I just had to go through the same thing a few months ago with a friends galvanized boat trailer. The tongue was a single 2" x 3" x .095 wall thickness rectangular tube. 8-feet before it came to any bracing. The trailer came off the ball, and buckled the rectangular tube, and coupler. I inserted into the rectangular tube 10-feet of 2" x 2" solid square stock, and plug welded it to the tube, along with a new section of tube, and a new coupler.