I don't know what the weather will be like.
I don't know what the surf will be like.
I don't know how I'll be feeling.
I don't know how my stomach will react after over 9 hours on course.
I do know that unexpected things will happen on the course, and I will deal with them as they occur.
But that said, I can make some educated time estimates of my various performance scenarios.
Swim 2.4 miles:
A dream day: less than 1:38 (less than double my Steelhead swim time)
A happy day: 1:38 - 1:52 (faster than my Chesapeakeman swim time)
An okay day: 1:53 - 2:19 (staying just ahead of the 2:20 swim cutoff, possibly with swim problems)
T1 - Swim to bike transition:
A dream day: less than 0:08:00 (faster than Chesapeakeman)
A happy day: 0:0800 - 0:12:00 (Typical T1 for me)
An okay day: 0:12:00 - 0:15:00 (slower than even the Chesapeakeman chatfest)
Bike 112 miles:
A dream day: less than 6:45 = 16.6 mph (14 minutes faster than Chesapeakeman)
A happy day: 6:45 - 7:10 = 15.6 mph (right around the time of Chesapeakeman)
An okay day: 7:10 - 8:00 = 14.0 mph (staying ahead of the 10:15 elapsed time cutoff, perhaps with flats or other problems?)
T2 - Bike to run transition:
A dream day: less than 0:03:00 (faster than Eagleman)
A happy day: 0:03:00 - 0:05:00 (typical T2 for me)
An okay day: 0:05:00 - 0:10:00 (slower if I'm getting really, really tired; or doing very well and taking my time accessorizing for the run)
Run 26.2 miles:
A dream day: less than 5:52 = 13:26 min/mile (a marathon PR)
A happy day: 5:52 to 6:37 = 15:09 min/mile (faster than my tired Goofy marathon last January)
An okay day: 6:37 to 7:16 = 16:38 min/mile (faster than my slowest, hottest standalone marathon in Maui, 2001)
What would those times yield?
A dream day: 14:26
A happy day: 15:56 (pretty close to my best bet)
A not-so-okay day: 18:00 - which would put me over the finish line an hour after the cutoffs. Therefore I can't have problems in every discipline - I'd have to pull it out on the run and go fast (for me)!!! Which I could do, maybe, if I weren't exhausted! But this is a good reminder that nothing is certain in Ironman, and a big fat DNF is still a distinct possibility!