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.

Frame work and Im Memoriam

 After delays due to the "day job" last weekend, I finally got started building the frame for the main hull.  The suggested procedure involves transferring the frame cutout patterns from the full size plans to 3/4" particle board with carbon paper.  However, our experience with the floats was that it was difficult to accurately align the full size plans on the board.  So we have been transferring the plans to card stock (poster board) and then cutting out patterns that we can trace on to the particle board.  This allows us to very carefully align both the top edge and the vertical alignment marks.  In this case, rather than making 14 separate patterns, one for each frame, I transferred all of the patterns to one (large) piece of card stock.  Then I cut each pattern as I needed it, followed by reassembly with tape into a single set of patterns.  I will once again provide my highest recommendation for rotary cutters.  My rotary cutter was able to cut the stock in one pass, while easily maintaining good accuracy.  After 14 frames, you can see what is left of the patterns.  It actually worked quite well, and just required a little extra effort to carefully reassemble the patterns to assure no distortions are introduced.  I also transferred various other reference points (waterline, floors, etc.) from the plans to the patterns to the particle board.  I actually think it would be quite valuable for the plans to come with a set of full size patterns on card stock, or at least available as a premium add-on.

It took about six hours to transfer all of the patterns to the sheets of wood and trim the sheets to final size.  I am not sure if this is a lot of time or not, but 25 minutes per pattern seems reasonable given the need for accuracy and the number of steps involved.  I also marked the forms to provide space for fairing strips, as we did for the floats, which also required some time.  Here are the sheets cut to size and awaiting their turn with the jigsaw.

For fairing strips, I decided to try ripping some 3/4 ply into strips.  The solid wood strips tend to warp and twist, whereas the ply should remain true.  The solid wood fairing strips I purchased at the local hardware store also had some variation in thickness while the ply is very consistent and precise.  The ply costs a little more, and it will take some time to cut all of the strips, but I am hoping it will make for a truer form for the hull.

I cut the first frame yesterday (actually it was frame 8) with no problems.  Then I set up to cut out the next frame (frame 7) and after cutting about an inch, my nearly new Ryobi jigsaw died!  We bought it to cut the float frames, and found it a reasonable tool given the low price (although the laser guide was worthless since it couldn't be properly aligned with the blade).  I have generally been happy with my other Ryobi tools, and have not had any similar problems.  I haven't tried opening the jigsaw up yet to see if it is a simple fix (broken wire).  Looking online, I found many people had bad experiences with this saw.  I decided to get a better quality saw, under the (possibly misguided) assumption that a better saw won't suddenly die after so little effort.  After reading various reviews, I settled on the Bosch 1590EVSL which received highest recommendations from numerous professional and personal reviewers.  Unfortunately, I couldn't find this saw anywhere locally, so on to internet commerce.  I did find a very good price at Coastal Tools, hopefully they are quick shipping so we can finish cutting the frames next weekend.  In the meantime, I will try to get all of the other tasks out of the way, such as cutting fairing strips, transferring patterns for bulkheads, etc.