Thursday, March 13, 2025

Putting the Pieces Together

Keel and frames temporarily clamped together, the start of a new kayak.

 For all of my earliest boat-building projects, I used plywood sheathing.  For recent builds, I have used no plywood.  Part of the reason is due to the type of boats I have recently taken an interest in.  Smaller boats tend to have sharper curvatures requiring narrower panels for sheathing:  Why not just use solid wood for these narrow panels?  When you sand solid wood, there is no concern about sanding through one of the plywood layers.

Using solid wood for the frames does require more joining of narrow boards, but it also provides better strength by aligning all the wood grain in the proper direction.  I use epoxy adhesive except for the laminated deck beams; there I use Titebond III.  In bonding the multiple layers of the curved beams, you expect to get 'squeeze-out' to ensure complete bonding.  Epoxy is messy and hard to clean up in such situations.  I have been using Titebond in limited applications for many years with no failures.  These underdeck beams will not be exposed to much moisture.

Next step is to create the stems for this hull.  I usually start with 2"X4" lumber for these pieces.  I want plenty of bonding area where everything ties together at the ends of the hull.


Creating the bow & stern stems will be my next project.

Stems are completed, ready to bond the sheer strip in place

All the pieces appear to be aligning quite nicely with no strongback required.

I used full deck beams for all frames.  That will allow me to size and place the cockpit wherever desired, although I already have decided except for details.  The stems look chunky now, but, when fairing, they will lose a lot of mass in beveling the ends.

All clamps removed.  We are looking at the framework from the stern.

With proper clamping, all pieces fit snuggly at the bow.  At this point, the hull is 158" x 25", but it will get bigger when the sheathing is complete.

I am adding one more longitudinal member to define the major chine, where the bottom and topsides come together.  It is not strictly required; the bottom is a single developable surface (beyond the keel), but the topsides consist of three separate projections blended together.

Bow stem prior to fairing.  Because the stems have a continuously changing bevel, it is best to fair the entrance angle after the piece is assembled into the frame.  I consider this step to be more sculpture than typical woodworking.  You have to do this in steps, frequently stopping and checking wood removal with a batten until it all blends together.

Bow stem after fairing.  The best tools for this are an angle grinder with 40-60 grit flap disc and a belt sander with a 60-grit belt.  I have a power plane, but it does not handle this 'sculpture' as well.  The exact bow taper is x/y/z = 14/3.6/1.

The stern stem is faired in the same way but with a slightly different angle due to its greater taper.  The next step was fairing together all the frame edges that make up the outside of the framework.  Routing a landing area at the edges of the plank keel, was the final step in preparation to start planking the hull.

Unfortunately, I was distracted, not focusing sufficiently, and gouged the keel in a couple of places when free handing the full-sized router used to make this rabbet.  The keel edge is curved near the ends (for about three feet) and the bevel is constantly changing, so 'free handing' is a requirement.  The router blade rotates clockwise.  If you pass the router from right to left along a board edge, the blade spins along that edge like a wheel, and things go smoothly with moderate wood removal and using multiple passes.  But, if you slide the router from left to right, the router tip can dig into the wood; you will not be able to hold it firmly enough, and a gouge results.  Why didn't I recognize that initially!  Yes, it is minor fixable, but still an impairment.

Now I start slicing planks.  Results will be delayed.  For the next 4-5 days, wet weather, including some snow, is predicted.  The cutting and planing produce ample sawdust which I would prefer to deal with outdoors.  My goal is for planks that will be 5.6 mm. (0.22") thick.

  




  

No comments: