Sunday, October 31, 2010

Small Craft Building: Week 4

Monday
This morning, I started with beveling the stem. It took me about 40 minutes to finish the beveling and get the stem the right shape.Later, the stem was fixed to the jig and ready for the bottom.

Sebastien continued working on the midship section, while Kenny and Tian continued working on the transom.

Later in the morning, Jade and I worked on the beveled frame. Using batten and wood block to measure the bevel of the frame (for the topside of the dory).

In the afternoon, we put the bottom on the frame. Clue it to the stem and transom. We also used crump and screw to fix it to the frame and bend it to the right shape. We had a small problem with midship section as we found a gap between the midship section and the bottom. Vaughn's recommendation was to bevel the midship section's surface which was attached to the bottom.He showed us how to use 'plane' in style: quick and accurate. It only took him about 10 seconds to fix the problem and get the midship section the right shape. I did not even got a chance to make a video. Quick hand Vaughn.

It seems we are a little bit behind as there are only two weeks (8 working days) left for our dory. Tomorrow we plan to finish the topside which include 4 pieces of plank (scarf them and glue them). And we will also finish the transom fashion pieces. Hopefully we can turn the dory up next Monday and start to work on the inside. 

Tuesday
Our goal for today was to scarf topsides and glue them together. So we can put them on the bottom and frames tomorrow. This goal made today a combination of good day and bad day. Anyway, it is a challenging goal.

The reason why this is a bad day is quite simple: we made an big error on scarfing. We scarfed the wrong side of the plywood. Which means that we can not put two pieces together. We forgot what Chris told us: check twice, cut once. I think this is because everyone in the team put too much attention on the shape of the topside as this is our first time dealing with flattened developable surface. We ignored basic skills on scarfing: mark the scarfing side, and flip it over to check it. We did not notice the error until we started to put scarfed pieces together. This is really a bad news for the team.

Luckily, after discussion with Chris, we found that we still have enough space to fix the error: cut off the wrong scarf surface, and make a new one. The plywood is just enough for this cut off. This again proved Chris' advice: always make it bigger than the plan. this second chance is quite an encouragement. The team decided to work on the scarf and finish the gluing today. Although this made us stay in the workshop until 6 pm, but this is definitely worth it.

Another exciting thing is the sanding machine. This powerful machine speeds up the scarfing and helps to save a lot of time.

Kenny glued the transom fashion piece. It took him lot of effort and time to fix the shape of the fashion piece.

Wednesday
Today's major task it to glue two garboards (lower topsides) to the bottom and midship frame. In the morning, we cut the garboard to its shape on the bandsaw. This process includes two steps: first, we cut two boards to it approximate shape; then, we nailed two boards together and cut them to the exact shape at once.

The next step is to plane their edges to make them nice and fair. Then, we put the garboard on the temporary frame, locate a fix position by screwing a hole through the garboard and the midship frame. There are several preparation work need to be done before we start gluing: put tape on the edge of the frame to prevent to glue the frame to the garboard;  spread two layers of glue (first time without powder, and second time with powder). And then, we push the garboard against to the bottom and use nails and tape to attach garboard and bottom.

There are two ways to attach garboard to the bottom. One is to use nail and the other is to use tape. We decided to use the combination of these two method. On one hand, we can get less nail holes than simply using nails; on the other hand, as we are not confident (giving consideration that this is our first boatbuilding experience, we think nails, as a more conservative way to fasten the garboard to the bottom, is safer). After fastened  two garboards to the bottom, we also glued the out edge between them.

Chris (tutor) also showed us an efficient way to fasten garboard to the bottom. Use a wood block, and put it between the garboard and bottom, screw through the garboard from outside to the wood block. So the block and the screw play roles like a cramp which helps to push the garboard and bottom together.


This is not the last working day of this week, as we decided to continue our work tomorrow.

Thursday
Got to the workshop at 10:10 am and started today's work with beveling the garboard. It is a little bit confusing with the bevel edge. Consulted with Chris (American) and Chris (tutor), and got several helpful advices. We used saw to cut a small gap on the garboard edge at each station (except station 0,1,2, this is because of the bevel angle of these stations, the intersects will be too high) and the transom. This gap plays as a role of the extension of the frame, and its end point is the intersect of the garboard and the frame edge. Then we used a batten to draw a line through these points. The first line was too high for bevel edge and the second was little bit low, so we decided to take the middle.

After beveled the edge, we measured the size of the strake (the upper topside), and lofted it on cut board. After several times of checking and arranging it on the plywood sheep, we get our strake (as the process is exactly the same as the starboard, so this time it is much easier). One thing needs to be noticed is that we are also going to cut the bulk head from the same sheet, so it took us a while to arrange the cutting plan in order to get the most out of the plywood sheet we have.

Then it is time to scarf the strake pieces. This time we double checked the scarf surface and make sure that they are the right sides that should be scarfed. We marked them and used the belt sander. Then, we planed them by hand.

After scarfing, we spread glue on scarf surface (twice, one without powder, and the second with powder). Fixed them on the table. Next Monday, we will cut them to the exact shape and attach them on the boat.

Thursday, October 28, 2010

Great! use Blog This (an free extension for Google Chrome) to move my blogs to blogger from typepad

Moving from typepad to blogger is a good idea for our course blog, but one thing that really annoying is that there seems no way to move our old blogs directly from typepad. I found a good way, at least for Google Chrome browser. Download the free extension Blog This! (link: https://chrome.google.com/extensions/detail/pengoopmcjnbflcjbmoeodbmoflcgjlk), install it to your Chrome. Then open your post in typepad, copy all the contents (including text and pictures). Then click 'blog this' button on your chrome (this will open a new window which is exact the blogger style posting window), past all the content to the new opened window. Click 'publish'. And then, everything is done. Your old post is now posted on your blogger blog, including pictures!

One deficiency is that you can not label the post in Blog This!  you have to edit it back to your blogger blog.

Notice, Blog This! is only for Chrome. Have no idea if there is other versions for IE or other explorer/browser.

10/08/2010 Decoding the Boat Plan - Wei Shi's blog

10/08/2010 Decoding the Boat Plan - Wei Shi's blog


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2010-08-10 15.14.10

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)

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.

Review of Oilstone Box - Wei Shi's blog

Review of Oilstone Box - Wei Shi's blog:
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)

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.

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.

This is my finished oilstone:
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2010-08-10 15.15.01
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2010-08-10 15.29.04

AutoCAD Assignment - Wei Shi's blog

AutoCAD Assignment - Wei Shi's blog:

"AutoCAD Assignment
Yesterday we did an AutoCAD�assignment. We were asked to draw centerboard and rudder according to an existing plan in AutoCAD. Our drawing should include several different layers for lines, dim, text and we need to make new layout in paper space to display our drawing in right scale.�

The assignment included five stages:�

1.Sketch. We need to sketch the plan on paper, copy necessary information from the original plan. I think this is the most important part. The sketch will tell you what to draw. It provides basic information for the assignment.

2. Drawing in AutoCAD. Follow instructions of the assignment, create different layers, create drawing from the sketch.

3. Print out draft.�

4. Mark out. Check your draft with Chris, and to see if there is any mistakes. Mark them out, and then go back to your computer and fix them in AutoCAD.

5. Print the final drawing.

At 4 pm, we handed in our marked out draft and the final drawing to Chris."

AutoCAD, boat plan and faying surface - Wei Shi's blog

AutoCAD, boat plan and faying surface - Wei Shi's blog


This morning, we started with a discussion of our feelings of drawing a plan in AutoCAD. The small boat was designed for beginner boatbuilders, so as the plan itself.We got six sheets of plans. And guess what, everyone seems confused, because we can not decode the plan.As we were asked to draw the plan in AutoCAD, we found it is so difficult to duplicate it because we can not find enough measurements!
This proved a fact: for a boatbuilder, knowing how to use AutoCAD is far from enough. AutoCAD is powerful and useful tool, but you need to combine boatbuilding knowledge with your AutoCAD skill in order to get expected outcome (we have done several drawings in AutoCAD: tool box, oilstone box, stem section, deck camber, scupper hole...I think everyone in the team now knows how to use AutoCAD and has got basic drawing skills). That is why programmes such as AutoCAD are only computer-AIDED design programme.

Luckily, the course of boatbuilding is the exact process for our learning of boatbuilding knowledge. Chris showed us this morning the relationship between the faying surface and the PT (Plank Thickness).Actually, this is one of those difficulties we had in yesterday drawing. The length of the faying surface is PTx4.This is one of those important rules for boatbuilders.
2010-09-07 length of the faying surface