Carbon Fiber Layup On Coaming

The cockpit rims on these boats are being finished with a carbon fiber layup. The fabric is 5.5oz twill weave from U.S. Composites. I cut an oversized piece and laid it over the coaming and cockpit opening, gently smoothing the wrinkles and puckers by hand.

After I was satisfied with the way the fabric was laying I poured a generous amount of unthickened epoxy around the rim. I worked the epoxy into the carbon fiber using a plastic squeegee and a disposable chip brush. The squeegee was used to hold the fabric from sliding while I pushed and dabbed with the brush to work the epoxy into the fabric.

Once the fabric was thoroughly saturated I laid pieces of fiberglass cloth over top of the carbon fiber and wet out the fiberglass with more epoxy. I read so many posts on the forum warning that carbon fiber should be covered in fiberglass to help contain sharp splinters and shards in case it shattered, that I became convinced it was just a ticking timebomb ready to explode at any moment and shower any unsuspecting bystanders with "Carbon Fiber Shrapnel".

Coping With The Coaming

Plastic sheeting separates the laminations from the deck

The coaming is assembled from layers of plywood, laminated together. Reading the manual and picturing the assembly I could see this was going to be one of the more challenging tasks in building these boats. I again referred to Laszlo's wood duck blog, and the technique he illustrated for assembling and installing a laminated cockpit rim seemed much easier.
Laszlo recommends putting plastic sheeting on the deck around the cockpit opening and using the boat as a jig to glue up the pieces of the coaming. The pieces will form to the proper shape to mate to the deck, but the plastic stops them from adhering to the boat. Once the epoxy cures, the whole coaming assembly can be removed, allowing easy access to all sides for sanding and shaping.  Once all the rough (very rough) edges have been smoothed the coaming can be epoxied in place on the deck. When I used this method I only had to be concerned with cleaning up the squeezed out epoxy from one glue joint, not several.

The inside rim of the cockpit rim is easily sanded

Once shaped the rim is epoxied to the deck

Very little squeezed out epoxy to deal with using this method

Deck Glassing Part II

Fiberglassing the deck was significantly easier than fiberglassing the hull. The fabric was lighter and wet out easier, and the flatter surface kept runaway epoxy to a minimum. The glass drapes over the side of the boat and overlaps the hull by an inch. I followed the technique illustrated on this blog by Laszlo, as he builds a Wood Duck kayak. Two inch wide clear packing tape is applied to the hull one inch below the edge of the deck. The fiberglass cloth is wet out, applied to the deck, and wrapped around the sheer and applied up to the tape.

 Before the epoxy reaches full cure you gently pull the fabric away from the tape and cut/tear the cloth at the edge of the tape. Despite removing the packaging tape immediately after cutting the excess away I was still left with a lot of adhesive residue from the packing tape. I switched to blue painter's tape and did not have the same problem.

Blue painter's tape defines the edge for cutting away excess cloth

Rice paper logo graphic under fiberglass

Glassing the Deck

Sample rice paper graphic on scrap plywood

With the decks installed, preparations are made for fiberglassing the deck. "Preparations" almost always means sanding. In this case, there is much sanding, as well as the opportunity to personalize the boats. Pictured to the right is the logo created for the builds. This image is printed on rice paper with a laser printer and epoxied onto the wood under the fiberglass. The epoxy wets out the rice paper and it becomes mostly clear, and the fiberglass coat protects it from damage.  The logo will be applied to the rear of the deck, and I will also apply a compass rose graphic to the front of the deck, again using the printed rice paper method.

carbon fiber accent disguises forward deck scarf joint

In addition to the graphics these boats will have a carbon fiber accent piece on the nose. My preferred finish for the kayaks is a painted hull and a varnished deck. I don't want to say this too loudly, but I am not a fan of the all varnished finish. I like the way the polyurethane painted hulls resemble gelcoat, I also like that the painted hulls cover the scarf joints on the hull panels. My idea to disguise the scarf joint on the forward section of the deck is to epoxy down a triangular piece of carbon twill cloth. I laid a piece of fiberglass tape crosswise on the transition from cloth to bare wood to help feather it in without sanding into the carbon fiber.

Carbon fiber feathered into bare wood. A painted stripe will cover the transition.

Decking

Tie-down straps secure deck in place for nailing

Full sheets of plywood are laid on the hull and traced to the shape. Each piece is rough cut to size and secured down with straps. A marking jig is used to draw a line on the top of the deck for nail placement. Care is taken to place nails in the center of the sheer clamps.

The underside of the deck is coated with unthickened epoxy to seal it. The sheer clamps are coated with thickened epoxy, and the deck is positioned, stern section first.

The front section of deck is two pieces epoxied together with a scarf joint

The deck was nailed in position with bronze ring nails approximately four inches on center. The nails are redundant once the thickened epoxy cures. I debated not using the nails, but I could see the whole process going sideways without them.

Once the deck was securely attached, I used a jigsaw to trim close to the sheer, and finished with the block plane.

The glued and nailed deck is trimmed to the sheer

Prepping For The Deck Installation

Sheer clamps are planed to match the deck angles

Prior to attaching the decks a few items need to be completed while I still had full access to the inside of the hull. Many builders do the epoxy endpours after the deck is on, the manual's recommended approach is to dam up the ends and fill with epoxy.

Carbon Fiber tape epoxied to inside of hull for foot brace mounting

Kayak ends are filled with epoxy for strength

Installing Deck Beams

Jig for laminating deck beams

Both the Chesapeake 16lt and the Chesapeake 17lt require a pair of curved deck beams. A large one just forward of the cockpit opening, and a smaller one set near the bow. The larger of the two beams was made by laminating layers of 4mm plywood together on a jig. The smaller forward beam was cut directly from a piece of 1x4 pine.  With more forethought I would have made the laminated deck beam pieces longer and cut both beams from a single curved piece.

The directions call for attaching the deck beam with thickened epoxy and a single screw through each sheer into the beam. Like many builders on the CLC Forum, I opted to only use

Laminated deck beam is cleaned up and the sharp corners eased

the thickened epoxy and reinforce the deck beam with epoxy fillets. My thinking is that once the deck is securely attached to the deck beam and the sheer clamps the deck beams will be locked into position.

Deck beam clamped in position