Thursday, October 28, 2010

12/08/2010 decoding the dinghy plan - Wei Shi's blog

12/08/2010 decoding the dinghy plan - Wei Shi's blog

Yesterday was the last day of this week for the course. Our mission was to decoding a dinghy plan and interpret it to a table which includes profile offsets and half breadth offsets for the frame of the dinghy. AutoCAD was the software we used.


The first problem is that the table of offsets we found on the student drive did not match the dinghy plan. There were six stations (plus one half station) in the plan, but only five in the table. There were other differences between the plan and the table as well, including number of buttocks and waterlines. So before we started to measure the offsets, we need to create a new table according to the plan.

After we made the correct table, we started to measure offsets. There were lot of offsets needs to be measured, so if you keep them on the screen, it will look like a mess. And you can not recognized those measurements yourself when you want to check them later. There are two ways to keep your screen clean: the first is to delete your measurements after you fill them in the table; the second is to create several new layers in AutoCAD for your offsets, for example, you can create a new layer for your offsets for sheer, then another new layer for canoe body, then you can just hide them when you done the measurement. Of course I used the second way. It is easy for me to check my measurement later and to keep the screen clean.

The second problem was the chine in the half breadth. When you zoom in to the chine, you can find there are two chines. There should be only one. The reason for this is that because Chris drew the plan in Autoship, and the program defined the topside and the bottom side of the dinghy. When Chris faired the dinghy, Autoship calculated the topside and the bottom side separately, and then we got a gap between the topside and the bottom side. This is not a big problem, as the gap is quite tiny. But it is quite confusing when we saw this gap first time. The solution is pick your chine for your measurement, and delete another one.

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