Seat stringers and making butterflies

[Maria CS20 104]

Hey all, I back, made good progress cutting materials for centerboard (hickory and black walnut for main portion)  made heavy of free materials.  Plan to biscuit the strips in the next couple of days and have friend who will plane down from 1 5/8 when cured then handle attachment for final shaping.  All hull pieces cut and ready to assemble, but I am confused on instructions.  Plan says to put seat stringer on after sides made up.  I have sides all marked to attach for both sides, but it looks to me you can't properly butterfly sides and bottom with them in place.  Additionally, it is advisable to use galvanized 3/4 inch brads to hold side walls in place when epoxying together?  They will be buried and covered in multiple layers of epoxy when done, am I on the wrong track?  Where can I get SS 3/4 18 gauge brads for my pneumatic gun (bostich)? Are they available?  Ringnails, are they hard to put in place?  Recommended method, since nails go through outside of the hull, through ply into the seat stringer?  I have an idea to butterfly firest and then set sidewalls.  OK?  ???

Jim A

[SUKIE]

Jim,

Although I'm only a beginner, I also had the same question on this step. I ended up attaching the stringers before the butterfly and it worked out fine. I used sheet rock screws, thru the hull panels into the stringers to hold them in place until the epoxy set good and hard, then removed the screws.

Only my opinion, and I'm sure there are others out there. Good luck!

And remember, one of the wise (notice I didn't say "old"!) boatbuilders on this forum told me early on, there are not many mistakes you can make that have not been made before, and almost none that can't be fixed.

[Randy C.]

Jim,

I'm building a CS17. I attached the seat stringers before I did the butterfly. I attached with drywall screws until the epoxy cured, then took out the screws( actually, I had to take mine off and redo after I did the butterfly because I mixed the epoxy wrong). Did the butterfly and everything turned out just the way Graham said it would. It's actually pretty neat the way it forms up into a boat hull. If you're careful doing your layout it should be fine(I checked mine 3 or 4 times, it just didn't look right, but in the end it was O.K.).

[Maria CS20 104]

Tried to respond yesterday, didn't accept message.  Do I need to taper the stringers before I butterfly?  Once done and attached do you lay temp out with the stringers on the outside of side panels, very bottom and very top, to have the flat sides against each other?  Only way I see I can come close to a good tight fit.  Or do the stringers not make a difference when they have been tapered down to 1/8" in the bow section.  This is the real part of my confusion.

THanks, Jim

[Peter HK]

Jim said

Do I need to taper the stringers before I butterfly?  Once done and attached do you lay temp out with the stringers on the outside of side panels, very bottom and very top, to have the flat sides against each other?  Only way I see I can come close to a good tight fit.  Or do the stringers not make a difference when they have been tapered down to 1/8" in the bow section.  This is the real part of my confusion.

Jim

I glued and tapered the stringers in place and then arranged the butterfly and glass taped the forward sections. You are right that it doesn't like to lie completely flat. It's flexible enough that it's not too much of a problem.

I did have a minor issue in that the top panels of the butterfly set with a slight misalignment in the aft 6 inches of the glassed section- the forward bit was fine. It was of no real concern because when 3 D I simply split the misaligned section with a saw and retaped it when doing the internal chine taping.

Off you go.

Peter HK

[Randy C.]

Jim,

I tapered and glued seat stringers in place before doing the butterfly. I think, and this is just a guess, the taper helps let the bow bend and form when opening up the butterfly. I taped the butterfly joint just how the instructions said and everything worked perfect. It is important, as the instructions say, to fiberglass tape both sides and bottoms at the same time to make sure everything is symmetrical when opened up(When fiberglassing I actually lined up the sides and put a screw in to hold from moving out of alignment, then did the same with the bottoms). I was skeptical about the whole process, but everything turned out great. I had to see it to believe it. When opening the butterfly, in less than a minute you'll have a boat hull.

[Maria CS20 104]

I think I have the general idea and I think, note I said I think, if laid out with stringers inside it is just a matter of minor handling to set into the forms instead of ring one side out from under the other and then bringing around to lay over by turning 180 degrees.  Any idea how far apart the stern of the side winds should be apart from the bottom of the hull when getting ready to set the side wings?  based upon all the pics I have seen it varys a bit depending on who is doing the layout, looks to me about five or six feet.  Any words of wisdom amoungst you pros?  Getting worried, I've build and or cut out all I can without proceeding with butterflying and sewing together and it has become time to make the ship or get off the pot.  Have faith, I will do this one way or another, just want your experiance and guidance before I take this GIANT step.

Thanks for all the great input, tappering was fun with the hand plane, especially after sharping the blades to a fine honed edge.

Jim Atkinson