Thursday, March 17, 2016
The large expanse of QUIDNON's deck (measuring close to 550 square feet) is interrupted by two masts stepped in mast tabernacles, a large hatch in the center of the deck, and the dodger and cockpit aft. These elements are quite traditional; but there are also two more elements that are somewhat peculiar: there are two deck arches. They bear resemblance to boom gallows, but they are much more than that. In keeping with QUIDNON's overall design philosophy, they fulfill as many different functions as possible, to save space and to minimize costs.
The two deck arches are made up of three joined box sections—two feet and the arch itself—cold-molded out of plywood and fiberglassed on the outside. A thick plywood baffle runs along the centerline of the entire structure, to give it strength and to separate the airflows on the two sides. Along the front and the back of the arch there are openings, which can be closed and secured shut using internal sliders. On the bottom of each arch, in the center, is an eyelet for connecting a hoist. Where the arch joins the feet, there are diagonal reinforcements. At the tops of the arches are perforated aluminum angles (not shown) which can be used to attach an awning.
The arches serve the following functions:
1. Provide a point of attachment for a hoist. The front arch is used to hoist objects in and out of the cabin through the large mid-deck hatch. The aft arch is used to lift the engine out of the engine well.
2. Provide attachment points for the hammock or a swinging bench. This is an additional function of the two diagonal reinforcements in the inside corners.
3. Provide attachment points for an awning. The upper edges of the arches carry perforated aluminum angles.
4. Provide ventilation for the cabin. Front and rear sides of both arches have openings that let air either in or out, depending on wind direction. A baffle along the centerline of each arch keeps the two airflows separate until they reach the cabin, where they terminate in vents that direct the airflows in different directions, blowing air in and also sucking it out. They provide plenty of ventilation at anchor and on all points of sail except a beam reach. When sailing a beam reach in relatively calm conditions, the mid-deck hatch can be cracked on one side to cool the cabin.
5. Provide extra buoyancy up top in case of a capsize. The air openings on the front and back of each arch can be closed and secured using sliders, to create an airtight structure above deck level. Each arch encapsulates around 15 cubic feet of air. Both arches add around 2 tons of positive buoyancy 4 feet above deck level. This is very useful in case of a capsize, and enough to prevent QUIDNON, with its large, flat deck, from wallowing upside-down for any length of time.
6. Provide attachment points for sheet blocks (on top of each arch). A known problem with junk sails is that with most sheeting arrangements the sail tends to twist, losing efficiency, especially to windward. What typically happens is shown on the left; the optimal arrangement is what's shown on the right.
But in many cases this doesn't matter. For those who want to use QUIDNON primarily as a houseboat and prefer to keep things simple, a very simple sheeting arrangement will work fine, with a set of blocks mounted on top of each deck arch, while those who will want to make long passages to windward and would like an extra bit of speed can add a euphroe. I am also playing around with ideas for the ultimate solution: an automatic sheet traveler, but haven't tested it out yet. Here it is, shown schematically—not drawn to scale, and the final design will use tracks, sliders and blocks rather than rods and rings. But if you think hard enough, you should be able to puzzle out how it's supposed to work.
7. Provide places to mount navigation lights, red/green on the sides of the front arch, white aft light in the center, on the back of the rear arch.
8. Serve as boom gallows. When the sails are down, they can be made to rest on top of the arches.
9. Provide a support structure for the masts when they are down, for motoring down canals.
10. Provide an elevated place to sit or stand, to see a bit farther on the horizon and to be able to read the water better when sailing through shallows.
General progress update: There is now a full 3D model with most of the features drawn to scale, done in Sketchup. It has been moved to make a model in Delftship, which will be used for various calculations, and is in the process of being imported into SolidWorks, for creating a 1:12 scale model. There are plans to set up the model with radio control and sails, and to see how well QUIDNON sails.