New project: a smaller kayak

 Having just completed a large kayak with ample storage space, it weighed in at sixty pounds, which is too much for my wife.  But the basic design looks good, now I plan to create a slightly smaller version of the same exact design.  Frames will be spaced at 13.5" instead of 15" and the depth is reduced by 2.5".  I wonder how different the hull will be visually.  Progress will be slow because of the holidays, tax prep, and a long-planned trip.  Design dimensions are 153" by 26.6".

 A hint of what is to come:  The deck beams are laminated.  They all have the same curvature; thus, they could all be built on the same form.  The remaining parts of the frames are built from individual pieces that are half-lapped and then bonded together.  The plank that all the frames are resting on will be the future keel.  That keel will have a slight rocker by design.  My strongback, such as it is, consists of a ten-foot long 2X6 resting on two sawhorses.

Kayak frame completed.  After I have the bottom and topsides planked, then I will alter the deck beams to create a cockpit.

1) The offsets for all frames were mathematically calculated.  The shape of the plank keel and the bow entry & stern were also calculated.  The total length of the sheer and length at each frame connection, also calculated mathematically.  

2) Full size drawings of frames, bow & stern, and keel ends were drawn.  Most data points are only a few inches apart.

3)  Individual pieces were constructed from those drawings.  Midlines were marked on each frame for visual reference during assembly.

4)  Given that three points define a plane, each frame can only fit in one position defined by the keel and port & starboard sheer connections.  At bow and stern, additional rigid triangles are created by the bow, keel, and port & starboard sheer connections at the adjacent frames. This forces the port & starboard sheers to meet in a predetermined fixed relation.

5)  With epoxy and plenty of clamps, all connections only fit in one position, allowing assembly without use of a strongback form.  Planking can now proceed on this rigid underlying total frame.

Now I have started planking the hull.  With natural wood, each plank has to be considered individually.  Few are absolutely straight.  None are the 14+ feet long needed; thus, each requires a scarf joint.  I ran them all through a planer to get uniform thickness.  The initial planks all are positioned in the 1st projection of the hull form, meaning they all lie in one plane and can be laid straight without any taper.

But this is a triple chine hull (four projections); at the turn of the bilge, angles change several times, and intersection of planes required that planks located at the turn of the bilge be tapered and less than full length.  The taper was determined by clamping the future plank in place and then tracing the overlap from the inside of the hull as a guide for trimming.

No fasteners used; tomorrow I will bond this partial length plank in place with epoxy and plenty of clamps.  Instead of spiling, I clamped the proposed new 1.5" wide plank in place and then traced (inside the hull) with a pencil the overlap between the new plank and previous plank. This guidance was then used to trim the new plank to its tapered form.    

No strongback or forms used.  The plank keel, frames, and stems create a solid skeleton to build on.

Planking of the hull is complete except for finishing.  Next, I will concentrate on cleaning up the interior and finishing it.  Other tasks to consider are the sanding and filling of the hull exterior and planning the cockpit and decking.  Still, this is a nice milestone of completion where it really looks like a boat.

Three coats of varnish on the interior.  The exterior has been sand/fill/sand with a flowable epoxy paste. Now I am creating a contrasting pattern of decking planks.  The color difference will be enhanced when I start varnishing.  The darker planks are select alder wood.  Alder is normally known for its knots; this is select alder; no knots, but still there are variations in the grain structure which cause slight curves in these planks.  In a ten-foot plank, you may find 2-3 slight curves.

When you are laying multiple adjacent planks, you can't allow gaps due to this waviness.  Thus, each plank needs to be fitted to its position, slowing the process.

Finished planking the deck and fitting the cockpit edging.  Now it will be more filling any flaws and more sanding of the deck.  Then paint and varnish.

Paint and varnish added.  I am using all Epifanes products and am pleased with the results.  The seat is being varnished separately.  Now I need to get a light trailer to carry either two kayaks or a single rowboat.  Colorado has few lakes, and many are at altitude where they are covered by ice for almost half the year.  Most marine products I use need to be mail ordered.  But the low humidity is excellent for boat building.