Bad situation. I thought last night that they're probably dead.
Though they supposedly have some experience and I don't know if I have the story but it sounds like they were headed over to the Bahamas without telling their parents who probably would have stopped them.
From Miami/Fort Laud it's only about 50 miles to Bimini but from Jupiter it's closer to 100 probably, looking at map, yeah, about 70 to the nearest point but it's not even so much distance as it is conditions.
Even if it looks real flat when you head out, that Gulf Stream can act up seriously and quickly. In south Florida you can sometimes see from shore how the water level rises out there. It'd be especially nasty if a summer thunder storm came through as they were crossing the stream and it put out some southern winds running counter current. A little boat like that could get tossed.
These kids though, I've seen some vids of them running out there on waverunners with gas cans strapped. Me and my friends were pretty nuts but we didn't even do that shit. The last smallest boat I was on to Bimini was a 60 something footer and usually under 40 you try to go with a buddy boat to be safe.
Maybe I'd take a 40ft cigarette out there quickly on a flat day without a buddy boat, but with radar and range to get around a storm. But a little 19 footer single outboard engine? No. That's for boat people escaping Haiti as a last resort, not for neighbors of Joe Namath living life as a resort.