Work through 3/10/08:

Wooden hatches had to be used on the “Nereida.” Commercial, plastic/rubber hatches, although very water-tight, would have ruined the look. Wooden hatch systems can often leak so I’m using a system that’s given me good luck. The lids are cut from the deck and sit on molded carbon fiber and fiberglass lips. The lips are molded using the hatch lids themselves as forms. The hatches seal with 1/4″ thick closed-cell foam marine hatch cover tape. Not woosie hardware store weather stripping. In lieu of external straps the lids will be held on using internal bungees. The lids will also be tethered to the kayak with a length of 3mm cord. First let’s cut out the hatches…

I went with nice, big oval hatches for the “Nereida.” They seal better than ones with straight sides. They’re similar in size to the commercial ones. The fore one is about 12″ x 8″ (30 x 20 cm), while the aft is about 16″ x 10″ (40.5 x 25 cm). I drew them directly on the deck by hot gluing a piece of scrap wood with two brads in it spaced at the origins. A magic-marker then follows the outside of length of rope. It’s the classical way to layout an oval. I made a slot for the jig saw by I drilling some 1/16″ (1.5mm) spaced very closely together in the middle of the layout lines. After cutting out the lids I sanded the lids to one edge of the magic marker and the deck openings to the other. The thickness of the marker works well the gap between the lid and the deck. I made some finger slots/drains in the deck with a sanding drum and then rounded over the edges slightly. Any bare wood was then coated with two coats of epoxy. I used the thicker FLAG resin and fast hardener.

After the epoxy had cured I taped the inside of each lid completely. The packing tape will act as a form release after I laminate the lids. Usually at this point the lids are taped back to the deck and the lips are laminated on to the inside. Epoxy usually flows into the crack between the deck and the lids and causes problems. Now I decided to try something different. I taped the lids to the INSIDE and drizzled in some paraffin wax into the crack from the outside. I used the Swix iron I use for waxing my x-country skis. Set on a low temp and lightly rust rub a block of wax against it. Let the drops fall into the crack and fill it completely. When cold I taped the outside with masking tape and removed the inner tape. Now I can laminate the lip without any worries of the epoxy filling the crack. It’s already filled! The wax is weak and (should) break out easily.

The laminating schedule for the lips is pretty simple: one layer of 4-oz E cloth that will protect the carbon fiber, a layer of 5.5 oz plain weave carbon fiber and then 4 layers of 6-oz e glass. The total thickness is about an 1/8″ (3mm). TO cut down on later sanding and to suck up some of the extra resin I used a final layer of peelply. I rolled it on using a toothed fiberglass roller to really press the layers of cloth down and then squeegeed off any extra.

When the lips had cured overnight I gave a shot at separating the lids from the lips. I cut away any extra cloth on the lip and then inserted a small, tapered, plastic squeegee in between the lid and the lip and gently pried them apart. Worked great. Most of the wax stayed on the lip so I scraped off what I could using a plastic scraper usually used for waxing skis. I then marked off the width of the lip (3/4″ = 1.9 cm), cut it with a jig saw and sanded the edge smooth.

At a later date I’ll sand the lip smooth and make and attach the hardware for the bungees and tethers. The 3rd day hatch is being handled a bit differently than the main hatches. I’ll post a separate entry for it later.