resizing/stretching a stitch and glue design

[KnottyBuoyz]

Originally Posted by tom28571

Not sure I understand what you mean but there are no frames in a typical S&G hull.

Maybe I should have used the term "Stations". Mine is built on a strongback on stations something like this.....



Yeah of course it would have helped to know which boat and the size you were building.

Just splice in the extra 10% at the widest part. Let the plywood define the shape of the hull and fix any gaps with goop & glass. 10% on a 16' boat won't make that much difference (19").

[ancient kayaker]

Originally Posted by tom28571

... Does anyone know a simple way to make this expansion without relying on a computer solution?

There isn't one, see post #4.

Originally Posted by KnottyBuoyz

Duplicate the widest frame and put it in at the same spacing as the original frame. Stretch all the panels to match the stretched portion. Some sanding and fairing might be required to get a nice fit.

That adds a cylindrical section midships; it assumes the hull seams and sheerline are all parallel to the hull axis at the same station.

Originally Posted by pistnbroke

Why are we bothering to try to help someone who cannot even come back and give us some more details on the boat he is trying to build?

Perhaps he is on holiday it is august ........

Eight weeks seems a long time: I think he's left ... not everybody can handle Hoyt's sense of humor ...

About S&G: I agree the laying out and drilling is a pain but the worst part is trying to cover all the stitches with epoxy then having to sand them down ...

[tom28571]

Originally Posted by ancient kayaker

There isn't one, see post #4.

About S&G: I agree the laying out and drilling is a pain but the worst part is trying to cover all the stitches with epoxy then having to sand them down ...

Ok, here is a method that is fairly accurate for small changes in length. Lay a batten on the sheer and mark off the station locations. This will show the actual length along the sheer between stations of the S&G plan layout. Increase these individual dimensions by the desired 10% on the S&G layout. Note that the actual amount of increase will be different for the different stations. Do the same for the chine and keel. Fair (loft) the new patterns by any acceptable method.

The result will not be perfect but will be close enough to allow the new patterns to fit well and will not distort the hull shape.

Terry, if you are having trouble covering the stitches, the solution is to epoxy tab between the stitches and then remove them before laying in the whole filet. A good application tool and technique is part of a good filet job. There is no reason that filets should have to be sanded if done properly. The solution is to lay on the fiberglass tape(s) before the filet sets up and clean up all epoxy dabs. If there are runs, you are using too much epoxy. On big filets on larger boats, use peelply to avoid sanding. Epoxy joinery is messy enough without adding to the work or mess more than necessary.

[ancient kayaker]

Originally Posted by tom28571

Ok, here is a method that is fairly accurate for small changes in length ... The result will not be perfect but will be close enough to allow the new patterns to fit well and will not distort the hull shape ...

... maybe if it's a canoe or somesuch. We really need to see the lines to be able to advise further with any certainty.

Originally Posted by tom28571

... Terry, if you are having trouble covering the stitches, the solution is to epoxy tab between the stitches and then remove them before laying in the whole filet ...

Agreed, that would be the method I would use if I did S&G; keeps the fillet size down, which is especially important for neatness if the angle between the planks is getting close to 180 deg. I watched a buddy of mine trying to get epoxy fillets done neatly with the stitches in place: he's a former professional furniture maker and is obsessive about finish, and he was so discouraged by the results that the boat is still unfinished after several years.

Most hardware stores sell a nice, cheap plastic tool for forming tidy fillets, it's intended for smoothing out caulking and bath tub sealant.

I haven't used peelply but I'll bear it in mind. I have used chine logs for several years and in general I minimize epoxy - I'm cheap but epoxy isn't I have read that the seams can be held together with dabs of super glue while the stitches are removed, but I haven't tried that yet. I assume that would be the thick variety as the thin stuff would vanish into the grain.

I've seen videos of the pros shaping the fillets - with masking tape to get constant width - it's true artistry but my hands aren't steady enough to do that. I was into calligraphy way back, even used to do custom certificates for special occasions, until I damaged some nerves in my hand a couple of decades ago - had to learn to write left-handed - so one of my fillets would not be a thing of beauty!