the party travelled via darjeeling, kalimpong and kampa dzong and were blessed by the lama when they reached rongbuk monastery on 25 april 1936 in fine weather and good snow conditions on the ground. sixty porters had accompanied them from the start and another one hundred were recruited at rongbuk. by 9 may smythe, shipton and warren had reached the north col at using the same line as the 1935 reconnaissance. heavy snow that day and next delayed progress and destroyed the steps cut to the col itself so a fresh attempt was made on 13 may, led by smythe. smythe had been asked to save his energies for the summit by not cutting steps himself so he appointed sherpa rinzing to lead. this was the first time a sherpa had led on an everest climb. fixed ropes had been installed to camp iv at the top of the col in five days whereas in 1933 it had taken fourteen. over the next two days camp iv was established using 96 carries by porters, leaving thirty-six at the col from where smythe and shipton were poised to establish the camps towards the summit. for the first time the climbers were able to use portable radios – the ones of "extreme lightness" weighed only .