The Elco 77ft PT-20 was the lead boat of 49 Elco 77ft PT boats. The class was the first PT boat of Elco’s design to enter mass production and would serve as a basis for the larger Elco 80ft PT boats. As for the PT-20, it was laid down at the Elco shipyard in Bayonne, New Jersey on 14 October 1940, launched on 14 March 1941, and commissioned on 20 June. The PT-20 later saw action during two important battles of the US Navy: the Attack on Pearl Harbor on 7 December 1941 and the Battle of Midway between 4–7 June 1942, during which it was deployed for anti-air duties. After Midway, PT-20 returned to Pearl Harbor and was decommissioned on 22 December 1944 due to its obsolescence, with its final fate unknown.

The PT-20 was introduced in Update 1.77 "Advancing Storm". Compared to the reserve PT-6, it offers a noticeable upgrade in every aspect: it has double the machine guns and torpedoes, offers significantly better mobility, and is smaller in size. Although the four Browning MGs are capable of dealing with other thin-skinned boats and aircraft, their effectiveness is restricted due to awkward gun placement, with the boat’s bridge obstructing the frontal line of fire. In addition, the PT-20's wooden hull is quite fragile, especially from the sides, making it vulnerable to returning fire.