XVIII. Finishing the Deck
Building the Core Sound 20
September 19, 2008
NOTE: This article is divided into chapters. Click here for the Table of Contents.
Finishing the deck is a lengthy process that must occur in conjunction with attaching the deck hardware. The deck cannot be varnished until all of the fastener holes for the deck hardware are drilled and epoxy-coated as described in the previous chapter; however, the hardware cannot be finally attached and bedded with sealant until the varnishing process is finished.
In our case, we began putting the finishing touches on our deck by attaching "hiking seats," which are 20" blocks of mahogany glued to the side decks to serve a dual purpose: (1) to raise the oarlocks so that the oars will not chafe or rub the coaming, and (2) to provide a place to sit while "hiking out" on the side rail to counterbalance the pressure on the sails. For the latter purpose, the seats make it more comfortable to sit outside the rail, preventing the coaming from pressing against the underside of your legs.
Next, we fashioned a bowsprit out of mahogany. The bowsprit is not needed to carry sail, but it provides an attractive visual counterbalance to the mahogany tiller on the stern and permits us to attach a bow roller for setting up a self-launching anchor. We made our bowsprit long enough to surround the forward mast step so that it would also deflect deck water away from the mast tube. Our mast tube is equipped with a drain, of course, but we still prefer to discourage water from entering the tube at all.
Third, in the process of attaching the deck hardware, we glued mahogany riser blocks outside the aft corners of the cockpit coaming so that the mizzen sheet could be run to the cockpit without interference from the coaming. The coaming is approximately 1" high, so we made the riser blocks 1/2" tall, which positions our mizzen sheet cam cleats just high enough to raise the spring-loaded jaws above the coaming. This allows for easy operation and ensures that any extra slack at the ends of the mizzen sheet can be coiled safely inside the cockpit.
After these pieces were attached and all of the fastener holes were drilled and sealed, we applied seven coats of Petit Z-Spar Flagship Varnish to protect the epoxy from UV degradation. We found it easiest to apply the varnish with special micro-pore foam rollers which yielded a nice, even coat that went on in a matter of minutes.
Technically, we were supposed to let each coat of varnish cure for 18 hours, sanding lightly before each new coat. To speed things along, we decided to reapply coats every 45 minutes, while the previous coat was still tacky and capable of providing a good bond without sanding. After three coats, we let it cure for a full day, sanded lightly with 220-grit, then applied three more coats in the same manner. Again, we let everything cure for a full day, sanded lightly with 220-grit, and applied the final coat. If you use this method, it is important to apply subsequent coats while the previous coat is still tacky. Unlike shellac, varnish does not contain solvents to reactivate previous coats, so a good bond between coats will not be achieved unless the coats are still chemically tacky or else cured enough to sand for a mechanical bond. Also, it is wise not to build more than three coats at a time without permitting a full 24-hour cure, or else you risk the possibility that underlying layers will never cure fully, resulting in a soft (less durable) coating.
After the varnish cured for two days, we were able to finish bedding and attaching the hardware as described in the previous chapter. At long last, launch day was upon us!
© 2008, Wesley Kisting