I watched Viking Women And The Sea Serpent without the guys from Mystery Science Theater 3000 talking and it wasn't quite as much fun. It's a 1957 that has an original title that goes like this.
The Saga of the Viking Women and Their Voyage to the Waters of the Great Sea Serpent
It's written by Lawrence L Goldman and Irving Block. Roger Corman is the director and it's an American International Pictures film with a $65,000 budget. He later felt the budget was inadequate to execute what they wanted and said the film taught him an important lesson not to make a big scale movie on a low budget. - The Wikipedia.
It's a simple viking story but the twist is the women are doing the rescuing. Their men have been gone along time so a bunch of the ladies go looking for them. Good thing they had a spare boat in the village. They find the men, now prisoner of a king, working as slaves in a mine. They get caught, they escape, there's fighting and drinking. Eventually they go home.
Sadly, it lives up to it's deserved score of 2.8 on the IMDb. The sea serpent is best left unmentioned. On the bright side, it's short, only 66 minutes. AIP isn't a company known for giving the viewer much of a return for their dollar. It was released as a double bill with The Astounding She-Creature. I have that to watch soon. I'm just a glutton for punishment but I haven't seen it since the 90s so what the heck.
I like this story from the IMDb trivia page for the movie:
Susan Cabot recalled an incident that happened during the scene where the Viking women first set out in the boat to look for their men. She said that there were 11 women in the "Viking ship", which was being towed out to sea by a boat that was out of camera range. When the scene was over and the towing boat was supposed to stop, they discovered that the man piloting the tow boat had fallen asleep, and no matter how loudly they yelled at him to wake up, the sounds of the ocean drowned them out. The bottom of the "Viking ship" began to fill up with water, and out of the 11 women on the sip, only Cabot and Abby Dalton could swim. They finally caught the attention of two passing surfers, who took a couple of the girls and headed to shore, but by the time the rest of the girls and the boat reached land, which was the base of a cliff jutting out into the ocean, the tide was beginning to rise and the sand at the base of the cliff was quickly being covered over by water. The girls had to climb up the face of this cliff, with the water slowly rising after them, until they got to the top of it. There they ran into some film-crew members who had been searching for them, and they took the girls back to the set on buses.