C-17 Our first Build !

[David516]

Thanks Tony. Im working on getting that right (far) side to lay down a bit (about 1" to touch the frame) and I think I figured it out but not sure till I try it. Gotta tighten the center line a bit then very very slightly change position of the right (actually port side) lower panel which is trying to creep under the edge of the bottom panel. Nails not helping so I think about 2/3 that side need to be loosened a bit.
best case scenario the tighter center line forces the side panel from under the bottom panel.

[David516]

Did a little more tweaking today. I'm almost completely satisfied the hull is very fair.
I'm still unsure about the the hull not touching every part of every frame. Is that ok? I'm also having a problem with one of the lower chine panels refusing to lay flat on frames D & E. the hull appears perfectly even (when I push the one panel against the frames) and it's not under much pressure at all but it's impossible to get to lay flat. every time I try something like
re-positioning panels, tightening or loosening the zip ties in different places something else causes a worse problem. (see below photo).
what I was wondering was If I could temporarily hold the panel in place while I glue and glass the bottom and lower chine panels and possibly temporarily tab the panel to station D (MDF board) until rollover so that when I apply the upper chine panels everything will remain in place???
I'm thinking the panel might be warped since nothing I do resolves it.
Any assistance is appreciated !

[Eric1]

David, All I can tell you is that mine didn't touch every surface either. They were close bit not making full contact. If you look under my boat now there are still places that don't touch. All of that will be corrected when I glass the frames in place. That shape will have to be adjusted after glassing inside regardless. Concentrate on getting a fair shape. If you like go back to the early part of my build "Eric's C21" and read through it. I had many of the same questions you are asking. It will come together, Believe me.
Best of Luck!!!

[David516]

Most places are close or making contact. There are a couple of places where the non contact is more than an inch. I can adjust for it but i don't know if it will stay in place after the gluing. I also notice that due to the high humidity a lot of apparent warping is taking place.
My question is if i forceably overcome all this warping will the gluing be adversely affected?

[Reid]

David,

The hull panels are never going to touch the frames the entire way. Your goal should be to minimize the gaps to under 1 inch. Small gaps will be filled with woodflour/epoxy mix and eventually glassed over with tape and fiberglass cloth. Your biggest concern is not to have any flat spots in the hull sides and not to have any concave or convex curves in the hull bottom. These are difficult to correct after you glass the hull.
First, I would double check and make sure all your frames are accurate and square, both in distance apart and sitting at 90 degrees on the strongback. Next, I would play around with the zip ties. I prefer to hang all panels very loose and let them sit a day. I will then start to tighten the ties very slowly working my way from stern to bow or bow to stern. Also, use the method of cutting pvc pipe and placing that in between the zip tie and the back side of the seam. This will help keep an evenly spread apart seam and avoid binding in some spots which will cause larger gaps in others (particularly the bottom of the frame). Be careful not to stitch your keel seam to tightly. This is common among first time builders and often leads to larger gaps between the frames and hull side panels. Stitching the hull definitely takes patience but will pay off when you start to glue.
The last piece of advise before you glue is to use some painters tape and tape the back side of the seams. This will help you form cleaner fillets and save time when you flip the hull.
I hope this helps, keep fighting the good fight my friend!!!

-Reid

[terrulian]

My question is if i forceably overcome all this warping will the gluing be adversely affected?

The glue is very strong. However, if you have, out of necessity, used some weight or clamp or screw or bolt to hold together a particularly difficult part and there is a lot of stress on it, there is the off-chance it will pop when you remove the ties. In case you're concerned about this, while you're putting the putty welds between the ties, right at the stress point add a little glass tape. This will hold everything together and eliminate your concerns.

Couldn't get the panels to come together:


I gave up on zip ties in exchange for the power of a bolt:


I taped the interior just in case the glue wouldn't hold when I released the bolt. This looks cockeyed from the photo but is actually symmetrical, believe it or not:


This is not pretty, more like watching sausage being made, but it held fine, and the bow, with a bit of fairing, was just right. I'm not as neat as the good builders.


I never uploaded a close-up of the finished bow but here it is:

[David516]

Thank you Reid. I have to this point taken almost all of your advice and I find I still have to loosen some stitches in the midsection And I still need to add some battens higher up to get the sag out of the mid hull however, everything is almost perfectly lined up and may only require a slight adjustments as I was able to get the gaps inside under an inch.
The lower chine panels look pretty good to me but I don't understand what you mean about flat spots. The aft section of the panels are not curved whereas the forward half of the panels seem to be curved perfectly.
Is this what you were referring to?
I will be loosening the mid centerline zip ties to allow the lower hull panels to be properly spaced on the frames.
If there is anything else that you think I should be doing please let me know. Thank you.

[David516]

And thank you Tony for the explanation and the pictures.
I may be taking your idea for the bow since I have to move all of the nose panels in another eighth of an inch.
I am waiting to see what the rest of the boat looks like first after I do all my adjustments.
Actually if you look at the pictures I posted my hull looks very similar to yours at this stage except for the two problems I mentioned.

[David516]

This is whats driving me crazy!
I removed some stitches between frame C (third from left) and E at the centerline. I added some weight above frame C, The hull sits perfectly straight and fair.
When I re-stitch that area (whether loose or tight) and remove the weight, The bow just in front of frame C bulges up about 1 1/2 inches and screws up the straight centerline and some of the fairness! I cannot figure out the solution! I have completely unstitched and re-stitched all the panels twice and re-did that section several times all with the same result !
Any suggestions ?

[dbcrx]

Can you not just leave the weights on while you glue it. Or put a few ties through the frame to hold it down.