A few things to add to Ben's tutorial that Kelvin showed you.It's a good idea to minimize the number of profiles. You might even be able to get away with less than Ben used. More profiles tend to lead to kinky surfaces. Similarly, minimize the number of spline points. More points tend to lead to kinky splines. Ben didn't discuss tangencies, but you need to make the splines perpendicular to the center plane unless you want a kink at the center of the canoe. Similarly, the Loft (or Boundary Surface) needs to be perpendicular to the end profile at the middle of the canoe, assuming that you mirror it as Ben did.
You may want to use a Boundary Surface instead of a Loft. They tend to be more stable and well controlled. You might also want to Loft only to the last section before the end, then use a Fill Surface for the End.
You might want to use Guide Curves for a Loft, or curves running lengthwise for a Boundary Surface. You don't need to, but it might make more sense depending on what part of the shape you most want to control.