convex vee

i have seen a rib with a gentle convex vee. apart from being stronger, what other benefit would it be? it runs out to a deep vee at the bow.

 

In general, most boats built out of 'plate' - be it aluminium, plywood or whatever, have convex sections in the bow. It is primarily a function of the material being used. When you bend a flat sheet around to fit the bow shape, it naturally forms a convex section.
You are correct though - convex sections are also stronger and have been shown to provide slightly lower resistance figures too. They tend to have more buoyancy in the bow sections so are less prone to digging in and bow steering too