Wei Shi's blog

16/08/2010 First day of lofting

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Today is the first day of our lofting training. Well, have to say that lofting a boat in its full size (even it is only a small dinghy) is very interesting, but at the same time, it is very exhausting as well. The first impression of lofting is that every tool used is super size (see the picture on the left). Everyone got a big cut board whose dimension is 4000mm x 1250mm. I have never drawn on a board of such big size.

After discussion with Vaughn, we decided the location of the LWL for the profile and the CL for the half breadth. LWL and CL are those first to be drawn on the cut board. Stations are the next. Drawing stations are quite tricky, and you have to be very careful about the error of every station line. Because the sum of the error of each station might be quite big. Actually I got 5mm longer of the Loa. And it took lot of time and effort to fix it. Can not imagine how it will be to loft a big yacht with 21 or more stations.

After finish the LWL, CL and stations, I started to draw the sheer according to values in the table of offsets. But Vaughn stopped me and told me that the right order is to finish the grid first. This does make sense. Then I spent rest of the day manipulating those big tools to draw water lines and buttocks.

Picture below: Tian is working on his F.P.

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First try of SolidWorks: Toolbox

This is my first try of SolidWorks, I first watched Chris' tutorial video for making a toolbox in SW and then tried myself. Very powerful software. The first toolbox I made was first drawn in AutoCAD, then imported into Rhino for modelling and finally rendered in 3ds max. The problem is that considering the several times of data transfer and different softwares, the final product is not accurate enough. SW provides a comprehensive platform to do all these works. 

Review of Oilstone Box

The oilstone box is the second project of the 'box series' (well, the first was the toolbox project). From my point of view, the process of making the oilstone box is much smoother than that of the toolbox. Everyone already knows how to use those machines and how to process the work with different tools. 

The first step is preparation. Everyone got a plank with the length of 630mm. D4S the plank by using buzzer, thicknesser. 

The second step is to mark out according to the plan.

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The third step is the real challenge. We need to make an inset in the middle of the plank for the oilstone. The plank was drilled and chiseled. However, the process was really difficult, especially for the chiseling. It is easy to chisel a hole in the middle but difficult to chisel a straight line at the edge of the inset. More over, the side and surface of the inset are very rough, it is even more difficult to smooth them. It took me almost the whole day (Monday afternoon and Tuesday morning) for chiseling the inset and frankly I am not satisfied with the outcome. Another challenge for the inset is that you must make sure it fits the oilstone. But the two sides (the black side and the red side) are not the same size, and the dimension of the stone is not exact the same as the plan. At first, I made the inset in the bottom according to the size of the small side (red side) of the stone, and then I found it was too small for the black side. So I had to chisel the inset bigger. Finally, I got the right size for the inset: make it a little bigger than the oilstone. After all, the biggest problem is not that you can not put your oilstone in, the biggest problem is that you can not get your oilstone out (if the inset is just the size of the oilstone, the stone may get stuck and difficult to get it out)

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After finishing the inset, plane was used to make bevel of the top of the box. This was my first time using plane to make the bevel. Thanks for Chris and Vaughn for showing me how the use the plane.

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The final step is to make the hollow at the bottom. This is even harder than the inset. I used bandsaw, chisel and spike shaver and finally I got the shape of the hollow.

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This is my finished oilstone:

Tutorial 2: AutoCAD practice 2, dwg file

This is the dwg file for tutorial AutoCAD practice 2, you can download it from following links:

https://docs.google.com/leaf?id=0B9cfL8fjmev0YjNkZDIxMDEtYzM4Mi00MTg5LWI2YjAtMjdjNjMzZWFhNzlk&hl=en

Tutorial 2 dwag

Tutorial 2: AutoCAD practice 2

hi, guys, this is the second AutoCAD tutorial, this time we are going to draw the following drawing:

Step6

Step 1 Draw 4 concentric circles ( radius: 25, 40, 85, 100)

Step1

Step 2 use command 'divide' to divide circles (radius 85 and radius 100) into 20 segments, and change point style with command 'ddptype' (point size: 2)

Step2

Step 3 Draw 2 arc, use arc 3 points

Step3

Step 4 Trim those arcs

Step4

Step 5 Array the 'horn', angle: 360, number: 20

Step5

Step 6 Delete the circle (radius 100) and all points to finish the drawing

Step6

This is the end of this tutorial, i hope you all enjoy it.

12/08/2010 decoding the dinghy plan

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.  

10/08/2010 Decoding the Boat Plan

This morning , we started with discussing those joints we made yesterday. We discussed essential skills for making a joint, including cutting, dressing (D4S, D2S), ratio (1:6, 1:8), sawing, chiseling, sketching, etc.. We still have lot of work to do to improve our skills. Chris also pointed out that in order to get the job done, marking out is an important step between the start and the finish. 

After this review, Chris started to give us introduction of lofting. Today's topic is the decoding the boat plan. The table of offsets (which tells the location of important intersects in the lines plan) and Simpson's 1/3 rule (which is used to calculate the displacement of the boat) were introduced and explained by Chris. He also explained the link between the table of offsets and the lines plan.

Later in the afternoon, Chris went one step further to show us how to decoding the lines plan into digital by using AutoCAD to create a table which tells locations and ordinates of cheer and buttocks. We are going to continue this tomorrow.

PS: the toolbox and oilstone box are all finished now, I am going to review these two works (including the process, finishing, skills an tools etc. later this week)

10/08/2010 Blog Plan

Vikel came after lunch and talked about how to blog our daily progress of the course. He recommended us to adopt Gibbs' reflective model as the step by step guidance for our blogging. (see picture below). According to Gibbs, the model for reflection includes 6 steps: description, feelings, evaluation, analysis, conclusion and action plan.

Gibbsmodelreflection

As far as I am concerned， I think this model will play a very positive role in our studying process. It provides a frame to think about what we have done during the day and a guidance for analysis the good (success and god job) and the bad (mistakes or errors). 

Moreover, Vickel also discussed to following this model for the upcoming lessons. For example, we are going to do lofting and AutoCAD in the coming weeks. We can do some research about lofting in advance. I will try to follow Gibbs' model for the lofting lessons.

One question about adopting Gibbs' model for blogging is that it might put additional pressure and works. The daily courses are quite intensive, especially with Chris, as he always keeps on challenging us. If we follow Gibbs' model to review our daily study, there might be too much to think about. Of course we do not have to go through every detail of the day, but details are important. 

Anyway, Gibbs' model provides a very good framework to review our daily study and progress, critical thinking is as important as problem solving. The boatbuilding course gives me a fresh experience of learning, and I am going to try Gibbs' model to record my experience. Cheers.

Blog Plan

 

wooden boat website

http://www.woodenboat.com/

test of trammel arm. Smart BOATBUILDERS

This is a test of how to draw angles with trammel arm. Smart BOATBUILDERS

Test of trammel arm