Here's a link to the history of rope making--with a point being made about the length of the rope being determined by the level of machines available during any historical period. When there weren't machines to aid in rope production and rope making was limited to hand twisting and braiding, the ropes were short and of limited use in seafaring. The writer on the site points out that even when ropes could be spliced [before the time of rope-making machines], the rope was twice as thick at the splice point and couldn't be used effectively for shipping.

http://www.rope-maker.com/ropehistory.html