John's Cirrus LT with Strip Deck

 

Contents
Page 1:  Cutting and Gluing Panels (You're here now!)
Page 2:  Fiberglassing
Page 3:  The Finished Kayak

I am building a Cirrus LT kayak.   It is 16 feet long, 21.5 inches wide, with a waterline width of 19.2 inches.  It has an optimal load (kayaker and gear) of between 130 and 187 pounds.  The Cirrus LT was designed by Vaclav Stejskal of One Ocean Kayaks.  

I chose this design because I wanted a hard chine kayak to play in.  This is my winter project.  

From the designer's website.Cirrus LT Side View
The image above (from the designer's website) shows the profile of this design.  I especially like the outward flare of the side panels, which should provide good secondary stability with a relatively narrow waterline width.

Full-lengh panels before cutting ensures proper alignment.My 4mm Okoume plywood was purchased locally at Plywood and Door in Dallas, Texas.  It is stamped "BS1088" and has a "Lloyds Approved" sticker on it, but the exterior plies are barely more than veneer thickness so I had to be careful making scarf joints so that no interior wood appears.  

The plywood was 250 cm long (98.5 inches) so the hull panels fit nicely with only one scarf joint.  The plywood was ripped and joined to form two long sheets, 2 feet wide by 16.3 feet long.
 

Wiring holes drilledThe paper hull panel templates were taped to the plywood sheet.  They were aligned using a string to mark a perfectly straight line.

With one plywood sheet clamped on top of the other, the wiring holes were cut through both sheets simultaneously, before cutting out the panels.  These wiring holes provide plenty of points to secure the two plywood sheets together when cutting the panels.  At least any cutting imperfection will be symmetrical!

Per instructions, I cut along the panel perimeter into the wood with a sharp utility knife.  After removing the paper I cut both plywood sheets at the same time.  My wavy jig saw cut was approximately 1/16" outside the knife-marked panel edges.

StrongbackStrongbackThere was too much stooping over to continue working on the floor, so at this point I decided to build the strongback table.  My table was made from one 4'x8' sheet of 3/4" thick plywood in a 'T' formation.  The table top is 12" wide by 14' long, with a 7" tall vertical support running the entire length.    

The strongback was attached to kayak cradles that I had used for other kayak projects.

Fairing_panels.jpg (272939 bytes)Symmetry is important in kayaks!My jig sawing skills aren't very good, so my next step was to fair the panel edges to the knife line.  I used a belt sander, fairing board and block sander with 60 grit paper.

The two panels were perfectly positioned relative to each other using small nails through the wiring holes (photo at right). 

The inside edges between the panels were rounded or beveled a little so the panel edges would fit closer together.

The mold forms were cut from 5/8" fiberboard and 3/8" plywood scraps.  The paper templates were glued to the wood with spray contact cement, then cut with a jig saw and refined with a belt sander.  My kayak will have a wood strip deck, so the deck forms that were intended for for plywood panels were modified  rounded.   

StitchingStitchedThe most exciting day in the building process for a stitch and glue kayak is when the hull panels are wired together to unveil the shape of the kayak.  I just had to sit down and admire it for a while.
    

Epoxy-tabbed hullAfter carefully aligning the panels, tightening wires, and checking alignment again and again from every angle, the panels were fused together using silica-thickened epoxy.  Small dabs of epoxy were applied on the seams between the wires using a plastic freezer bag to squeeze out the epoxy like cake icing.  The epoxy was smeared into the seams.

Later, the wires will be removed and the joints properly filleted.

The construction order of this hybrid stitch & glue and strip kayak is somewhat different than my earlier kayaks.  Now that the hull is fused in shape, the next steps are:

Fairing and sanding is next.For the deck, I am using strips left from earlier kayak projects, so my color choices are somewhat limited.  This boat will have a simple two-color symmetrical deck design,  with the inner color forming something like a fish outline, with a split tail. 

Ready to fiberglassA sealer coat goes on firstThe deck is stripped, faired and sanded now.  I used a fairing board with 60 grit, followed by 100 grit on a random orbital sander.



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Created December 25, 2004