Scott writes as follows:
This we commandeered as a yard for a floorcloth sail. I imagine it was intended to mark the exact spot of the Pole as near as the Norwegians could fix it.
Later on he remarks (among many references to drawing sail on his return journey):
At first with full sail we went along at a great rate; then we got on to an extraordinary surface, the drifting snow lying in heaps; it clung to the ski which could only be pushed along with an effort.
Amundsen also writes (multiple times) about using the wind:
Wisting now used a sail on his sledge, and was thus able to keep up with Hanssen.