Sentence:  Every piece of binding is first carefully examined and tested; then it is put on, cautiously and accurately. Every turn is hauled <WSD>taut</WSD>, taking care that it is in its right place. [...] A sledge journey of the kind we had before us is a serious undertaking, and the work has to be done seriously. 
Meaning of the word marked with <WSD> tags:  Under tension, like a stretched bowstring, rope, or sail; tight.