This is actually a lofting.
These are the same oars that go with our wherries and double enders, like the 8-foot ones driving the Duck Trap Wherry in the photo. What makes them more efficient is that the inside of the blade is actually flay with the outermost 6" curved to hold more water. And with the convex side well rounded and faired into the loom, not only do they trail nicely, but chances of "catching a crab" are slim to none. Not only that, most find them far easier to make than straight bladed oars simply because those have to be identical on both sides. Think about that.
This is a single page plan depicting 7', 8', 9', and even 10' modified spoon oars. Here's the answer for anyone the least bit skeptical about scaling up oar dimensions from a plan and getting the details right, because it shows the swept blade, the elliptical loom, the all-important handle, and even the windings, all full size. And in the case of the 10-footers, it even shows you the best way to laminate the looms.
These days, when a pair of even straight bladed 8-footers from a well known manufacturer will set you back $400, you might want to seriously consider making your own. There is no mystery to it, particularly when you have a proven design and a full sized plan to guide you.
For those unaccustomed to windings, we use them in preference to leathers. There are no driven fastenings to weaken the oar at the fulcrum point, and they outlast oar leathers many times over. Here's what they look like...
This photo is from Building the Duck Trap Wherry.
This plan is complete and detailed, but if you are still not sure whether you can make your own oars, we do have further information available. It's in Lapstrake Boatbuilding, of course, as well as in the Matinicus Double Ender book (and CD) and others. It's even in the Maine Skiff book, and in all those you will find information on stock selection and the manner of layout and shaping the oars. Combine any of those with this full size plan and even the most hesitant should be good to go.
Fact is, with a some elbow grease and perseverance you can save hundreds of dollars making your own oars.