SHOP: kayak mods_ retrofitting a ruddered kayak with a skeg

My SeaBird Designs kayak came with a rudder.
While probably a faster proposition for the racer a rudder in my opinion hinders good sea kayaks. I have paddled the kayak for a while now and always with its rudder stored on deck. The kayak does weathercock slightly.
In winds of 15 knots or stronger some effort is needed to edge the boat and use corrective strokes to keep it from turning into the wind.
The rudder has been removed and I have embarked into the daunting task of fabricating my own adjustable skeg.
Pricing a ready made kit from a local kayak manufacturer made me think that I can probably make a better one possibly cheaper.
Greg Schwarz has been my inspiration and his work is truly outstanding and after some consultation with him I decided that it must be done.

The trickiest part was sourcing high quality housing for the stainless steel wire/cable needed to adjust the skeg.
I found what I needed at an industrial hose supplier. The exact product is a high density polyethylene hose used for compressed air. The fitting for the hose is brass and has a neat "olive" to securely attach the hose to the skeg box.
The next step was to decide what shape and what size I wanted my skeg.

The skeg does not need to be very large and a sloped triangular one was going to be the least obtrusive one inside the rear hatch. I cut a piece of "smoke" colored 5 mm tick polycarbonate (Lexan®) to the slightly oversized shape of my desired skeg. Note the slightly oversized; we will come back to that later.

I waxed up the skeg with mould release wax and placed it on a smooth flat surface. Mixed up some epoxy and tinted it with black die: I don't like the look of semi transparent fiberglass. I used 2 layers of double bias cloth (available at most marine chandleries) and draped it neatly over the skeg.

top half ready, bottom is freshly laid
Once the resin hardened enough (10 hrs approx) I trimmed the excess cloth away with scissors and left a flange of about 2 cm. I repeated the same operation by flipping the skeg and making the second half of the skeg box. The two sides were flat and matched well.

I roughed up the flange surface with coarse sandpaper to create a good mechanical bond. This time I mixed up some epoxy (tinted again with black) and some microfibre filler (extender) to create a thicker glue that would not run. I joined the two skeg box halves allowing for a slightly wider gap at the bottom/entrance of the box to create a slight taper.

the two halves are joined

the bottom of the box was separated slightly to create a taper
The joint was filleted with the tick epoxy paste to create a strong joint line.
Once the joint cured the excess fibreglass flange was cut away and the ridge line made smooth with sandpaper.
A slot was cut to accomodate the brass housing fitting.
The fitting was fibreglassed into the slot with epoxy paste.

slot cut into skeg box

fitting before fibreglassing

fitting with fibreglas and resin

The skeg pivots on a stainless steel 5mm bolt secured with epoxy in the skeg box. A washers was cut out of nylon (or polyethylene) for each side of the skeg to prevent friction between blade and box.

cutting the washer

washers in place, excess bolt still to be cut

A slot was cut into the skeg blade to allow the skeg to be attached/removed without undoing the bolt.

The skeg wire was attached directly to the polycarbonate blade. A hole was drilled into the blade, a slot cut for the cable, the cable end was frayed a bit to ensure a better grip for the resin.The cable was resined in with epoxy paste and a laid on baking paper to create a smooth surface. The excess resin was trimmed once cured.

cable before resin

resin before baking paper

skeg dimensions (in mm, sorry metric only) click on image for larger view

The skeg is controlled by a stainless steel wire.
A control box with a knob attached to the wire was fabricated.
I used a piece of PVC conduit to shape a plug for my control box.
I cut the PVC pipe in half and after heating it gently on a flame I pushed it into a “U” shaped section.

I used West System 105 resin, 207 hardener (UV stabilized) to impregnate some carbon weave cloth.
Draped the resin rich cloth over my plug and overlaid it with cling wrap (Glad Wrap®) to prevent it sticking to the two blocks of wood keeping close shape to the sides of the cloth/plug.The box once cured needed end “walls”. I cut a small section of plastic and used it to “dam” the ends.

control box with ends in place

A section of the deck had to be cut out to have the control box recessed flush with only the knob slightly protruding.

Would you believe that after all that careful measurement and attention I cut and installed the skeg control box in the wrong position?

I took great care to make sure it will be out of my legs and knees' way but forgot to allow for the cable that would protrude past the box.

And of all places I did align it perfectly with one of the deck fittings.

The cable would run into the fitting!

After much cursing (you can imagine) I had to cut out the carbon box, clean up the resin and repair the massive hole left by the box. A new box was fabricated and repositioned.

The deck was repaired (I kept the section of deck that was cut out) and the gap left by the cutting blade filled with color matched gel coat.

skeg control knob (slider)

The control knob was fabricated from a piece of clear polycarbonate.

The knob was shaped to fit neatly inside the box and a hole drilled at the base to allow the sleeve to fit through.

The sleeve is drilled to allow a bolt (or grub screw) pinch the cable and keep it in the desired position.

The whole assembly has to run smooth and care must be taken to ensure that there are no bends where the sleeve runs inside the housing or a jam will occur.

control knob secured onto the brass sleeve.

The skeg cable runs inside the housing until it reaches the control box.

Here it enters a stiffer tube (stainless steel is desirable, brass will do) that would act as a sleeve.

The sleeve has to fit tightly around the cable and still be able to fit inside the polyethylene housing. The stainless steel cable is never exposed and therefore the chance of kinking the cable is reduced.

gel coat repair still to be sanded and buffed

skeg box view inside under the deck

It was time to assemble the skeg blade into the box.
You should end up with the blade well inside the box allowing trimming for the hull thickness and curve of stern keel line.

Once I had my parts ready it was time to prepare the hull for cutting.
This is the most critical part.
Measure twice, cut once! (yeah right...:-)
A perfect centre line is needed along the keel.
I selected and area as close as possible to the stern of the kayak but not too far for being able to reach from the hole of the rear hatch. I would need to work through that hole and be able to glass the skeg into place!
I masked the area with masking tape and draw lines on it to have a very visible cutting line.

masking and marking

checking for gap width

Once I was positively sure that all was good I fired up the Dremel®.
You will need a high speed cut off wheel. Wear a mask and goggles.
I cut less than needed and enlarged the hole slightly as required to fit the skeg box.
I managed to cut away a very tight fit and my skeg box had a gap of only 1 mm in places.

the scary part

The box fitted well and with the blade in place I made sure it would not protrude once trimmed.

skeg box before glassing

The skeg box was then perfectly aligned vertically in the kayak
A spirit level helps.
I removed the skeg blade and inserted a piece of wood the width of the box protruding about ½ meter.
I used that to align the skeg box.
The skeg box was then glassed into place with epoxy paste first (to create a watertight seal) and fiberglass tape later for strength.
Once cured I trimmed off the excess of the skeg box. A flush finish is desirable.

I masked a small frame around the box, sanded it and applied some West System 105/207 epoxy since my hull is clear and I wanted to have a non visible joint line. I did two applications for wear abrasion.

skeg blade retracted

pivot point

the skeg fully extended

skeg box view inside hull

housing attached to skeg box.

Loop/guard of fibreglass to prevent damage to housing when loading kayak with camping equipment

I hope I have not bored you with my account of retrofitting a kayak with a skeg.

I also hope that I have not omitted something and made the instructions not clear enough.

Feel free to comment and I might try to amend/update the document.