Are you saying that you cannot do 2000 yards non-stop in a pool? If that is so, I think you have a problem, and I think you should slow down your pace and stop the damn 5 second rests.
I “learned” to swim last year, and did a half without a wetsuit, and 2 IM’s with.
Be sure to do some warming up just before the swim in the water, and then be super careful not to go out too fast, or the next thing you know you will be gasping, your heart will be racing, your eyes will be bugging out of your head and you will be panicked and looking for a kayak. Let everybody go. You will catch them later. Actually, you will probably not catch them later, but it is a good thought to hold.
If you do get spooked, just try to go back to the slowest swimming-like thing you can do, take big breaths, be sure to exhale (under water, just as you would ordinarily), and trust that it will straighten itself out, just like it does if you go out running too hard, but it will take a minute or two. But be sure to exhale, don’t just keep trying to pack air in on top.
I’m saying I don’t know if I can do 1x2000scy. That would 1) take forever, 2) be boring as hell, 3) I’d lose count anyway, and 4) I’d probably cheat eventually and stop even if I could go on under pressure because that wall is so damn sexy to hang on to after >10 laps.
Yesterday I did a slow 10x100 on 5 secs rest. It was easy from a work standpoint, and I never felt tired anywhere other than the rear of the shoulders. My bad shoulder hurts a little now (that’s why my yardage in workouts is always so low, and I can’t just throw volume at my swim woes to improve). Not sure whether it’s speed (or rather force from harder pulls) or distance that bugs the shoulder. If it’s speed, then I’m in luck!
If I make the swim cutoff anything less than exhausted, I’ll catch plenty of folks throughout the bike/run. No question there.
I think I’d start on the beach, and just cruise at the back. Being last out would really really hurt mentally, though. I’ll be the fastest-looking slow guy for sure.