Stem face
Stem face is a crucial part of the lofting. If you just using existing intersects, it will be hard to get the right curve. Because the stem face needs more details. The solution is to go back to the CAD lab, using CAD to drawing several ghost lines to construct a new grid (with higher density of grid lines) for the stem face, and measure those intersects of the stem face and ghost lines, then you get your stem details. Once you figure out how to do this, stem face is an easy task.
Stem section (Wednesday, 25/08/2010)
After finish the body plan, I started to draw the stem section after lunch yesterday (Tuesday). Thanks Chris for his detailed explanation for how to draw the stem section. Once you figured out how to do this, it is not a hard task. Especially with a sticker (which has markings for moulding, 1/2 siding, PT), you can draw stem sections quickly. Following are steps:
-Go to the stem face and pick a point on the curve (point X), draw a perpendicular line (line A) to point X (you can make a guess by imaging the tangent line to the curve at point X).
- Start from the intersect of line A and the butt 50, draw a ghost line (line B) which is perpendicular to line A, with length of 50. Use the point X and the endpoint of ghost line (line B) to draw line C.
- As the PT (planking thickness is 4 mm, we need to offset line C (offset distance: 4mm) to get line D
- From the start point of line D, draw the moulding (32 mm), and get the faying surface.Then from the endpoint of molding, draw the 1/2 siding (15 mm). From the endpoint of siding, draw a perpendicular line to line D. Notice the round corner at the intersect of the mold and the siding.
- Add some shading.
Picture below: finished stem sections and the sticker with markings for moulding, 1/2 siding and pt (the sticker is made by Chris)
Wei, Great blog. Good detail and explaination of the process you are using. After all the lines are fair in Profile, half breadth and body plan, you will be then going back and lofting in the structual components. One of these is the stem. You will be updating the stem blogg as you go.
Keep up the good work.
Posted by: clovegro | 08/20/2010 at 09:25 AM
Wei, this is good stuff. I can follow the steps you have explain in this blog. It is very clear and exact. Keep up the good work.The tick sticks seemed to have made the job of drawing the sections quicker. No need to remember any numbers.
Posted by: clovegro | 08/27/2010 at 08:40 AM
How is it?
I've been thinking... what if you could do a series of short video clips on making a stem.
Perhaps you could do this on the Dory?
What do you think?
Cheers
Posted by: christopher lovegrove | 09/24/2010 at 02:28 PM