I've bought the material to make my oars with and have deterimined that the oars need to be 7'-6" longs as per a forumla that Don posted earlier. Now I ain't using no plans to make these with, just my noggin. The blades will be 7-14" wide and 3/4" thick. Yes I'm using dimensional lumber. My question is this. I laid out the blade to be 20" long and than it starts to taper down to the handle. It takes about 6" to do this. Looking at it laid out this don't seem long enough. What should the blade length be?