Some photos of gaff rigged tacking outriggers from Tahiti. Note the strong forward crossbeam and the flexible aft crossbeam. The top line diagram was drawn by Ovlind Gulbrandsen
in 1984. The sprit and gaff rigs were introduced to the pacific by Europeans, these rigs being used on the small boats of their smaller boats.
Note some of the older boats have a spar extending from the stern, I believe this is called a bimikin (pls email me if this is not right). The bimikin is used to control the sails, my rough guess the line goes to the lower spar on the gaff rig? Or when combines with the sprit rig, the line appears to connect with the top of the sprit