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CS17 bottom stringers


Tgabe

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I am having a tough time with the bottom stringers just aft of the forward bulkhead.

With the curve of the hull, the taped seam where the two thicknesses of plywood meet and the curve of the filet on the bulkhead, I can't seem to get the stringers to lie flat.  Even after an hour of sanding, planing, and filing to try to get it shaped correctly.

Wondering what others have done.  Are there other options?

Thanks for any input.

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I'm assuming that the CS 17 Mk-1 is built the same as the Mk-3. Are these the full length bottom stringers? If so, they are glued to the bottom panel before it is folded up. If you mean the short bottom stiffeners that lie at an angle, they are oriented so they lay flat in the curve. They do not run straight fore and aft. Plywood always bends one direction, so that it is flat perpendicular to the bend.

 

If I misunderstand what you're asking, I'm sorry.

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Chick has it and I think he's talking about the diagonal bow reinforcement battens used in the mk1 model. If this is the case Batman, just move them around until the lie down. As Chick mentioned, plywood can only bend in one direction (okay, in theory), so by changing the angle a little, it find its happy place.

 

On my CS-17 build I elected to just reinforce the area with biax (no battens). I use a couple of layers of 12 ounce, covering the whole of the forward bulkhead area, from just above the chine and down. I considered this lighter and neater, than the battens.

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   Chick and Paul,

   Unless the plans have changed (and they may have) the stringers that Batman is talking about are installed parallel to the center line of the boat.  The straight stringers that are installed on a diagonal are forward of the forward bulkhead.  The ones Batman is having trouble with are aft of the forward bulkhead.

   Batman, I wish I could remember how I dealt with that part of the build but it's been too long.  I remember looking at it and thinking about it but I don't remember how I did it.  Most likely I scribed the curve onto a straight piece of lumber by cutting the straight piece to length and sitting it in place so it was only resting on its ends.  If you use a spacer or a compass that is set equal to the largest part of the gap you can scribe a line that tapers from cutting nothing in the middle of the piece to cutting a lot at each end.  The spacer follows the bottom of the boat so you'll automatically compensate for the bump where the thin forward panel meets the thicker bottom panel.  That might get you most of the way to a piece that fits but you may have to knock a little off here or there.  I wish I could remember if that's the way I actually did it.

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This is bringing back memories.  I used 5/4 douglas fir for mine, and cut the orientation of the grain so it would bend easier.  I used temporary drywall screws to hold them down as the epoxy putty set. Paul has the idea, skip them entirely and do a layup of a couple layers of 12 oz. biaxial cloth set in epoxy.  It will give you another inch of space under the forward seating area, and make it easier to keep clean, and also still serve to support the thinner ply at the bend of the hull.  

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Ken is correct. I am talking about the parallel bottom stringers.  So my options are:

Set them in at an angle - they seem to lay flatter that way. Scribe them to the shape of the hull. Or, order some 12 oz. biax.

The stringers forward of the bulkhead are already glued in. I would include pictures but I keep getting an error message when trying to attach.

I think I will order the biax cloth.  Thanks for everyones help.  Looking at everyone else's pictures keeps me motivated.

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I had to go back and pull the plans and some pictures, so now I remember the fore and aft stringers, which in my modified interior furnishings, would have been inside the forward buoyancy chambers. I thought of these as water catchers, so I used 2 layers of 12 ounce biax on the whole area, even using it as the tabbing for the a bulkhead, killing two birds with one set of tabs. I figured this box will be sealed up, except for a 6" deck plate in the seat top, so I didn't bother to do much weave filling or fairing at all inside these boxes. I tried to work neat inside the boxes, with clean edges and overlaps, but little else. In fact, I used a white pigment as the final neat epoxy coating, to make this chamber easier to find things in, if used for storage, because painting it again (at some point), through a 6" deck plate for the sole access, seemed unlikely.

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