Check out this video from Jamestown Distributors on Steam Bending Planks, Inwales and Outwales. It's a simple way of doing it. Finding the materials may be the tougher task.
Louis is a rock star. I have watched most of his videos. The one about steam bending in a bag is my favorite although I don't see how it would work with a scarf joint in it but a great/simple idea. The one about indexing old screw holes is really cool also.
Mike: While never having to steam bend an inwale or outwale with scarfs( my local 1 man sawmill provides really long WO or DF stock) I have done several laminated curved stems and transoms. Jason Cajune and Tracy Obrien's designs call for curved stems. I made a form to fit the curvature, steamed the laminations- not glued yet- after they dried out they were about the correct shape. Steaming seems to "fuzz" up the surfaces and makes a good epoxy joint. Could you cut the scarf for the joint, steam the whole thing with Louis bag method and then clamp the sections to the boat and let it dry. They may not be a perfect fit but much better than done without steaming. Then epoxy the scarf on the boat. Someone try it and let us know if it works.
That is just what Brad Dimock did on his Kiwi build. I have been clamping the scarfed section to the boat and then steaming the front and back sections separately. I use a pvc tube and just pull the whole tube off of the gunnel and bend away. Works awesome and so much more pleasurable than trying to bend dry wood.
There's no reason this wouldn't work, steaming the ready to scarf pieces in the plastic bags will work. Just a little more work clamping them up when hot.
The scarf and attachment to the hull can be done all at once with the epoxy. I have done something like this with laminated stems on my canoes.
I'd like to hear also from someone who actually tried your idea.
Mike, I too am a fan of Louis.