Tuesday, August 16, 2011

Week 2 - Framing the frames, Chines & Assembly

Week 2 started with adding the brace framing to the bulkhead panels.  Much care and careful reading of the instructions were necessary to make sure I put the sticks on the correct side of the panel.  The instructions describe the procedure with some drawing references in one section, and the detailed diagrams with dimensions are in another section.  So there was plenty of flipping back and forth trying to confirm what was what.  The panel assembly set the stage for most of the build.
     1. Measure carefully and cut parts to size
     2. Dry fit and screw pieces together with dry wall screws and packing-tape covered pads of scrap plywood
     3. Take it apart, add thickened epoxy
     4. Re-assemble the part and wait for the epoxy to cure

 Here is frame 3 all glued up.  Notice the plywood pads that protect the panel surface from the screw heads.  The packing tape keeps the pads from becoming unintended permanent structure.  I followed other builders advise and pre-finished the plywood panels to some extent before adding the framing structure.  The panels are a lot easier to sand when they are flat, without all the nooks and crannies created by the added framing.
Here is frame 4 in the foreground, with frame 2, I think, behind it.  Like I said up above, the hardest part is figuring out which side of the panel the side bracing, seat cleats, or bottom cleats are supposed to be on.  Some panels, like those above, have parts that are added on later, after major assembly.

Here is a picture of the framing of the transom panel.  Unlike the rest of the panels, I followed Mike Storers advice and used weights and clamps on this glue-up instead of the screws and plywood pads.  Not putting screws through the transom plywood preserves the option of finishing the transom naturally without any unsightly blemishes from filled screw holes.  Will I finish the transom bright?  That is the plan for now.  At least until my wood butchery skills force me to paint it instead.

Along with the framing panels, I also was working on prepping the bottom panels.  Diverging from the plans, I made the bottom panels from 9MM plywood instead of 6MM.  To me, it was worth the additional weight to have the peace of mind of a little more material between me and the briny deep.  This boat is not going to be a museum piece and may see some hard use.  For that reason, I also decided to diverge from the plans a bit and glassed the inside of the bottom panels with 4oz fiberglass cloth to provide added protection from dropped items and moving about the boat.

Here is one of the bottom panels after being glassed and wetted out with epoxy.  Notice the centerline and framing positions are marked with a sharpie.  After wetting out, the glass cloth goes clear and the sharpie is clearly visible.  This was great for assembly.  Just be sure that you don't intend to finish these panels naturally, otherwise everyone will get to see your assembly markings.  Might make for interesting discussion when the wind deserts you, but I'm just going to paint over these panels.

Next, I scarfed together the Chine stringers from clear vertical grain douglas fir.  The plans call for cedar.  I decided on douglas fir for some additional strength.  The scarf joint was set up as 10:1.  I rough cut the scarfs with a circular saw and finished them with my grandfather's No. 7 Bailey bench plane.  And just like that, I turned four 10 foot lengths of douglas fir into two 19 foot lengths.  After gluing the side panels together with butt-block joints, I dryfitted then glued the chine stringers to the side panels.

Here is a picture of the dry fitting of the chine stringer to a side panel.

The stem piece was laminated up from a couple pieces of douglas fir.  The stem on the Goat Island Skiff is triangular and tapers from one end to the other.  As a side note, working on a triangular piece is a pain in the butt.  There is really no conventional way to hold the piece secure to final shape it.
With the stem completed, it was time to mate up the stem to the side panels and turn this thing into something that resembles a boat.  One beautiful aspect of the GIS design is that there is no mould or strongback structure that you have to build to support the structure during the build.  Just build the parts and screw them together with some glue in the joint.  Let it cure, then pull out the screws.  I'm oversimplifying, but you get the idea.  Without a strongback structure, we come to a more critical operation in the boat construction.  Attaching the stem between the side panels should be done carefully.  There is very little surface area and the the parts set up the alignment down the whole length of the boat.  My advice, use at least two people, take your time, and use plenty of screws.
Here is the stem after dry fitting to the side panels.

After dry fitting the stem, I added frame three.

Next was the transom.  With the transom, it took three people.  One was mostly moral support, if you consider laughing at our feeble attempts as moral support.  In the end, we used a couple tie-down straps, some wood blocking and a lot of patience to pull in the ends and carefully align the transom and screw it all together.
Wha-la!  This is starting to look like a boat.  Here is what things look like after dry fitting including frames 4 near the transom and frame 2 near the bow.  What's next?  You guessed it, take it all apart, butter up the joins with thickened epoxy and try to put it all back together again.  Only now there is time pressure and everything is slippery.  But no problem, right, you've done it all before....once!
Here is the boat after the glue-up.  Time to take a moment to enjoy the fruits of thy labour.  That is my son Joe (the main helper, not the moral support one) giving his best impression of rowing the new boat.  I think he is too far forward and needs to move to the other side of Frame 3.  But Dads tend to be over critical.  A couple of things to note in the picture, the white notebook in the foreground is the plans and instructions that I downloaded and printed from Mike Storer.  That's 78 pages of instructions and 10 pages of construction diagrams.  Also if you look closely at frame 3, just in front of Joe, there are a couple of clamps on either side of the centerline.  My brilliant idea was to remove a section of the frame 3 seat cleat to make room for the centerboard case.  It would have to happen eventually.  What I failed to notice is that without the full length of that cleat, frame 3 is under enough tension to pull the ends into a bowed shape.  To straighten out the frame, I clamped another piece of wood across the gap.  There the clamps will remain until it is time to fit in the centerboard case.  Another lesson learned about thinking ahead.

So that brings us to the centerboard case.
Here is the dry fit of most of the centerboard case framing.  I will wait until I have the final dimensions of my dagger board before finishing the assembly.  The side clearance of the dagger board foil within the case is pretty critical.

That is about it for week 2 of the build.  At this point, I think I'm behind schedule by a day or two.  I had planned to have the bottom panels on by now.  Maybe I can catch up by next weekend.  Stay tuned!

1 comment:

  1. Thank you VERY much for the following observation: "...without the full length of that cleat, frame 3 is under enough tension to pull the ends into a bowed shape." I have looked at my #3 bulkhead more than one time with the thought of chopping out that section of frame. Now I see that would be a bad idea. You have helped another Goater!