Setting up the main hull frames

 The new Bosch 1590EVSL jigsaw arrived on Friday, and I immediately got back to cutting out the frames for the main hull.  After several hours of use, I highly recommend this jigsaw.  It is easy to control, and maintains the blade at the intended angle (perpendicular to the surface in this case) extremely well.  I was able to cut the remaining 13 frames in about three hours.  Then I started aligning the frames on the strong back.  Here is a photo of the first frame (actually Frame 14) being set up and aligned.  I used several methods to check and compare elevation, plumb, and level.  The primary reference was the laser level, seen in the foreground, which projects both a level and a plumb line.  With a little effort, I was able to set the level line to the elevation of the top of the frames and the plumb line to the string line that runs the length of the strong back.  Working from the far end forward allowed all frames to be set to the same references defined by the laser.  Although not technically necessary, the laser level greatly improved the overall alignment of all the frames and also made the process easier.

 Here is a view of Frame 10 fully "instrumented" for alignment.  I have the laser lines discussed earlier (hard to see due to bright daylight), a level across the top of the frame, a plumb bob hanging on the alignment reference line, and the string line reference along the bottom.  I used shims to adjust elevation and level, as seen at the bottom between the strong back and frame.  Once all measurements agreed and I was satisfied with the placement, I added a couple more clamps to fix the frame in place and then screwed it to the strong back.  I will go back later and set the frames plumb fore and aft, and set the spacing at the top of the frames to match the bottom.  I only needed the frames to be close to plumb fore and aft to set the elevation and side-to-side alignment.

 A few hours later, and all of the frames are aligned (nearly perfectly I am happy to say).  In this view, the laser cross is easily seen on Frame 1.  The frame is mostly cut out except for two small sections which I will cut later so I can more easily align the frame.  I made a shallow cut at the top of each alignment reference line to make it easier to set the plumb bob.  With the lights off, the laser is visible through the alignment cuts in the entire set of frames simultaneously.  And the top half of the horizontal laser line is visible at the back wall.  Hopefully this will result in a very true hull when I go to put the two halves together.

And here is the view from the aft end.  You may notice that all of the frames have beams across the top.  I left these pieces on the frames so I could more precisely align the frames.  Once I get all of the frames plumbed fore and aft, and tied together with correct spacing, I will go back and complete the cuts to remove these beams.  I plan to keep the off cuts so I can temporarily reattach them when I reverse the frames for the starboard half of the hull.  The beams also help reinforce the larger frames until they are attached to the strong back and tied together.  Although it took a little extra time to layout and cut the frames like this, I think it greatly improved accuracy of the alignment.