Cockpit deck beams

Moving the cockpit forward means I have to redo the two deck beams that form the front and back of the cockpit, I've already diverged from Brink's plans somewhat.  Let's customize this a bit further.

The deck beam I took out was a bit fragile - it broke when I was taking it out. It was under a reasonably amount of stress, but still, I want to lean back with confidence.  So I will make the backrest more robust.

More interesting though, modern sea kayaks have thigh braces so you can lock yourself to the boat for control when you roll.  Baidarkas are high inside and there's no good leverage for rolling.  I have those unused mortises in the gunwales right in the middle of the cockpit side, where a thigh brace would start.  I could shape the cockpit-front deck beam with places to connect the front end of the brace.  Let's make the forward deck beam "brace-ready"!

The old deck beams were made for 2x4 lumber, but these needed to be heavier so I bought a lovely cedar 2x6.



The lines are a bit faint in the photo, but you can see that the center section is the critical width needed to slide my legs in (as measured when I put the boat on the floor and measured for fit!).  The side pillar sections will anchor the thigh braces.



Yay for narrow band-saw blades.  This would have taken forever by hand!



The plane made short work of the saw marks on the outside and the spokeshave cleaned up the inside, followed by rounding the edges with sandpaper.

The tenons are interesting to cut because the sides of the boat narrow toward the ends so the beams aren't cut square across.



The first thing is to use a sliding T-bevel to get that angle.

  

But how to hold the square against the wood when I've cut it away?  Luckily I have a piece that neatly fills that hole!

   

The next trick is to very carefully cut on the line - WITHOUT cutting down into the tenon.  A nice hack is to put a piece of wood on the far side at the height of the line.  Then I can watch how close I am on this side and cut down till it touches the block of wood on the far side.  Voila!  Perfect cut!  Note that the tenon itself I could cut on the band saw.

  

A quick floor test - the width of the arched space is perfect for sliding my legs in (with room for clothing) and the brace supports are at the right height for bracing!  However, the edge of the underside of the curve was a bit sharp against my shins sliding in.  Need to angle the underside of the curve up a bit.









Propping the beam up on piece of wood holds it at an angle so that the bandsaw cut is at just the right slope to make sliding under the curve comfortable.



There we are!  The cockpit beams are in place!  Next up, thigh braces and cockpit coaming.

Moving the cockpit deck beams

The holidays and the start of skiing season put a huge dent in my boat-building time.  I've been getting little bits done here and there however - my current completion target is February.  (Frustratingly enough, we're having an unusual January thaw and the local rivers are clear - if I'd finished up already, I could be paddling now!).

So, the float test indicated that the cockpit needed to move.  But not all the way to the next space between deck beams, sigh.  That means taking the beam at the front of the cockpit out and putting in two new ones half-way between the existing ones.

Of course, since I pegged the beam, the first step is to pull the pegs.



Simple enough - drill a hole in the center of the center of the peg, twist a screw into the hole, and use vice-grips to work the peg out.  The gunwales are flexible and spread just enough to get the deck beam tenon out.

Now I have one last chance to recheck the dimensions of the cockpit.  I put the boat on the floor and do another mock-up of the position of the front and back of the cockpit.



The plank is at the height of the back of the cockpit (where I will sit when sliding in).  The underside of the gray bar is at the height of the underside of the forward deck beam.  Yes, I can slide in, even with shoes on.

The vertical 4x4s are the width I need for my hips (including a bit of space for clothes).  This gives me final positions for the deck beams and it gives me the coaming dimensions both forward-back and side-to-side.



Now that I am sure where the new deck beams will go, it's time to cut new mortises.  But the boat is too long for where the bench was - so I had to get the mover's dolly to slide it down far enough that the mortise positions are on the bench.



Hmm, last time I put guides on both sides of my router so it would cut in just the right place.  But there are ribs on one side now.



So, a block on only one side, exactly 1/2 inch from the cutter.  And I'll have to be very careful to hold the guide against the gunwale!!!



A quick test - yes, perfect.  The ruler is at the 2nd test hole.  The closer hole was my first try - I didn't hold the guide tight against the edge and the router wandered, making a wavy slot.  Y'know, with software you can make a back-up copy before making tricky changes.  If I screw this up, the whole boat's toast.  No pressure.



The clamps set the limits of the hole.  I've roughed out the first deck beam to check the hole width.



Here goes!



The last step is squaring the ends of the mortise with chisels.  One end done, one to go.

I cut the mortises on one side and then went to turn the boat around.  Hmm, now that the bow and stern are attached, if I poke the bow into the bottom corner of the basement  and tip the boat at an angle I can just swing the stern just past the lally column where it holds up the ceiling.  If the boat was an inch longer I'd have had to trim the bill off the duck on the bow!

The next step will be to make the two replacement deck beams and lash everything in place.

In the mean time, I've started on the cockpit coaming.  It will be 1 1/2 inches high and half an inch thick.  I want to make it out of that nice green oak, but I need more than 12 feet to wrap around my 2 foot cockpit (circumference of a circle is pi * diameter - this is oblong so will be a bit less, but I need extra to overlap for the joint).  The log is only 5 feet long so I'm going to build the coaming up from multiple 1/4 inch strips.

I've used up the oak I cut for the ribs, so I need a new slab.  Luckily we had a warm spell and the snow melted off.



Cutting straight lines by eye is tricky.  If I were going to cut many more slabs I can see the advantages of getting a chain-saw mill.  I'd need a longer chain saw though - this is just a 1/4 pie slice of the log!



The jointer is really handy.  I used it to squared up one edge of the rough board,  Then took the board to the band saw and trimmed it to six inches wide (the width of the jointer blade).  Then back to the jointer to get a flat side.

Next, a bunch of passes through the planer made it into a pretty 1 1/2 inch thick board!  Have to admit, the jointer and planer are so much faster and easier than a hand plane - and produce a gorgeous square flat result.



Next was to cut four 1/4 inch strips.  The carbide blade on my table saw has lasted for more than 20 years - but cutting through the 1 1/2 inch green oak did it in.


The dull blade heated up and started to burn as it cut.  Even with two windows open and two fans running the basement filled with smoke (setting off the smoke alarm).  I guess it's time to replace the blade!

Next step on the coaming will be to make scarf joints to connect the ends of the strips, to cut an oval plywood form to shape the coaming around, and glue it up.

It's getting to where I can see the end of this project!