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NE Dory - stitch fitup before gluing
First-time builder here. Questions on fitup for those with more experience: are small gaps (1/16th inch or less) at the bow and bulkhead joints acceptable? They seem like things I can correct with epoxy+filler and sanding/planing, but maybe it's worth it to unstitch and restitch the whole thing to try to even things out. Every other joint is tight!
The bulkhead issue is only on the sbtd side of the No. 3 bulkhead - the lowest hull plank is inside edge-to-inside edge with the hull bottom, and the other hull planks are all tightly seated in the lap rabbets, so I don't know where I'd find any play to even the top plank out.
4 replies:
RE: NE Dory - stitch fitup before gluing
I've built a NE Dory. Based on the pictures, your bow stitch-up is plenty tight enough. In building several boats, I've learned to pay special attention to beveling planks where they will meet, even if not specifically called for in the instructions. This can help keep the outside/visible part of the panel joint edge-to-edge very tight, giving a very fine line between the panels. And wherever things need to be rounded over, minizes the esposure of underlaying laminate layers of the plywood. I make these notes because if you are planning to finish the exterior of your hull as bright (clear finish/wood), from what I see in the picture you will have a fairly evident amount of filet epoxy and plywood endgrain/laminates visible. Also, just as a hint (again if finishing bright) you'll want to try to avoid sanding through that "tab" of material right where the lapstrakes start to overlap - try to avoid showing underlayers of the plywood. All this is absolutely not an issue if painting.
I would look things over and do all the stitch loosening/wiggling/tightening tricks to see if you can get that the frame (as pictured) moved a bit so that it is no longer "proud" of the top plank, while still keeping your plank joints tight. Be sure you don't have any little tabs remaining on the edge of the frame, and that the "steps" of the frame are lined up and dropping into the overlap steps between planks - thus alowing each plank to have full contact with the edge of the frame - no gap or light betweene planks and frame. If anything is keeping the planks from full tight contact with the frame that might be why the frame tip is too high. The only reasong for the effort is to try to keep the hull as symetrical as possible. And if you spend a bit of time doing this but nothing improves - no big deal, tighten everything down and glue her up! In the end, focus more on the plank-to-plank joint tightness, and if that means the frame tip is still proud, you can sand the top off the frame and no one but you will ever know.
Consider CA glue for the "tack welds" if you haven't already. I did my NE Dory with epoxy, but I've since become a CA convert. I think CA tacks are much quicker and easier than epoxy, and no inadvertent drips or blobs to clean up/spatula away during the tacking or sand away afterwards. And much easier to make nice smooth filets afterwards due to not having to worry about your filet tool "feeling" the lumps af tack weld material as you pass over them. Even so, in some areas of high stress or larger gaps you might need a few epoxy tacks.
RE: NE Dory - stitch fitup before gluing
Bubblehead is spot on. One thing I'd add is to make sure there is no twist to the boat. Laguna has a good discription of how to use winding sticks here. On my dory I used two drywall squares.
From the pictures it looks like one side may be lower than the other at one or more bulkheads. This might induce some twist. Of course you want to check the bottom panel as well as top edge of uppermost strake.
Cheers,
e
RE: NE Dory - stitch fitup before gluing
Just wanted to say thanks for the replies - did a bit more stitching, checked twist, and she's glued up and ready for fillets and inner glass now.
RE: NE Dory - stitch fitup before gluing
» Submitted by spclark - Sun, 3/19/23 » 11:21 AM
In conversations I had with a CLC designer with a few years back he allowed that, with stitch'n'glue, "... 1/8" gaps are acceptable."
Being a first-timer myself I welcomed the inputs he provided in answer to my queries. For yourself, being also a firster, you may have tightened some stitches prematurely, resulting in the gaps your pics reveal. Easy to do with the excitement that comes with seeing your pile of flat parts turning into a BOAT as you progress!
Rather than start over, I suggest you maybe back off some of the stitches you have tight now, try to flex parts into a more gap-free alignment before retightening them. Assembly at this point is "a little here, a little there" until things are looking proper.
Too, don't be afraid to drill more stitch holes where you think they'd be helpful. Add stitches the factory didn't find entirely necessary when developing the kit parts. I had to take this approach in my build to get things where I thought they should be before starting the tacking process.
18 ga wire is 0.040" / 1.024mm dia. You'll need to find a source for number drills, #58, 59 or 60 will work (0.0420", 0,0410", 0.040" dia. respectively) and a 'pin vise' to hold it 'cause they're so small they won't work in standard 3-jaw Jacobsen-type drill chuck. I found a welding tip cleaning tool for a few $$ at a local hardware store that serves as a chuck and comes with a supply of very tiny drills, one of which was exactly the right size for this.