In biblical times, when was it unlawful to tie or loosen the camel-driver's knot and the sailor's knot?
Here's answer to week's question Under the lengthened rules decreed by the scribes pertaining to the Law of Moses, certain kinds of knots might be tied on the Sabbath. The camel-driver's knot and the sailor's knot were among those that were unlawful on the Sabbath; it was equally unlawful to tie or to loosen these knots on this day. A knot that could be untied with one hand could be undone lawfully.
Source: James E. Talmage, Jesus the Christ, (1981 ed.) p. 215.