Stems

Internal stems are short pieces of wood that reinforce the bow and stern.  They are typically thin and narrow but they provide a great deal of structural support.  They’re not completely necessary and builders looking for a super light racing kayak may choose to leave them out.  Since I’m pretty sure I’ll be banging into stuff I’ll build mine with the stems.

They can be done a few ways but the most basic is to get a nice piece of wood about ½” thick and cut it into two strips that will fit the outer edge of the end forms.  It then needs to be tapered to a center point so the strips can be laid flush against it and glued in place.  The kit comes with a nice piece of cedar for the stems but unfortunately the supplier does not provide any information about what to do. 

The forms, a template and rough completed stem.

The end forms are about 20 inches long and protrude off of the ends of the strongback and the stems will need to be glued or taped to the edge.  With the forms you get thin, long pieces of particle board that serve as templates for the stems.  What I couldn’t figure out was how to put the stems on the forms and apply the strips.  Just using the stem templates on top of the forms made them protrude and that didn’t seem right. 

Without really thinking through the problem I decided to just cut the stems from the supplied cedar board and put it together.  Surely once the stems are in place it would make sense, right?  Nope.  I was wrong.  I spent four hours cutting and hand shaping the stems to fit on the outer edge of the forms.  When I had them complete I put them on the end forms but still couldn’t figure out why they didn’t look right.  I went to the computer to search the builder’s forum at CLC and I quickly found my answer.  I had neglected to cut room for the stems out of the end forms.  What a bone-headed mistake!

 

 Tracing the template onto cedar.

 

Note the two templates are cut slightly differently.  One for bow the other for stern.

The stem templates have a couple of uses.  They can be used as a template as I did or, if you are going stem-less, it can be used to mark taper lines on the end forms.  The templates are also used to trace a cut line on the end forms.  What I should have done was use the templates to mark the cut lines then use them to trace the stems onto the cedar.  Not researching the problem first resulted in wasted wood. 

 The original stem before hand shaping.

 

 The original stem after hand shaping.  Note the top edge of the form is uncut.

Original stem again.

I was unable reuse the stems because they had been shaped to fit the uncut forms.  There was enough left over to cut another stem but not two so I had to make a trip to the local hardware store for another board.  The cedar they had in stock was pretty knotty but I found some good looking aspen.  When I got back I immediately began removing the forms and accidentally broke them both.  I was able to re-glue the bow form without too much trouble but the stern form broke in two places.  The wider side broke in a difficult to repair spot and I still haven’t been able to get the glue to hold.

  

Tracing the templates on aspen.  Notice the ear form attached to the end form.  The one on

the stern form is keeping me from getting a solid enough clamp for the repair.

 

 

Stern form.  The narrow "leg" broke at the screw hole on both end forms.  This one also broke at the corner 

of the wide leg.  The repair is complicated because there is small form protruding from the backside.  

That prevents me from getting solid clamp pressure.

Not my best day but I did manage to get the bow form cut and a replacement stem shaped and ready.  I also was able to get the stern stem done but I can’t cut and reattach the form until I get it fixed.  When they’re done I’ll taper the stems and add a picture and brief description.

Rain?  Boooo!