My original plan is 20 hours, the actual time is 20 hours and 51 minutes. We planned to start at 3:30AM Saturday morning, but checking the weather at Friday, the forecast suggested that there was a high possibility of snow shower and thunder after noon at North Rim with ~40 miles gust wind. So we changed the plan to start at 10:40PM Friday night.
The weather is near perfect from the south rim (south kaibab TH) to north rim, but I don't pay attention of the temps. I started with 2 layers (long shieve and wind stopper), took the wind stopper off at Phantom ranch, put it back on near north rim. The north rim is chilly, I only stayed there for 3 minutes because of the cold. I got back to Phantom ranch at 12:40PM, the temp is 90+ F. I took almost 1 hour break there just to stay away from the heat. In bright angel trail, near river is still hot when I started again, I hike with long shieve and short, need to put the wind breaker on again in Mile 1.5 rest house.
I am a person afraid of cold rather than heat, so I am very happy with the temp mother nature gave me this time.
Regarding the water,
1. South Kaibab to phantom ranch 0.5 liter. (~7 miles)
2. phantom ranch to cottonwood camp 0.75l. (~7 miles)
3. cottonwood to north rim back to Supai Tunnel (~9 miles) 2 liter.
4. Supai tunnel to cottonwood (~5 miles) 1 liter
5. cottonwood to phantom ranch (~7 miles) 1.5 liter
6. phantom ranch to indian garden (~5.5 miles) 1.5 liter.
7. indian garden to TH, don't pay attention since miles 3 & 1.5 provides the drinking water.
I carried more water than I needed in north kaibab since I didn't know whether the water is available or not in the trail. I always drink a lot during the break.
The main reason I didn't get this done by 20 hours are:
1. I almost twist my thigh when I descent from Supai tunnel, stop 10+ minutes to stretch and walk slow for next 30 minutes or so due to the pain.
2. the long break in phantom ranch due to heat.
After I started again, I know that unless I pushed very hard I won't complete it in 20 hours, not 100% certain about my thigh, I decided to take a easy pace, great views, friendly hiker along the trail, deers, blossoming cactus, it turns out to be the best hiking section.
I met a pair of R3 runner, they were targeting 11 hours! Other pair of frequent R3er, they started at 1:30AM, probably finished 20 minuets ahead of me. Unbeilable!
I am just glad that I completed the R3.