Gregg: The Penn International 16S is not a spinning reel; It's a 2-speed lever drag reel (your original question asked for info. on fly and spin).
Depends on what kind of sharks you are looking for. I wouldn't try to catch a large really large shark on a 16s, but might opt for a 20T, matched to the Penn International 1355 ARA stand-up rod. I have this set-up and like it alot. Works well on small blue and white marlin too. If you are really interested in using spinning gear, look at the shimano baitrunner 5500 or Penn 8500 & 9500. they're huge reels and can hold plenty of 30# mono. Matched to the Penn International 1140S orPower Stick PS-4821M, and you could do it with spinning gear.
For fly gear, try the big Penn 4.0 International, Orvis Odyssey, Billy Pate, Abel; any high-quality reel (reels *ARE* important when tackling big-game). I use the Penn 4.0 with a G.Loomis 14 weight and have used the Orvis Odyssey reels in the past.