The only way to know for sure is by getting the correct shell fit (the sticky at the top of the page has pretty decent guidelines to go by).
Typically, a 29/29.5/11US shell is for a 12 foot and Salomon does not make a larger shell size. So if you are truly a 13 foot (which quite often people are wrong about their foot size) you might be out of luck. But like I said, the only way to know for sure is to get shell fit.