Do you need that extra cost? For a Formula One car, speed is measured in ounces saved, so it clearly makes sense — for a boat to take your family on an afternoon outing, perhaps not so much. However, you can’t disregard the “cool” factor. Those thousand-dollar rims on your SUV don’t make one iota of difference in speed — but they look great, and so does a carbon-fiber hull, as long as the builder uses clear gelcoat like Carbon Marine does. With colored gelcoat (as used by Yellowfin Yachts on its carbon-fiber models), you need to look places, such as under the gunwale, or in the bilge or engine bay, to see the black-fiber pattern.