Machine Design

Removing any inkling of Yngling doubt

Want to compete in the Yngling class in the next Olympics?

The first appearance of Yngling-class boats in the women's keelboat event was in the 2004 Olympics.

If so, you had better pay attention to your girth.

The 2004 Olympics marked the first appearance of the Yngling (pronounced "ing-ling") class boats in the women's keelboat event. The fiberglass hulls are 6.355 m long, have an iron keel for stability, and are rated to carry up to 500 lb. The design has earned a reputation for being quick, spirited, and versatile. Today, about 4,000 of them race in clubs around the world.

In competition, boats must be identical. Any modification to the shape of the hull is strictly prohibited. Each boat must conform to class rules for dimensions, weight, shape, and displacement. For the Olympic regatta, the attention to conformity begins at the trial stage. All hulls are measured to ensure they adhere to specifications. The problem is uniformity.

The curves of a keelboat are difficult to capture with conventional instruments, and 0.25 in. less girth could reduce drag enough to create an advantage.

Andrew Williams, founder of 3D Measure, uses the Faro Laser Tracker, a laserbased coordinate-measuring machine, to trace the Yngling hulls. The Tracker can measure large or distant objects (within a 230-ft range) to an accuracy of 0.0001 in. An operator first places the Tracker base on a tripod. Measurements are taken as the target reflector is guided along the surface. The device projects a beam that bounces back to the base unit. Software records the position of each point while simultaneously measuring two angles and the distance to the target. If the beam between the Tracker and target is interrupted, the device is smart enough to reacquire the beam without returning to a reference point. The sending/receiving unit can mount in any position and in almost any environment. The Tracker can be carried dockside to check a boat before it is launched.

It takes about 45 min to measure a boat. The critical points are center points on the hull, keel shape, keel depth, and specific girth sections. Williams then compares the new file to a digital guideline based on the original design. The recorded file becomes like a transparency overlaid on drawings of the original design. Any discrepancy between the hull and its original design are immediately apparent.

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