“How did the great Elon Musk propose they get his sub over the several sections above the waterline?”
He got it to Thailand!
Elon and yourself seem to be under the impression that this was still water all the way to the entrance. This is incorrect. If it was that easy, an experienced diver wouldn’t have needed to take 6 hours to get to the boys, and wouldn’t have died running out of air trying to get back out; airpockets were few and far between.
About 20% of the rescue time was actual swimming. In about 80% of the cave “full climbing gear” was necessary to scale dry rock to get around to the next section of water. The boys were strapped onto stretchers for each climb and hauled up by the divers/climbers. The ‘muskbug’ would only have been effective for the first 100 ft dive to Pataya Beach and then it would have been stuck, unable to proceed and in the way, turning it into a hazard.
simplified crosssection of cave, showing high and low spots and underwater dead-man traps:
https://wdef.com/wp-content/uploads/2018/07/ctm-0704-thailand-cave-rescue-map-5-1.jpg
50 sec. video showing narrow passages and underground current:
