As you can see I have now rolled the frame over and used plastic 6 gallon buckets to raise it off the floor. I have positioned the coupler in preparation to weld it in place. The  ½" round stock which strenghtens the side rails has been added.  Also, my axle has arrived so I am ready to position it under the frame so the spring hanger brackets can be welded in place. 

It was at this point that I encountered a problem.  I had built the frame according to plans and used the configuration for a V bottom boat.  The main difference is that the cross supports are not straight but shaped in a "V" to accommodate the hull. 

As per plans, the springs are attached to two (one on each side) lengths of 2½" x  2½" x ¼ angle iron.  These ride beneath the frame and create an undercarriage that can slide the axle back and forth to adjust the amount of weight on the tongue (60 to 65 LB suggested).  But I encountered a problem when dry fitting in place.  Because of the cross member drop down the angle iron hit the cross member and was prevented from mating flat to the bottom of the frame side rail. You can see the problem in the photo (view looking up from below the frame).  The arrow actually on the cross member and pointing at the place the angle iron is hitting it.

This obviously was not going to work.  If I had realized that this was going to be a problem I would have been more careful in positioning the cross members.  I could have cut them so they were sitting a little higher and most likely provided the needed clearance.  But as the say, hindsight is 20/20. 

Repositioning the cross members at this point was out of the question.  The only solution that seemed to make sense was to "lower" the angle iron.  The way I decided to do this was to weld ¼" spacers on the inside of the angle iron.  I positioned five of these along the bottom and reasoned that the best location was under the five bolt holes I had punched* in the angle for the bolts to attach it to the frame. Also, two of the holes and spacers were stationed directly over the spring hanger brackets to eliminate any twisting  to the angle that could result if it were unsupported. 

The photo here shows one of the spacers in place with the bracket under it and the bolt hole over.  This solved the problem and the undercarriage can now slide along the frame as per plans.

With this done I was ready to position the axle assembly under the frame . I wanted the tires and wheels attached so I could determine where the fenders need to placed.  To establish the height clearance I measured the space between the frame and the axle.  It revealed that the total travel of the spring was 3" before it hit the frame solid.  I decided to set the fender 4" above the tire.  Once the height was set the fenders were centered and then angle iron supports were welded to the side of the frame.

I had also decided I wanted a step both in front and behind  fenders.  This would be handy when accessing the boat on the trailer and also added extra beef to the fender mount.  The photo shows the front step welded to the angle iron.  Be sure you cut the angle iron undercarriage rails long enough to accommodate this if it is an option you decide to incorporate.
 

* I was at my friends machine shop getting the 2½" angle I needed and I was cutting it in a sheer that will handle up to 12" x 12" x 1" thick angle !!!!!  In the process I  noticed that there was a hole "punch" designed in to this machine and it was set up for 7/16" holes. I slid the ¼" thick angle into it and punched the 10 holes in less than a minute! It would have taken longer than that just to get it setup in my drill press and than I would have to drill the holes.  Having the right tools sure can make a job easy!