A Yew shortbow (u) is an unstrung shortbow made by using a knife with a yew log. It requires a level of 65 Fletching to create it giving 67.5 Fletching experience. A bowstring is needed to complete the bow. Once the bow has been completed you will receive another 67.5 Fletching experience, which is a total of 135 Fletching experience. It is more profitable to cast high alchemy on Yew shortbow rather than Yew shortbow (u)'s due to the difference in coins received.
It takes 15 seconds to string an inventory of 14 shortbows. With banking time, this means players can potentially string 3 inventories a minute, which is 180 inventories an hour, for 2,520 bows in total. This means that the experience gained per hour is roughly 170,100 Fletching experience.