Construction and Design Journal – 14ft Dory for Rowing and Sailing – Part 7

by Roy Heberger - Boise, Idaho - USA

KNEES and FRAME #4 – February 24, 2004

I went back to the lofting board to arrange the RBC laminations for the bow-stem and transom knees.  Using some of the scrap RBC wood, I made some braces to hold the bottom, top, and leading (at the bow) or aft (at the stern) edges of the laminations.  I use 17 RBC laminations at the transom and 16 at the bow stem.  Once the laminations of RBC were fixed into place, I made vertical perpendicular lines across the laminations at several locations on each knee.  I also numbered each lamination starting from the bottom and labeled the knees.  That way I will be able to place the laminations for clamping and gluing in their proper positions on a sheet of plastic without having to use the lofting board as a guide.

The aft edge of the transom knee will not go directly to the transom as I intend to brace the inside of the transom in its entirety at the bottom, along each side in the mid section and along the top.  These braces will give greater purchase for screws and epoxy from the side planks (hull and aft stowage cabin), bottom, and cabin top.  So the aft edge of the transom knee will butt up against the transom brace.  The butt will be formed as a straight line between the two surfaces.




The fore edge of the bow-stem knee will butt directly against the aft edge of the stem.  Note, I have made the decision not to develop a fair curve at the aft edge of the stem as I have done for the leading edge, thus leaving more material for greater weight below the sheer line and more strength.

The bottom of each knee will be a very slight fair curve to conform to the bottom and the dead rise of the keelson.  Note, as mentioned above, I will have a ¾” X 3- ½” oak “keelson” on the inside of the bottom running along the centerline from under the stem to the either butt up against the leading edge of the transom or to go under the transom.  I have yet to finalize that decision.  I’m thinking the oak is harder than the African mahogany, it may be a good idea to extend the keelson to the aft edge of the transom bottom.  We’ll see.

As to frame #4, I have nailed braces to the lofting board, thus securing each rib and the futtock into place.  I will re-saw the joints in position as was demonstrated at boat school to insure the best fit at each joint.  Tomorrow, I plan to drill four screw holes in all of the gussets in preparation for fastening them, glued to the frame joints.  Note, to accommodate the strong back during construction, I will not be attaching the cabin top rib or beam members to the frames until after the hull is completed and the boat turned right-side-up.  I will however brace them and re-saw those joints while each frame is on the lofting board for fitting and gluing.

Once frame 4 is done, it looks like I will be able to do about two frames at a time to allow for their spacing on the lofting board, the number of braces I made, and the set time needed for the West-System epoxy (I’m guessing 24 hours w/ the electric oil heater on in the garage).

All Fastened
Insiders Toward Stern
Insides Toward Stem
Planing Knuckle Starboard Sheerboard
Fitting a Plank

KNEES, STEM, and FALSE STEM – February 27, 2004

I set up the West-System resin and hardener with the new pumps today and got them working. I organized my work space for efficient use of the mixed epoxy and went at gluing the laminations for the knees together.  I had to run out and purchase more c-clamps so I could do both knees at the same time.  I’ll need the clamps later for the planking anyway.  I glued the knees in half sections with half the laminations in one cluster and the other half in a second cluster.  Tomorrow, I will glue the two halves together.  The West -System epoxy is very nice to work with and has only a minimum of odor.  I detected no noisome fumes like I had with the locally obtained epoxy I used on my solo dory.  (By the way, I forgot to mention that my local source for epoxy no longer exists.  That’s just one reason I decided on West System epoxy.)

I made up a steamer using a gas stove, tea kettle (its back in the kitchen now), some drain hose, and a 4-inch-diameter PVC pipe.  The four inch pipe is great for scantlings and the cottage cheese container covers fit the pipe ends perfectly.  I steamed a 4-ft. length of RBC for the false stem for about three hours, removed it using leather gloves and set it up with weights to begin putting a nice bend into the wood for the false stem.  I anticipate using epoxy on the false stem, so I want to have the RBC all dried out by the time I fasten the RBC to the stem.

Using the table saw, I trimmed off portions of the leading edge of the stem.  I do not have a band saw, so I will have to plane the bevels in by hand.  I’ll start that soon. 

FRAME 4, KNEES, TRANSOM, STEAMER, and FALSE STEM – February 28, 2004

Using my pull saw, I re-sawed the four joints of the station 4 frame in position on the lofting board.  I then placed plastic under each joint, mixed up a batch of epoxy, glued the remaining joints on stem and transom knees, added wood flour to the epoxy and glued the frame joints in position on the lofting board.  Don’t forget the limbers at the bottom chines of frames at stations 3 and 4!

With all of that set to cure, I turned my attention to the African mahogany for the transom.   It was rough, so I used my Mouse sander to obtain a medium-smooth finish, leaving some texture for gluing.  I then drew a center line on the mahogany and lifted the lines of the transom from the developed expanded transom lines on the lofting board.  Having the inside of the transom marked, using the table saw, I carefully cut away excess material leaving the lines.  Using RBC, I prepared the braces that I will glue to the inside of the transom.  The braces will start at the sheer line and go to the top of the keelson, thus providing more purchase for fastening the planking and the bottom and more strength.

Tomorrow, I will plane the sides of the transom to the inside lines, but will not plane in the bevels developed in the expanded transom.  I will glue the braces to the inside of the transom.  The planed inner edge of the transom will provide me with the line I have on the lofting board.  Once fastened to the keelson and in position on the strong back I will use those lines to plane narrower bevels aft into the mahogany of the transom and wider bevels forward into the RBC of the braces.

Part 1 – Part 2 – Part 3 – Part 4 – Part 5 – Part 6 – Part 7 – Part 8 – Part 9 – Part 10

Part 11 – Part 12 – Part 13 – Part 14 – Part 15 – Part 16 – Part 17 – Part 18 – Part 19

APPENDICES

4 Comments

  1. Am I the only one who doesn’t know what RBC stands for? I am thinking it stands for some type of cedar. Or maybe some type of wood we don’t have in these parts?

  2. Thanks John K. I missed that in the first episode. I usually check to see whatever is going on in Duckworks Magazine the first thing in the morning. It’s always interesting.

  3. The author here —
    Sorry about that acronym confusion. Using “RBC. throughout the document was sure easier that typing out “recycled Brazilian cherry” each time.

    I hope someone who is contemplating but hesitant about a first build can make some use of this document, if only to inspire some level of confidence. If I can build a boat, anybody can build a boat. That’s my take, and I’m stickin’ to it.

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