On another mystery...I saw a 2-hour show a while back on the History Channel about the guys who escaped from Alcatraz. It convinced me that the 2 brothers at least, probably survived, and I’m pretty hard to convince about these things. Check it out if you can find it.
I saw that show also, but my conclusion was different -— it seemed to me more likely that they missed their landfall and got washed thru the Golden Gate and out to sea by the strong outward tide.