Fly Fishing Traditions

Fly Fishing Traditions Blog and Website
"It's about Life & Fly Fishing"

Tuesday, October 14, 2014

Kingfisher Drift Boat Build - Aft Knee Braces - Design Process

First I'l catch up a little with an update - I've got my dry boxes installed on both sides. This entailed using 5 minute epoxy to attach the front and two sides of each dry box  to the bottom and sides. The 5 minute epoxy was used in spots just to hold the pieces in place. Once they set, I mixed up some epoxy peanut butter, pretty darn thick and used it to fillet the pieces in place. The fillets form a cove that is a transition from horizontal to roughly vertical (floor to sides). Once the fillets are installed 4" glass tape is applied over them and then flow coated. A lot of busy work. It took a full day to get it done, and I mean a long day. That doesn't include the sanding once it's set up.

The photo above  is the aft pedestal in one of Jason Cajune's boats.

My next task of choice, not necessarily in the right order was to make a decision how to construct the aft knee brace. I like the idea of the flow through interior. I want to be able to get from the bow to the transom without crawling over a knee brace. I've decided to do a knee brace similar to the one that Jason Cajune does in his "Recurve" boat. The problem is, it ain't easy by any means. The one I'm constructing will look something like the photo above. I first thought they were a little too "George Jetson" for my taste. But as I've explored my options I've decided the Jetson's were cool.. There aren't any plans or instructions how to do this so I'll have to just dead reckon my way through it. I'm pretty good at that.

The reason I'm working on them now is that they attach somehow to the aft level floor step and are partially painted with the same material as the floor. So I've got to be able to;

(a) Figure out how to construct the darn thing.
(b) Figure out how to attach it
(c) Decide if it's permanent or removable
(d) Get it done or figured out before I paint the floors and the lower part of the sides and dry boxes.

Solving the Construction of the Aft Knee Brace

The knee brace is constructed by laminating 3 layers of 3mm Okoume plywood in what amounts to sort of a "Question Mark" shape. Pretty appropriate when you have no idea what you're doing. It will end up about 7/16" thick and glued together with thickened epoxy. I started out by cutting some different shapes out of scrap plywood to see what shape seemed "right". 

Here's a photo of one of the "Question Mark"s I cut out to see what it might look like. This one was too deep of a bend I thought. I cut  different shapes until I got one that seemed right. For me it's just sort of a trial thing. Try different curves until I thought "That's it". I'm shooting for a height of 27" above the aft level floor.

Once I determined the shape, I needed to construct a form to bend the plywood to the desired shape. I laid out the "Question Mark" on a 1/2" sheet of plywood and made to opposing pieces that will mate together with a 7/16" gap between them (the thickness of the laminated plywood). In the photo above you can see the 7/16" strip that is being cut out. I had to make two each in order to make a form that was approximately 24" wide.

Here's the forms assembled. I will be bending 3 pieces of plywood that are 24" wide by 48" long. All I have to do now is figure out how to get the 1/8" Okoume plywood to bend to the shape. Another "Question".

Next Up Steaming and Bending 1/8" Okoume Plywood 

A forewarning, It ain't Easy!

No comments:

Post a Comment

Have any Questions or Comments? Let me know, Clay.