I'm attaching the channels to the Discovery1789. Steel says that there are iron tees under the channels to reinforce them. Ships Repository says wooden knees on the top. When I look at the drawings in Mondfeld he shows both tees and knees. The drawings I have don't show either. I'm thinking that Mondfeld showed both just as a convenience for the book but I'm not sure. I've already installed the tees but I'm unsure of whether to install the knees also. I'm assuming that the iron tees superseded the wooden knees. Any help would be appreciated