Does a greenland paddle need a "shoulder" where the shaft meets the blade, or not? My knowledge of engineering is just about zero, but it seems there would be a concentration of stress where the two meet. Would a shoulder help by strengthening this point, or would a smooth transition from the shaft to the blade do a better job?

Below is a link to an article that provides a detailed drawing of a how a shoulder is made (see Step 4 in the diagram). An equally convincing article says there is no need for a shoulder. Any thoughts?