Well, the boom on an Old Town lateen rig is usually held in place with a bronze jaw that is screwed to the boom as shown below. The screw heads are commonly covered with a twine wrap. See https://www.wcha.org/forums/index.php?threads/10672/ for some pictures. The halyard connects the yard (which is occasionally called the top boom since it is the same size as the bottom boom in a lateen rig) to the mast. This is frequently connected to a screw eye in the yard. I use a clove hitch around the yard if I want to retain the option to easily adjust the attachment point. Let me know if this doesn't answer you question or you want more details.
this is the setup I have , On the one here in the shop has a strip of leather holding the two booms together, like a hinge. I was thinking of #11 holding the lower boom to the mast. just a lashing or knot?
The "two booms" (i.e. bottom boom and top yard) are usually attached with two bronze eye bolts and an "S" hook. The picture at https://www.wcha.org/forums/index.php?attachments/24819/ shows the jaw above holding the boom to the mast. A lashing or knot at #11 is not commonly used. Let me know if this isn't clear,