From the hut neat the lake to the summit of Mt. Cook it took me approximately 2.5 hours instead of 2 hours indicated in the book. That was mostly due to loosing the trail from where scree begins. It was difficult to find the next cairn standing in front of that huge and annoying scree field. I had to take my best guess where to proceed. When I ma finally done it and managed to scramble to the range I found there three huge cairns next to each other. That was an another confusion - it this the top? No, it was not. The real summit of the Mt. Cook was still a few hundred meters to the right with some additional elevation gain. Anyway, after approximately 2.5 hours (I began from the hut at 14:00 and reached the summit at 16:30) I finally was standing by the final cairn marking the top of the Mt. Cook. The view is fantastic from there to all directions. No water source on the top whatsoever, so bring your own. The way downhill was same confusing with finding the next cairn to follow. Passing that huge scree is very annoying since it is nothing, but loose rocks.