All this from a Military Branch smaller than the New York City Police Department…..
The Coast Guard played a significant role in securing Vietnam's 1,200-mile coastline. Some 8,000 Coast Guardsmen and 56 different combatant vessels were assigned to duty there. Coast Guardsmen destroyed enemy supply ships, supported ground units, rescued American and other friendly forces, and performed many more duties, including carrying out humanitarian roles which are common to the Coast Guard.
The patrol boats also worked with the Navy SEAL's and recon units. They also gave emergency support to Special Force's camps, transported personnel, evacuated wounded and provided naval-gunfire support. About two years into Operation Market Time, naval operations were extended further off-shore and expanded into the Gulf of Thailand.
As time went on, the Coast Guard was asked to increase its support and did so by providing five high-endurance cutters ranging in size from 255 to 378 feet. Coast Guard Squadron Three was born. The large cutters kept their peacetime white paint job instead of taking a coat of gray, like the patrol boats. They were quickly nicknamed "White Ghost" by the Viet Cong
Shortly after their arrival, Squadron Three ships began battling the Viet Cong. The cutter Rush, working with an Australian destroyer, brought its guns to the aid of a small Special Forces camp in the village of new Song Ong Doc. The village, located in the middle of Viet Cong held territory, was being overrun. Gunfire from the two ships drove off the attackers and left 64 Viet Cong dead. Like the patrol boats, the large cutters were multi-mission ships. They supported amphibious assaults and gave logistical support for Coast Guard patrol vessels and the Navy PFC's (Patrol Craft Fast).
By the time they left, Coast Guard cutters had cruised over 5.5 million miles, participated in nearly 6,000 naval gunfire missions, and boarded nearly 250,000 junks and sampans. They also helped stop more than 300 tons of ammunition from reaching the guns that fire at other Americans.
http://www.jacksjoint.com/cgvietnam.htmhttp://www.uscgc-rockaway.org/cogard/cogard.htmI never saw combat but I did serve aboard one of the most sophisticated anti-submarine warfare ships at the time. The USCGC Jarvis. However, the most action we saw from her torpedo tubes was launching basketballs into downtown Honolulu a ½ mile away.