Lofting what I did -trying to figure it out on my own

As the title says this is how I lofted out the plans for a Canoe. Ted Moores book "Canoe Craft" makes a statement to the effect 'lofting is beyond the scope of this book'. Ugh, the reason I bought the book was so I could make a canoe. There are plans there, and if you read carefully, you will see that it describes how to interpret the plans (ie the tables of numbers) Lofting the stations is really quite easy. Lofting the Bow and Stern Stem Molds is a bit more challenging for me at the time.

I'm not sure I did this 100% correctly, as I said, I figured it out on my own.

Before try and explain lofting the plans, there is one bit of information I noticed. The book makes a statement to the effect 'the points are to the outside of the hull, thus you need to subtract the thickness of the hull'. However when comparing the points to the drawings, it appears that the table is to the inside of the hull. so I did not bother with the subtraction.

Also I recommend plotting all the stations on one piece of paper, this will Allow you to spot any errors as you plot. It is also pretty cool watching the boat take form on the paper. At least I thought so.

Okay, the tables are of course simply X-Y plots of points. For the book "Canoe Craft" These points are provided in two tables. The table of Heights (A.K.A. Water lines) and the table of breadths.

  1. Obtain 1 (or maybe 2) large sheets with a 2inch by 2inch grid on them.
  2. Profile points, these points are simply the bottom edge of the canoe, it is placed on the zero breadth line. This point on the largest station will tell you the minimum length of paper you will need to plot the canoe out on. ( 24 - 26 inches should fit)
  3. Plot the heights. The fist column is the table labels has entries of the form Butt n". Here "n" indicates which vertical line you use to measure up from. The Row heading indicates which Station you are plotting out. So 'Butt n' gives you the x- coordinate, and the value in the table under the current Station heading gives the y-coordinate. Follow the Butt-n line up a distance indicated and mark a point on the line. Do this for all the points for one station, then proceed to plotting the half breadths.
  4. Plotting the Half-Breadths. This is the converse of plotting the heights. Here the first column indicates the waterline of interest 'WL n'. Say n is 2, then this is the 2" water line. Follow this line out from the centerline, and mark an point as indicated in the table. If there is no entry in the table then there is no crossing of that Water line. Mark all the water line points for the current station.
  5. Shear Point. This is the point that will mark the shear line, that is where the top edge of the canoe is. This point is unlikely to land on either a water line, or a half-breadth line. Here the X-coordinate is given in the table of Half-breadths, and the y-coordinate is given in the table of Heights. It's that easy, plot the point.
  6. Connect the dots. At this point you should have all the points plotted for one station. At this point all I did was connect the dots with a strait line. (I did my fairing on the ply wood once I transfered the dots to the wood.) Connecting the dots with a line so we can prevent confusion later, also with a bit of imagination this will result in seeing the boat come out of the page.
  7. Okay, repeat steps 2 - 6 for each station.

    Plotting the Stems. Okay, this is a bit trickier... I'll tell you how I did it but, I ended up having to raise my stem molds up. I think I know why, but I'll have to break out the ruler, and mold piece and check. First off go to the Bear Mountain boats web page and see if there are correction for the stem on you canoe. (for sure if you are building the Ranger or the Huron Cruiser). On this page you will also find a great diagram for plotting out the stem molds. In fact I'll say that picture is worth a thousand words and leave it at that. the only real trick is getting the shear point, which will fall out in the canoe building process when you are putting on the gun-whales, trust me. when you are putting the stem's on make sure you leave them extending down as much as possible so you can cut to the right height latter. I did not, trying to get the point right on to start with (dummy), which caused me a bit of worry.

    Do not for get to subtract the thickness of the inner stem from the outside line you plot from the data in the book.

    Reading the table the 'foot-inch-8th-(+/-)' notation is described in the book. Good Luck

    Here is some input from Steve Killing for lofting the kayaks in kayak craft. It includes a picture.
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