MASS START!!!! Great Floridian

If you truly have water panic issues, then start off to the side.  AWAY from the buoy line.  Yes, you will swim longer but you won't panic.  You slowly angle towards the farthest turn buoy. 

Also, when you swim in the pool, get in with someone in the same lane.  So many people avoid sharing a lane at all costs, this won't help.  It requires you to know where other swimmers are and you'll 'engage' them from time to time.  Like their wake rolling over you as you try to breath.  Simple things to do.

First off, not to worry...tight now there are 188 people signed up......not that big a crowd...if this still bothers you start off to the side where the crowd will be thinner......

And over the next couple of weeks, get some buddies to come to the pool and try to start from the end together with 3-4 folks in a lane....you'll get the idea of how to sort things out....

Paul 

Do the math like I did for IMLP.

Check times from last year's race.  See where you are relatively. I saw at IMLP I'd be off the back rather quickly so I just started in the back and swam. Realitiy was by 1/2 way to first turn bouy folks were spread apart and I was in back with my fellow BOPers. Honestly swim start at sprints with folks that can't swim or swim straight or swim and stop I have found much worse and I get smacked around more with those types of folks rather than serious IM people.

You'll have fun!

I like swimming and consider myself a pretty good swimmer, as far as triathlons go   I remember finding out IMFL was a mass start (WHO KNEW????) and feeling a bit of a panic     On race day, I figured there will be chaos and people will swim over me no matter where I start, so might as well start at the front...worked for me.  At one point during my Ironman swim, I popped my head up and giggled at the hilarity of it all. 

You'll be fine.