In engineering, doesn’t Sigma represent an unknown quantity? 
Indeed. Here’s an aerial view from '63.
In full screen HD, the crossbar looks to me like it belongs to the pole with the flag.
Can anyone tell if it’s even a U.S. flag?
If it’s in compliance with the Marine Flag Guide, then it’s not “defiantly” at half-mast. 
Just to be kind to the OP, I DO remember the Gilligan’s Island ‘boat in a storm’ footage being used again - in a 1974 TV movie called Hurricane. I remember seeing it at the time (I was ten or so and an avid Gilligan’s Island watcher) and thinking ‘hey - that’s the Minnow from Gilligan’s Island!’
From watching this video, is there an eighth person inside the boat?
I count three in the bow, two in the stern, two on top the boat & one inside the boat.
What ever happened to the eighth person?
Uh… heh. That’s funny. Everyone’s fussing over a foot this way or that on the flag and misses this elephant in the room.
The Howells and the Professor (who would be the first actor, not Russell Johnson) are on the bow, the Skipper and Gilligan are up top, and the girls (one of whom would be the other replaced actor) are in the stern.
Reality: the real pilot is in the cabin and no one thought anyone would notice or care.
Continuity: This was the DEA agent they threw overboard so the Howells could complete their drug deal?
Speargun accident.
Harbor pilot? 
The bellhop stole him.
That’s why they couldn’t go back to the mainland right away. There’d be too many questions.
Besides, what else could they eat? Pineapples and bananas? They needed protein too.
Have fun storming the castle!
Seriously, everyone understood the question, we’re just having a little fun, admittedly at your expense. Give us another chance, huh?
Too late. The cat’s out of the bag. This firecracker has just been lit.
What seemingly started as a simple inquiry into flags and film clips has evolved into a full-blown conspiracy.
“Five passengers that sailed that day?” Clearly, there were six. Even in the intro for the show’s later years, EIGHT people depart. SEVEN land on the island. Yet no one talks about this.
This is bigger than the grassy knoll, or thermite in the twin towers. It’s on par with Chuck disappearing from Happy Days.
No, your obvious smokescreen to have us look elsewhere ALMOST worked. Now we’re onto the bigger picture, taking us further down the rabbit’s hole.
And you just may have gotten away with this, too . . . if it wasn’t for us meddling kids!
Not only that, but “set sail that day?” It wasn’t even a sailboat.
They had plenty of… (wait for it)…
Ginger.
“Kessel.” Get it right.
Final proof of the drug-deal interpretation, IMVHO.
More than one dictionary defines the phrase as “to begin a trip on a boat or ship.” Now go dial your phone.
I still want to know what difference it makes if the flag was at half staff - or not - on the day it was filmed.
WHile it’s an interesting question “was it” - I still want to know why I give a crap if it was or wan’t.
It’s just a guy in a suit!
The entire point of the trivium is that these sequences were filmed in the days right after the JFK assassination, which is not debated. The half-mast/-staff/-assed flag is apparently evidence of the timing, and mildly interesting for that reason.
Or maybe it’s really at half-mast because of a harbor pilot “lost at sea” that day… :eek:
ok - seemed that the OP was saying “and this meant x conspiracy” - thanks.
thanks