"Sailor on a Horse" and Smoke Signal

Long ago I saw the end of a movie or television episode when a western fort was being attacked. The soldiers opened a gate and slid a raft down to the river and escaped on the raft. And I remembered that the soldiers wore Mexican War era caps instead of normal cavalry hats.

I thought that it was an episode of Death Valley Days.

Since Death Valley Days episodes were based on real events, I figured that there should have been a historic event vaguely similar to what I remembered from that scene, if it was an episode of Death Valley Days.

Years later I read about Fort Madison, Iowa, built in 1808 and attacked several times by Indians. It was attacked in April 1809, March 1812, besieged in September 1812, and besieged again beginning in July 1813. The soldiers abandoned the fort during the last siege, possibly in September 1813. They set fire to the fort buildings and escaped in the dark through a trench to the Mississippi River and sailed away in boats.

So for many years i wondered if the Death Valley episode was based on the abandonment of Fort Madison, Iowa.

I recently saw Smoke Signal (1955) in which soldiers abandon a fictional fort, the river outpost, under attack by Utes allied with Navajos and Sioux and travel hundreds of miles down river in boats to safety. I wondered if I remembered the scene where the soldiers escaped in boats from Smoke Signal. Did I really remember seeing Smoke Signal on television? Did I remember an episode of Death Valley Days that used that scene from Smoke Signal?

On May 23, 2019, I saw part of the "Sailor on a Horse" (17 January 1959) episode of Death Valley Days. The IMDB gives the plot as: "A US Navy officer is assigned to chart the Missouri River, but he runs into some unexpected hostility from a bull-headed army officer." In the part that I saw, naval Lt. Drysdale warned Major Creel at Fort Benton that the Sioux and Assiniboine were uniting to attack the fort. Drysdale had boats secretly built. When the Indians attacked they opened the water gate and put the boats in the river to sail downstream to Fort Union. The soldiers wore cavalry hats but Drysdale wore a sailor's cap.

So it seems that "Sailor on a Horse" was probably what I remembered. But was it based on the abandonment of Fort Madison in 1813, or on something that actually happened at Fort Benton, Montana, a trading post from 1846-1868, and an army fort from 1869-1881?