C12 Frame Question

Chuck · Post by **Chuck** » Fri Jan 10, 2003 9:17 pm

I am in the process of cutting out the mid frames for my C12 and have come up with a question - actually, I would like some confirmation on my proceedure before I actually make my cuts.... The nesting drawing that shows the B and C frames (with the B seat between) on the sheet of 3/8 plywood shows a tight fit to get all of these peices on one sheet widthwise. If I read the plans right, we should be cutting the frames to their exact outside dimensions, and not the dimensions shown on the stationing detail and what the How to Build notes suggests (and trimmed later). My question is that when laying out the frames, we should actually be drawing some of our layout points for the top corners of the frame off the sheet of plywood since there is no actual dimension given on the framing detail for the top leg of the frame (only the stationing detail). When interpolating between the points (one on and one off the sheet), we will get the true corner. Does what I wrote above make sense and is it the right way to go about laying out the frames??? Thanks in Advance.

Post by **jacquesmm** » Mon Jan 13, 2003 9:29 am

See our tutorial about cutting frames in the HowTo section. Frames B and C are very simple: no fancy sides sticking out and I see all the dimensions on D224/4. What do you mean by "leg detail"? There is nothing else to those frames than what we show on the drawing. Are you assuming that they extend above the seat? They don´t.

Chuck · Post by **Chuck** » Mon Jan 13, 2003 10:18 am

I agree that all the neccessary dimensions are given on the sheet - my question has to do more with how to properly layout the frames. I´ve read the how to tutorial and I understand how to layout the frames, but I think that this case is a little more complex than what is shown in that tutorial. I am at work and don´t have the plans in front of me right now, but I recall that if you layout the frames based on the stationing details, the C frame, the B seat and the B frame will not all fit width-wise on the sheet. The frames have to be cut to their final heights in order for them to fit. What I am trying to confirm is that to layout the frames, we would have to use the stationing details (since that is the only detail that shows the widths of the frame w/ respect to the center line) with some of the points along the top part of the frame drawn off of the sheet. I hope that I said that more clearly, but it is hard to describe with just words.

Post by **jacquesmm** » Mon Jan 13, 2003 10:27 am

OK, I see. Yes, to save plywood, you should cut to the exact shape. Only cut B and C, assemble the boat and then use what is left to cut the seat top. If you want to measure exactly, it is easy: draw the centerline of the seat top and use it to line up the other parts.

Chuck · Post by **Chuck** » Mon Jan 13, 2003 11:18 am

Thanks... That is how I did it - I drew the centerline for all three parts first and then began by doing the layout for the two frames first. That was when I noticed that the seat top would not fit if the frames were cut to the dimensions on the station details. Was I correct though, by laying out the top corners of the frames (according to the dimensions shown on the stationing details) off the sheet of plywood by a couple of inches (again, I don´t have the exact dimensions in front of me right now)?? Then, I connected the points between the top corner and the chine/side panel point, and where that line intersects the edge of the plywood gives the correct length of the top of the frame. I think we are on the same page now - so hopefullly this question is clearer. Thanks for going through this with me - I hate to find out my frames are not wide enough when I go to stich everything together.

Post by **jacquesmm** » Mon Jan 13, 2003 12:31 pm

You can not go wrong with the dimensions for the frames as long as you don´t change them! The only possible problem would be that your nesting would be too tight and that you need another sheet of plywood. If, on the plywood sheet, you drew the centerline for the seat as shown on D224/5 and measured from there, you can not go wrong. And since we show dimensions from a centerline, I don´t see how anybody could do it differently.To be certain, the lower corner of Frame B is at 1-5/8. You don´t really need that dimension and we will not add it to the plans because it would like an invitation to measure from the corner and we don´t want that. All together, you have around 2" safety margin on that sheet of plywood.

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