: We finished our station molds but we cannot figure out how to do the layout for the bow and stern molds.
: We are working out of a book called "Kayak Craft" by Ted Moores. I've got as far as laying out the
: bow and stern which is the last step before I copy them to wood. At the moment I'm stuck with figuring
: out the sheer line and deck line of the end molds. When this is done I shall have to go and find a beer
: as a reward! Can you please help me figure out how to lay : out the deck line? Where do you get the
: dimensions for it from? Are they off the table for the deck? if so is it the half breadths or the heights?
: Do you get it from the pro or the sheer.
: John & Ian

I’ve been struggling with Steve Killing’s offsets for the Endeavour 17 for a couple of weeks. While it has proved to be a great exercise to get familiar with my CAD program, the offset tables have proved troublesome. After I drafted the drawings of all the stern stations I realized that I had misinterpreted the sheer heights and had to redo them all. Although, they would have made an interesting canoe.

I, too am at the stage of working out the stem and stern profiles out beyond the 16 and 0 stations. As you know, there are no offsets provided in the book to draw these profiles. I was too stupid to post a question, so I too, didn’t know the stem offsets were available a the Bear Mountain Boat Shop web site. Go to the page for the book, then the page for FAQ’s, find the question “Building Tips: “I am building one of your kayak's, can you give me more detail on building the stem mold?” It’s about a third of the way down the page. Click on the “additional offsets” in the answer.
http://www.bearmountainboats.com/books.asp#kayakcraft

This might get you directly to the offsets page.
http://www.bearmountainboats.com/0-kayakstems.asp

Without knowing about this posting, I developed the bow profile by interpolation. This is somewhat involved so I’ve posted drawings to help explain it. You may what to access and print them for reference. Hopefully, this explanation will address all the questions you raise about Killing‘s offsets. They are found at:

Yak Album
http://albums.photopoint.com/j/AlbumIndex?u=1502758&a=11341576

I called the first drawing Lofting1. Very creative name, no? It shows half of station 10 with a plot of each offset provided by the book. One word of warning. The tables are in a different order than in the book. I’ve reversed the order of the half breadths and heights tables in the offsets with the drawing. The dimensions are in decimal inches, ‘cause that’s how I have to enter them for the CAD to plot them. This requires running them through a spread sheet to convert the fractions to decimals. One-eighth inch is equal to .125” which is rounded to .13”, and so on.
Lofting1 is in the album URL’ed above, but you can directly access it at:
http://albums.photopoint.com/j/ViewPhoto?u=1502758&a=11341576&p=40677191

Look over how I’ve used the offsets provided. Each plot point has a notation where it came from. The sheer offsets are the most confusing because Killing uses this term to refer to four different plot points on the station. I only figured this out by plotting all the possible sheer-profile combinations and eliminating those that clearly fell outside any possible use in describing the form.. I reversed the order of the tables to keep this clearer to me.

The sheer offset found in the half breadths table (my table 1) is the distance from the centerline (CL) out to the side of the hull (11.3125“). But to plot this you need a second dimension. This is found at the sheer offset in the heights table (my table 2). This offset is 7.25”. Yeah, but from what? From the point of origin (PoO). This is the 0”-0” plot, which marks one end of the centerline. All offsets are measured either out or down from this point. So, the sheer (Killing throws this term around, for the purpose of this sentence he means the upper outside corner of the deck planking) is out 11.3125” and down 7.25 inches from the POI.

What about all those other sheer offsets? I haven’t plotted the sheer offset from the fourth table Killing gives. In the case of station 10 that offset is 11.5”. I assume this represents the measure to the outside of the rub strake as the maximum beam is 23.5” at station 9 and the table 4 offset for 9 is 11.625”. This would give a beam of 24.25” enough for two 3/8” thick rub rails.

Then there’s the sheer offset from the deck heights table (my table 3). For station 10 it’s 3.625”. This is the one you’re looking for, I think. Again, through the process of elimination, I decided this is the measure for the height of the deck at the CL. If you plot each station’s table 3 sheer as a distance down the CL from the PoO they will describe the profile of the deck. That’s why Killing calls them the sheer! I only became convinced I was right after plotting a few deck sections and seeing they worked out.

The offsets for the hull waterlines, and buttocks are pretty straight forward, as are the deck height buttocks. The profile offset in table 2 (14.6875“) is, like the sheer in table 3, plotted on the CL. This describes the profile of the bottom. Some further confusion comes from the profile offset in table 3 (7.5625”). My guess is that is the distance down from the PoO to the top of the hull planking. The deck is a quarter inch thick. This dimension is close to a quarter inch greater (or lower) than the table 2 sheer offset for all stations. If I’m correct, this would also be plotted with the table 1 sheer offset out from the CL. I show this on the drawing, but left this out of my plots because it screws up the fairness of the hull in this area.

So when you plot all these eighteen points, and using a spline draw the deck outline and the hull shape, you should get something that looks like Lofting2. (Complete with the knuckle just below the 10” WL.) Now, I’m still not sure if this is the profile of the form or the outside of the hull. I think it’s the outside of the hull and the quarter inch of hull planking has to be deducted from it.
Lofting 2
http://albums.photopoint.com/j/ViewPhoto?u=1502758&a=11341576&p=40640177

The rest of this only would apply if you didn’t have access to the Bear Mountain offsets. After you have plotted seventeen forms, in my case 25 forms, you will have the forms of 17 stations which represent 16 feet of the boat. The nut is getting those other eleven inches. Without any offsets, I decided the only way to do this was to extend the sheer, deck and bottom lines to a given distance ahead of the last station in a way that they remained fair.

To do this I laid out sections 4 through 0 at 12” intervals and aligned by their common waterlines. I then drew a fair deck line profile to a point 4” ahead of station 0. This gave me a point out 4” and down 1” from the PoO. This point then became the point where the sheer and bottom profile also terminated. By keeping these lines fair the bow profile was described. The Lofting3 drawing shows the layout as it was done in CAD.
Lofting3
http://albums.photopoint.com/j/ViewPhoto?u=1502758&a=11341576&p=40640183

Once the bow shape was developed it was easy to pick up plots of the shape from the station 0 PoO. There are four horizontal references (Y axis) and three vertical references (X axis) which define the shape of the bow. They are shown on the drawing Lofting4. The Y’s are measured down from the PoO and the X’s out (forward) from the face of station 0. Obviously, I’ll use the Bear Mountain offsets for the stern.
Lofting4
http://albums.photopoint.com/j/ViewPhoto?u=1502758&a=11341576&p=40677180
Now, about that beer.