Based on the Coast Guard Historian’s timeline, https://www.history.uscg.mil/research/chronology/
With inspiration from Mike Kelso

April 22

1944  Coast Guardsmen participated in the invasions of Aitape and Hollandia in Dutch New Guinea.

The 82-foot patrol boats of Squadron One (RONONE) deploying from Subic Bay in the Philippines to the theater of operations in Vietnam. (U.S. Coast Guard)

1965  The Coast Guard and the Navy agreed on the deployment of 82-foot patrol and 40-foot utility boats to support Operation Market Time in Vietnam.

CG Squadron 3 enroute Subic Bay, 1967, Vietnam War

April 23

1790 The Secretary of the Treasury Alexander Hamilton submitted a report to Congress suggesting the utility of building “ten boats for securing the collection of the revenue.” Hamilton’s suggestion was accepted and passed into law on 4 August 1790 after the bill was signed by President George Washington.

1880 Captain Jerome G. Kiah and his crew of six surfmen from the Point Aux Barques Life-Saving Station responded to a distress signal from a stranded scow in Lake Huron.  They departed their station in their pulling surfboat but the boat capsized a number of times in the icy water, eventually causing the six surfmen to perish from hypothermia.  Only Captain Kiah survived the ordeal, but was severely injured from the cold water and forced to resign from the Service.  He carried the psychological scars of the disaster for the rest of his life, but rejoined the Life-Saving Service later that year as District Superintendent.

1924  A tube transmitter for radio fog-signal stations, developed to take the place of the spark transmitters then in use, was placed in service on the Ambrose Channel Lightship and proved successful.

2007  The Intelligence Specialist (IS) rating was launched with a special ceremony at Coast Guard Headquarters.