Tuesday, November 23, 2010
Sunday, November 14, 2010
This is the final week of our small craft building project. This morning, we started with cleaning up the inside of the dory. Which means to get rid of glue. Then we realized that how much glue we have put on our boat. Kind of mess.
The bulk head is another task for today. Bandsaw and jigsaw were used to cut the shape of the bulk head. In order to make it the right size, plane and sanding were necessary. Before working on the bulk, Chris showed us how to find the exact location for the bulk (as the real dory is little bit different from its plan). First make sure that the boat is level (use level to check at the forward, midship and afterward stations of the boat), then put the midship frame back and make it right angle with bottom. Next step is to put bulk head frame back (make sure it is right angle with bottom.
Afternoon, we were preparing lamina for the quarter knees and Jade was working on the fore deck.
Monday, November 8, 2010
Last week, we set up a goal for today: attach the strake (upper topside) to the boat. It is good that we made it today, although this took us 3 hours extra work (We left the workshop at 7 pm).
The first thing this morning was to plane those two scarfed strake (port and starboard), and sand them. Next is to measure their exact size. We tried several times for the measurement.
Another important step is to make the Box Landing at the forward of the garboard and the strake. This requires good skills. Vaughn explained it to us. But I did not really understand until I started work on it. Well, practice helps a lot to understand. But I made a mistake by beveling the box landing too much. This resulted in a big gap between the strake and the garboard when we tried to put them together. The solution? Fill the gap with lot of glue.
In order to fix the strake, we spread two layers of glue, and then nail it to the garboard. This is not enough. We also use several sticks to keep pushing it against the garboard. This makes the boat looks like a spider rather than a dory. Then we fill the gap between garboard and strake with glue. The process took us lot of time and lot of glue.
|Chris (tutor) spreading glue|
It is good that we finished this today. Otherwise, it probably will us the whole week and drag us behind the schedule (as we are not ahead of it, so time really matters). I think we have finished the most difficult parts of building the dory.
Sebastien and Tian also finished the skeg this morning and we also glued them together. Tomorrow we will be able to attach the skeg to the boat. Good jobs, Team Morris.
The skeg gave us some problems today. First is that one of those two skegs are not glued properly, so we had to take it apart and re-glue it. Secondly, our skegs are 300mm shorter than it should be. So we had to extend it by scarfing. So we have to wait till tomorrow to put these skegs on.
There is another mistake in the stem cabin. We used the wrong nail (steel nail will go rust easily when it touches salt water. Copper, bronze or stainless nails should be used ) to fix it to the stem and did not use the block between the nail and the stem cabin (this makes it difficult to take the nail out. Fortunately Chris promised to take his tool tomorrow and help us to fix the problem).
The center skeg is also cut. James showed us how to draw the curve of the bottom on a piece of wood. And then we transfer the curve to the wood block and got the center skeg cut.
Chris (tutor) also explained the difference between lamination and sawn. As the boat will face constant waves in the water (which might be very strong and cause lot of shock on the boat),the sawn stem or midship frame is not strong enough for these waves. This is because as sawn stem or midship frame, there will be long grain and short grain areas. Short grain areas are very weak and easy to break. So lamination is better choice as it produces much stronger stem and midship frame. More over, we can learn more from lamination as it. By the way, lamination is also more expensive.
The first boat flipped over today! (see the video)
Team 'Hory Dory" flipped their boat (James is the owner) over in the afternoon. This is really a big step forward, not only for the team but also for all CAT program students. As this is a milestone for our learning process.Congratulations! Team Hory Dory.
Hopefully we can flip our boat at the beginning of next week. I am looking forward lot of sanding work.
This morning, Chris (tutor) came to us before we started our work, and asked us to take 15 minutes to discuss and make a plan for the rest of our small craft building project. The reason for this is that with a clear plan and goals, we can work 10% more efficient. Actually the final plan is almost as the same as we discussed before: skegs and gunnels are for today, and other components are for next week.
Chris (tutor) also talked details about fore deck, bulk head, thwarts and other components. Especially about the fore deck, as it is not included in the plan. It seems a real challenge as there are lot of challenging details. I will write more about the fore deck after we finish it.
Another important technique Chris taught us is how to get nails out of the wood. See the video below:
The skegs are more complicated than I expected. As we extended them yesterday by scarfing, this morning is for shaping skegs to the exact shape. The first thing to do is to draw the curve of the bottom of our boat and transfer the curve to skegs. James showed us a good method to do this. So this is not a problem. Then we plane off glue and sand skegs to make it the right shape. Then, skegs are put through big sander machine to get smooth surface and right thickness.
|Skegs going through big sander|
In order to install the skegs to the boat bottom, we have to fix the location of the skeg. Measured from the center line and draw lines for the skegs. And then we drilled several pilot holes on the bottom, these holes are right position for screws and reference for the skegs. After finished these preparation, spread glue on the skeg and put it on the bottom. Then screw the skegs to bottom to fix them.
After the skegs, it is our turn to work on the gunnels. Lot of cramps are used to hold the gunnel to the strake, screws are used as well. We made screws same common spacing.
It is good that we put skegs and gunnels on today. Tomorrow, we will do the sanding and clean up and we will flip over our boat tomorrow afternoon. One big step forward! Cheers!
Sunday, October 31, 2010
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.
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.
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
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.
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.
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.