A Hunting Will We Go - June 18, 1976 - S3-E18
Other mistake: The episode takes place in Arkansas, but at one point Sam is in a telephone booth and very tall mountains are behind him. Arkansas doesn't have snow-capped peaks.
Good Night, Dear Heart - November 9, 1957 - S2-E17
Other mistake: Sam opens Hila's diary to a page. The translated voice-over mentions the 4th of July, America's independence and how she met someone with whom she could fall in love etc... The actual text on the pages mentions only the "Beginning of July" and how "3 bears and a zebra were born in the zoo. "Anton" was there and told her about it. His entire family was there and had a lot of fun." The right-hand page mentions how they had a wonderful day visiting the castle at Chiemsee where they had lunch. (00:21:02)
8 1/2 Months - November 15, 1955 - S3-E12
Other mistake: Towards the end of the episode when Sam is being wheeled into the delivery room in labor, there is a mirror above the table. We see Sam's reflection in it when we should see Billie's. (00:44:45)
The Right Hand of God - October 24, 1974 - S1-E4
Other mistake: In the locker room, the old man's hair is pulled down over his right eye, away from the mirror as his right side is toward the wall. In the reflection, his hair is facing toward the mirror over his left eye, rather than away over his right.
Glitter Rock - April 12, 1974 - S3-E17
Other mistake: During the album signing at the mall, a woman exposes her breasts to Sam. We see her from the front with Sam's hat covering her breasts. His hat moves just enough that you can tell she is wearing something covering her breasts.
Mirror Image - August 8, 1953 - S5-E22
Other mistake: At the very end of the episode, the last thing to show on the screen are the words "Dr. Sam Becket never returned home." They spelled Beckett wrong.
Answer: Sam threw items off the raft to lighten the load, so it wouldn't sink, in doing so he made the raft less heavy. Which made easier to float with the currents, if it was heavy the raft would have moved slower and not moved so far.
Except that Al said that immediately after throwing stuff out of the boat four hours passed and it was shown that they didn't really move from where they were. They were still in the same spot. Forgot to ask this too. When Sam and Vanessa are stranded on the island, one of them, can't remember who, did something and when Al appears, he tells them that because of it, time had suddenly skipped several more hours and if the event hadn't been interrupted, they would have been rescued by a boat. So, what happened on the island that once again caused time to speed up? It seems kind of strange that time could move so quickly on the island, especially since it was still day time and it never showed any sort of changes like the sun or clouds moving.