Was offshore this morning, caught a few kings.  I get slammed on a sardine and almost as fast as I could blink my eyes over 300 yds of 30# braid flew off my spinning reel, soron 70 with 30# of drag.  I cranked the drag as tight as it would go and still could not even slow this thing down. Finally my 60# leader snaps, it's gone.  Wasn't a sailfish or wahoo, it didn't surface, my reel would stop any king, too fast for a shark.  My guess a nuclear powered submarine.

How far off were you?  Sounds like a mako!  They are fast!  If fishing around an oil rig...Big AJ?  Could be a million things! LOL

129 feet of water, no oil rigs.  Amberjacks fight different, may have been a very large cobia, they are running now.

This cobia ran 61# and brought it in on a party boat with a fresh water spinning reel and rod, but I was 30 at the time, lol.

I've caught a BIG Wahoo (about 100lbs) that did not surface in Walker's Cay. So you can't count them out. 

You got schooled on a smoker king.  No doubt about it.

Sounds a lot like a big king, wahoo, or an AJ.  30 pounds of drag aint necessarily going to stop a large critter.  I've had my 80 wide trolling reels smoked by big kings and wahoo over in Bimini.  Could just as easily been a shark.  Thats one of the reasons why I still love saltwater fishing, you never know what may come along in the spread and start to nibble.