the upper edge of the bow planes.
As with other breast insignia (and enlisted distinguishing marks), qualifications are outlined in the Bupers Manual, while the method of wearing, a description of the design and an illustration of the design are to be found in Uniform Regulations.
The submarine insignia in the early days were awarded only to those officers qualified for submarine command. Later the criteria became “Qualified in sub- marines.” Also in the early days, the insignia were worn (both by officers and enlisted men) only when attached to submarines or submarine organizations. Under current directives however, once qualified, the insignia may be worn regardless of the duty being performed.
As first authorized, the insigne for officers was a bronze, gold-plated metal pin. Later, both a gold embroidered insigne and a gold-color metal pin became authorized.
Today enlisted submariners may wear either a silver-color metal pin or an embroidered dolphin. The latter is either white or blue, depending on the uniform worn.
Originally, the embroidered insigne was worn on an enlisted man’s right sleeve, midway between the wrist and elbow. To day it is worn on the left breast.”